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Perennial ryegrass (Lolium perenne) plant breeding has delivered several high performing and broadly adapted cultivar‐endophyte (Epichloë) combinations for the New Zealand pasture‐based livestock industries. However, the trends in key traits and the potential economic value being added to farm systems have not previously been addressed systematically. Rates of gain in yield, nutritive value, phenological and morphological traits, and the economic value of those traits, were estimated among and within ryegrass functional groups (heading date, ploidy) traded commercially between 1973 and 2012. Whole pasture dry matter yield improvements of c. 80 and 60 kg DM/ha per year were identified in in late‐season heading diploids and tetraploids respectively. Trends in metabolisable energy were negative within functional groups, but positive when all cultivar‐endophyte combinations were included in the analysis due to the addition of tetraploids and late‐season heading diploids from the mid‐1990s. The estimated trend in overall economic value (all cultivar‐endophyte combinations included) was $7/ha per year based on DM yield only, about half the rate of gain previously estimated using small‐plot merit testing data. The trend increased to $15/ha per year when ME was included due to the emergence of commercial tetraploids from the early 2000s onwards. Estimated economic gains were high within late‐season heading diploids and tetraploids but not mid‐season diploids. These trends suggest that, if high performing cultivar‐endophyte combinations had been adopted in New Zealand dairy systems, then pasture utilization should have increased by ~1 t DM/ha above the current industry average. Reasons for this apparent discrepancy are discussed. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (PRG, Lolium perenne L.) breeding effort in New Zealand (NZ) has increased since c. 1990, resulting in greater functional trait diversity (e.g. heading date, ploidy, and associated Epichloë endophyte strain) in commercial products. This study quantified the variation, associations and interactions in dry matter (DM) yield, nutritive value and persistence‐related traits among commercial cultivar‐endophyte combinations released between 1973 and 2012, as a basis for assessing gains in value being delivered to the pasture‐based livestock industries. Twenty‐four or 28 combinations were compared over 3 years in two trials in each of two regions: Waikato in northern NZ (dryland), and Canterbury in central eastern South Island (irrigated). Cultivar‐endophyte combinations were sown in mixtures with white clover, and pastures were intensively grazed 8–11 times per year by dairy cows. Principal Component Analysis identified 4 distinct clusters for the DM yield variables and for metabolisable energy (ME) content in each of the four trials. A broadly‐adapted group of three late‐season flowering, AR37‐infected diploids with NZ and Spanish breeding backgrounds dominated the highest‐yielding clusters. Tetraploids dominated the high ME content clusters. Interactions with region were observed throughout the data set: the strongest of these was driven by endophyte strain effects in Waikato. High‐yielding cultivar‐endophyte combinations in these trials were also generally high‐yielding in the standard cultivar merit testing system operated in New Zealand, as interpreted via the DairyNZ Forage Value Index. However, alignment was poorer for medium‐ and lower‐yielding cultivar‐endophyte combinations. Several implications for forage evaluation methods and end‐user industries are identified. [ABSTRACT FROM AUTHOR]

Background: There is little information on the effect of interaction between grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass (Lolium multiflorum Lam). The objective of this work was to evaluate the effect of grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass pasture in a crop-livestock integration system. Methods: A randomized complete block experimental design with a 2×2×5 factorial arrangement was used, with three replications. The study factors were two management grass heights, low height (LH=10 cm) and high height (HH = 25 cm), two different nitrogen fertilization times (NP = nitrogen applied to pasture and NG = nitrogen applied to grains crop) and five evaluation periods. Result: The forage mass was higher at higher handling heights and with lower stocking rate (HH = 3995 kg DM ha-1). The forage density tended to be higher in the plots with lower grass height and nitrogen fertilization (LH = 193.5 and NP = 184.7 kg DM ha-1 cm-1). The highest accumulation rate (AR) and forage production (FP) was observed in managed pastures with HHNP (AR = 120.4 kg DM ha-1 day-1; FP = 18471 kg DM ha-1). The management of grass with HHNP provided higher forage mass, higher accumulation rate and higher dry matter production in ryegrass pasture, due to an adequate stocking rate. [ABSTRACT FROM AUTHOR]

Incorporating plantain with perennial ryegrass and white clover (RGWC) can improve the quality and quantity of grazing pastures; however, the sowing rate could affect the persistence of plantain, pasture yield, and nutritive value in different seasons. The objective of this study was to evaluate the effect of increasing sowing rates of plantain when established with RGWC on the dry matter (DM) yield, botanical composition, nutritive value, and bioactive compounds of the pasture over the first two years after sowing; and to determine the relationship between plantain content and nutritive characteristics in different seasons. The pasture treatments were RGWC, RGWC + low plantain rate (PLL), RGWC + medium plantain rate (PLM), and RGWC + high plantain rate (PLH). The results showed that annual DM yield was similar between treatments. The average plantain content (including leaves and reproductive stem) was 32, 44, and 48% in PLL, PLM, and PLH, respectively. The plantain composition increased in the first 15 months, then declined rapidly to about 20–30% at day 705 after sowing. Compared with RGWC, the plantain-RGWC pastures (PLL, PLM, PLH) had a higher content of organic matter digestibility (OMD), ash, starch, non-structural carbohydrates (NSC), P, S, Ca, Mg, Na, Cl, Zn, B, Co, aucubin, acteoside, and catalpol, while they contained a lower composition of DM%, acid detergent fibre (ADF), neutral detergent fibre (NDF), crude fat (CF), Fe, and Mn. These differences were linearly associated with the content of plantain leaves in the pasture and were higher in summer and autumn than in spring. In conclusion, incorporating plantain into the RGWC pasture can improve herbage nutritive quality, thus potentially increasing farm productivity and environmental benefits. However, further work is required to investigate management interventions to sustain plantain content beyond two years from sowing. [ABSTRACT FROM AUTHOR]

Combining several cultivars within species in seed mixtures is often advocated as a means for improving crop or pasture performance. Herbage accumulation (HA) of perennial ryegrass-white clover pastures sown with a single cultivar representing different functional types of perennial ryegrass was compared with the HA of cultivar mixtures over three years in two contrasting environments (Waikato, dryland; Canterbury, irrigated) under dairy cattle grazing. Functional types were: mid-season flowering diploid, late-season diploid, and late-season tetraploid. Mixture treatments (n = 4 at each site) included all binary combinations plus the three-way combination. Mixture HA and the mean HA of the constituent cultivars did not differ for any of the mixture combinations in either environment, apart from winter in Waikato where the mid-diploid plus tetraploid mix out-yielded the mean of the individual cultivars and tended to increase total annual HA. The total annual HA of the mixtures was between 1.0 and 2.3 t DM/ha/year less than the HA of the highest-yielding individual cultivar included in the mixture in six of the eight mixture-environment combinations. While some benefits of mixtures for controlling grazing outcomes were observed, sowing individual high-performing cultivars is a better overall strategy than mixing cultivars to cover a spectrum of traits. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effect of grazing Lolium perenne (Lp) and Bromus valdivianus (Bv) on the average daily weight gain (ADG) and nitrogen use efficiency (NUE) of Holstein Friesian heifers. Thirty heifers strip-grazed two pasture treatments (Lp and Bv) under a randomized complete block design (n = 3). Nutrient concentration and pasture intake were determined. Urine samples were taken, and the total volume of urine and microbial growth were estimated. Retained nitrogen (N), N intake, N excreted in feces and urine and the nitrogen use efficiency (NUE) were calculated. Lolium perenne showed greater WSC and ME but lower NDF than Bv, whereas crude and soluble protein were unaffected. There were no effects of species on ADG or feed conversion, and DMI was not affected by grass species, or the synthesis of microbial protein and purine derivatives. Ammonia in the rumen, urinary N and total N excreted were greater for heifers grazing Bv. In conclusion, the consumption of forage species did not alter the ADG or NUE of grazing heifers, but N partitioning was modified for heifers grazing Bv, due to the lower WSC/CP ratio compared with Lp. [ABSTRACT FROM AUTHOR]

Australia has tropical, summer dominant rainfall in the north transitioning to temperate, winter dominant rainfall in the south. Temperate pasture species with a cool season growth pattern are commonly grown in the south, but tropical pasture species that are highly productive and responsive to summer rainfall, may also have a role in southern pasture systems with climate change. Determine the value of replacing temperate pastures with tropical pastures; and assess the emergence success of tropical grasses in response to historic climate change in eastern Australia. The AusFarm model was used to test replacing lucerne (Medicago sativa L.) (L); annual ryegrass (Lolium rigidum L.)/subterranean clover (Trifolium subterraneum L.) (RC); or lucerne/annual ryegrass/subterranean clover (LRC) with tropical pasture at varying rates of inclusion at five locations across the subtropical-temperate transition zone. The emergence success of tropical grasses with a bare fallow, short fallow and increased ground cover management was also tested. The modelling covered two periods, the Far Climate (1960–1990) and the Near Climate (1990–2020). Tropical pastures had higher plant growth in late summer-early autumn when temperate pastures are less active. Pasture growth decreased from the Far to the Near Climate period across all sites. The pastures with L lost the most production over this period, with minimal change in other pasture types. Supplementary feeding was reduced at all sites with the inclusion of tropical pastures. The cost of supplementary feeding from the Far to the Near Climate increased by $20/ha with increased variability between years, which in-turn decreased gross margin by an average of $26/ha. Tropical pastures improved profitability on average by $24/ha (11%), but with different responses between environments. At the low rainfall sites (Condobolin and Leeton) there was a substantial benefit when tropical grass-clover (TC) pasture replaced L, but at the higher rainfall sites (Cowra and Wagga Wagga) the benefit was replacing RC with TC. There was a gradient of successful emergence from very high (>90%) in the north, to reduced opportunities in the south (<45%), and marginal influence of sowing management. Adding tropical pastures to grazing systems with temperate pastures increased summer-autumn growth, the animal requirements met by pasture, and gross margins. Profitability of livestock systems decreased with climate change, but this can be overcome by optimising pasture composition. Fewer years are favourable for establishment of tropical pastures in more temperate environments, therefore establishment strategies need to be adjusted and field tested. • Tropical pastures have potential in temperate grazing systems due to climate change. • Tropical pastures increased plant growth over summer when temperate pastures are less active. • Tropical pastures decreased supplementary feeding and increased gross margin. • Poor establishment conditions limit the use of tropical grasses in temperate environments. • Profit of livestock systems decreased with climate change but less so with tropical pastures. [ABSTRACT FROM AUTHOR]

In the dairy region of northern Victoria, Australia, the performance of temperate perennial dairy pastures is often poor over summer due to a combination of high temperatures and limited water availability that can restrict dry matter production and plant survival. This review summarizes published and unpublished research on perennial ryegrass, mostly undertaken in the northern Victoria region over the past decade, to help determine its future role in this environment. It includes information from a series of field experiments or case studies where the effects of heat and restricted irrigation on the growth and nutritive characteristics of perennial ryegrass were examined. This research involved investigations on whether plant survival under the stressed experimental conditions could be influenced by plant genotype, irrigation, and grazing management strategies, as well as by the presence of endophyte. In conclusion, it was difficult to identify any irrigation, grazing management or plant genotype effect that consistently improved the performance of perennial ryegrass in the hot, dry summers of northern Victoria, Australia. The incidences of extreme heat events and low water availability in this region are increasing, and the role of C3 perennial grasses as major suppliers of feed for dairy cows is diminishing. A major focus for the dairy industry in this region is now to identify new farming systems and alternative species that may be better adapted to the climate environment than perennial ryegrass, as well as be capable of adapting to year‐to‐year variations in irrigation water supply. [ABSTRACT FROM AUTHOR]

Our aim was to evaluate whether increasing soluble carbohydrates in the herbage by changing the time of the grazing session or including Acacia mearnsii tannin in the diet would affect intake, digestion, N partitioning, and productive performance of dairy cows fed a diet combining ryegrass herbage with partial total mixed ration (PMR). We hypothesized that both strategies could reduce the concentration of NH 3 -N in the rumen, reducing urinary N excretion. Nine Holstein cows were used in a triplicate 3 × 3 Latin square experiment with 3 experimental periods of 22 d. The cows were fed a fixed amount of PMR [60% of the predicted individual dry matter intake (DMI)], and an unrestricted amount of herbage in 1 grazing session of 5 h/d. The treatments were (1) morning grazing session and afternoon PMR meal (AM); (2) morning PMR meal and afternoon grazing session (PM); and (3) morning grazing session and afternoon PMR meal supplemented with 15.0 g of tannins/kg of PMR dry matter (TAN). Milk production was not affected by treatments. Although the protein concentration was lower for TAN than for PM, no differences were detected for the yield of any component between treatments. The concentration of individual or grouped fatty acids in milk fat was not affected by treatments, except for 16:1 cis -9 and Δ9-desaturase ratios 14:1/14:0 and 16:1/16:0, which were lower for TAN. Treatments did not affect total DMI, but PM tended to increase herbage DMI and reduce dry matter and crude protein digestibilities. Treatments did not affect cow eating and ruminating behavior except for the proportion of time spent eating PMR, which was higher for PM and TAN. Although no relevant effects of treatments on ruminal fermentation, purine derivatives excretion in urine, or N excretion in milk were detected, both PM and TAN decreased the total N excreted in urine by an average of 8% compared with AM. In conclusion, changing the grazing session from the morning to the afternoon and including tannins in the diet were effective in decreasing the excretion of urinary N but did not change the productive performance of dairy cows fed PMR and ryegrass herbage. [ABSTRACT FROM AUTHOR]

Simple Summary: Supplementing non-structural carbohydrates can enhance feed intake, performance, and nitrogen use in dairy cows grazing protein-rich swards. The present study thus analyzed the effects of feeding lactating cows two types of cereal grains, when their majority was either offered before or after grazing an alfalfa-ryegrass sward. Results showed that supplementing corn meal as a slowly degradable starch source after grazing and oat meal as a rapidly degradable starch source before grazing may improve milk yield and nitrogen use in grazing dairy cows. Hence, matching the choice of concentrate feed and the timing of its supplementation may aid to reduce nitrogen emissions from pasture-based dairy cattle systems while making use of the local, human-inedible forage resources from grasslands. The aim was to analyze the effects of two cereal grains differing in nutritional composition and starch degradation characteristics and the timing of their supplementation on feed intake, rumen microbial protein synthesis (MPS), performance, and nitrogen use of lactating dairy cows grazing an alfalfa-ryegrass sward. Four dietary treatments were tested in 24 lactating Brown Swiss cows in an incomplete 4 × 3 Latin square design. Cows were supplemented with 3.5 kg/d (as-fed basis) of a corn-based or an oat-based concentrate mixture (CM), of which either the majority (2.5 vs. 1.0 kg/d) was offered before or after grazing. Feed intake was similar across diets, but the interaction between type of CM and timing of supplementation affected eating time (p = 0.010), milk protein (p = 0.013) and energy-corrected milk yields (p = 0.025), efficiency of rumen MPS (p = 0.094), and nitrogen use efficiency (p = 0.081). Most of these variables were greater when the majority of the corn-based CM was offered after grazing and the oat-based CM before grazing. Supplementing slowly degradable starch sources after and rapidly degradable starch sources before grazing may improve the efficiency of rumen MPS, milk performance, and nitrogen use efficiency in dairy cows grazing alfalfa-ryegrass swards. [ABSTRACT FROM AUTHOR]

The objective was to determine the effect of grazing fodder beet versus ryegrass-dominant pasture from mid-to-late gestation on dam and offspring performance under practical farming conditions. Twin-bearing ewes were randomly allocated to grazing regimes of either fodder beet plus ad libitum ryegrass/clover hay (FB; n = 100) or ryegrass-dominant pasture plus ad libitum ryegrass/clover hay (RG; n = 100) with three replicates per group, from pregnancy day (P) 100–110 to birth. At P135, 10 ewes per treatment were randomly selected from each replicate, slaughtered and back fat and eye muscle depth and fetal body weight and composition were measured. Samples were evaluated for selected blood metabolites. Ewe BW and BCS change and lamb growth were measured, and lamb survival from birth to weaning calculated. Compared with RG, FB ewes had lower ADG and overall lower BCS resulting from increased mobilisation of both fat and muscle. Lambs born to FB-ewes had lower BW and postnatal growth rates and increased mortality from birth to weaning (29% versus 12%). Body composition and blood parameters indicated that FB compared to RG ewes were subject to undernutrition. This study provides new insights into the consequences of FB grazing regimes, as an alternative to ryegrass pasture, on animal performance. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is a widely sown pasture species in temperate regions. Under heat and moisture-deficit stress, its production is suppressed and tiller mortality increases, particularly when plants are simultaneously exposed to other stresses such as intense defoliation. We investigated the effects of extended grazing exclusion periods in spring and summer on herbage and soils of rotationally grazed, perennial ryegrass-dominant pastures at a summer-wet site and a summer-dry site in sheep and beef hill country in New Zealand. Treatments comprised 'grazed' (conventional rotational grazing), 'early opening' (grazing exclusion from mid-spring to mid-summer to allow perennial ryegrass to flower), and 'deferred grazing' (grazing exclusion from mid-spring to late summer to allow perennial ryegrass to flower and set seed). At both sites, deferred grazing increased perennial ryegrass tiller density and total vegetation cover, and reduced the abundance of broadleaf species and Pseudopithomyces chartarum spores for up to 15 months after exclusion compared with the grazed control. Herbage production was reduced during the deferred period but there was a growth surge thereafter so that herbage production over the study period was similar in the deferred and grazed treatments. Pasture nutritive values were lower in the deferred than the grazed treatment during the exclusion period but were similar in all treatments by the end of the following winter. In the autumn after deferring, seedlings contributed ~50% of the perennial ryegrass tillers present at the summer-dry site but only ~10% at the summer-wet site, where regrowth tillering of existing plants contributed a high proportion of the perennial ryegrass tillers present. Overall, early opening had few effects on the pasture, whereas deferred grazing had numerous positive effects on the pasture but only short-term effects on soil quality. We investigated the impacts of deferred grazing (livestock excluded from mid-spring to late summer to enable perennial ryegrass to flower and set seed), early opening (livestock excluded from mid-spring to early summer to enable perennial ryegrass to flower) and standard rotational grazing on hill country pastures and soils under beef and sheep grazing. Compared with standard rotational grazing, deferred grazing had positive effects on pasture productivity but only short-term effects on soil quality, whereas early opening had few effects on the pastures or soils. [ABSTRACT FROM AUTHOR]

Grazing efficiency has been shown to differ between perennial ryegrass varieties. Such differences affect the utilization of grass within grazing systems, influencing the profitability of grass-based ruminant production systems. The Pasture Profit Index (PPI) is an economic merit grass variety selection tool developed to identify varieties with the greatest economic potential for grass-based dairy production systems. A new grass utilization subindex was developed and incorporated into the PPI to identify varieties with superior grazing efficiency. The subindex rewards varieties with superior grazing efficiency, measured as Residual grazed height, as these varieties allow increased amounts of herbage dry matter to be used by grazing animals. The economic values of all other traits within the PPI were reviewed and updated to ensure that the index was reflective of the current economic scenarios with appropriate assumptions included in the models, thus ensuring that varieties excelling in the agronomic traits with the greatest effect on profitability were recognized. The difference between the highest and lowest performing varieties for the grass utilization trait ranged from €23 to −€24. A range of €211 to €43 was recorded between the highest and lowest ranked varieties within the updated PPI. Spearman's rank correlation between the updated and original PPI lists was 0.96. The introduction of the utilization subindex will allow farmers to make informed variety selection decisions when reseeding pasture, particularly on their grazing platforms and it will allow a demand-based communication process between the farmer and the grass merchant or breeder, ultimately affecting trait selection for future breeding strategies. [ABSTRACT FROM AUTHOR]

Low dietary energy and decreased intake of herbage have been attributed to the reduced performance of grazing dairy cattle. We hypothesized that grasses with inherently greater energy would interact in a complementary way with condensed tannins (CT) in birdsfoot trefoil to increase herbage intake by grazing dairy heifers. Eight pasture treatments comprising high-sugar perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), and tall fescue [ Schendonorus arundinaceus (Schreb.) Dumort] were established in Lewiston, Utah as monocultures and binary mixtures with birdsfoot trefoil (Lotus corniculatus L.; BFT). Pasture treatments were rotationally stocked by Jersey heifers for 105 d in 2017 and 2018, and herbage samples were collected pre- and postgrazing for each 7-d grazing period and analyzed for herbage mass, nutritive value, and apparent herbage intake. We observed differences among pasture treatments in herbage quantity and nutritive value, as well as differences in herbage intake by grazing Jersey heifers. On average, grass-BFT mixtures had greater herbage intake than grass monocultures, and every grass-BFT treatment individually had greater herbage intake than their respective grass monocultures. Using multivariate analyses, we determined that approximately 50% of the variation in herbage intake was due to nutritive and physical herbage characteristics, with the most explanatory being characteristics related to fiber and energy, followed by those related to the percent of BFT in the herbage. Grass monocultures exhibited a range of inherent dietary energy, but there was indication that an imbalance of energy to crude protein (e.g., protein deficient) reduced intake of grass monocultures. Moreover, there was some evidence of a complementary effect between increased dietary energy and CT; however, low CT levels made it impossible to determine the effect of CT on herbage intake per se. This study confirmed that chemical and physical characteristics inherent to different pasture species have a large effect on herbage intake by grazing cattle. Pastures planted to binary mixtures of nutritious grasses and birdsfoot trefoil increase herbage intake of temperate pastures by grazing Jersey heifers. [ABSTRACT FROM AUTHOR]

Several studies have been conducted to improve grazing management and supplementation in pasture-based systems. However, it is necessary to develop tools that integrate the available information linking the representation of biological processes with animal performance for use in decision making. The objective of this study was to evaluate the precision and accuracy of the Molly cow model predictions of ruminal fermentation, nutrient digestion, and animal performance by cows consuming pasture-based diets to identify model strengths and weaknesses, and to derive new digestive parameters when relevant. Model modifications for adipose tissue, protein synthesis in lean body mass and viscera representation were included. Data used for model evaluations were collected from 25 publications containing 115 treatment means sourced from studies conducted with lactating dairy cattle. The inclusion criteria were that diets contained ≥45% perennial ryegrass (Lolium perenne L.), and that dry matter intake, dietary ingredient composition, and nutrient digestion observations were reported. Animal performance and N excretion variables were also included if they were reported. Model performance was assessed before and after model reparameterization of selected digestive parameters, global sensitivity analysis was conducted after reparameterization, and a 5-fold cross evaluation was performed. Although rumen fermentation predictions were not significantly improved, rumen volatile fatty acids absorption rates were recalculated, which improved the concordance correlation coefficient (CCC) for rumen propionate and ammonia concentration predictions but decreased CCC for acetate predictions. Similar degradation rates of crude protein were observed for grass and total mixed ration diets, but rumen-undegradable protein predictions seemed to be affected by the solubility of the protein source as was the intestinal digestibility coefficient. Ruminal fiber degradation was greater after reparameterization, driven primarily by hemicellulose degradation. Predictions of ruminal and fecal outflow of neutral detergent fiber and acid detergent fiber, as well as total fecal output predictions, improved significantly after reparameterization. Blood urea N and urinary N excretion predictions resulted in similar accuracy using both sets of model parameters, whereas fecal N excretion predictions were significantly improved after reparameterization. Body weight and body condition score predictions were greatly improved after model modifications and reparameterization. Before reparameterization, yield predictions for daily milk, milk fat, milk protein, and milk lactose were greatly overestimated (mean bias of 61.0, 58.7, 73.7, and 64.6% of mean squared error, respectively). Although this problem was partially addressed by model modifications and reparameterization (mean bias of 3.2, 1.1, 1.7, and 0.4% of mean squared error, respectively), CCC values were still small. The ability of the model to predict grass digestion and animal performance in dairy cows consuming pasture-based diets was improved, demonstrating the applicability of this model to these productive systems. However, the failure to predict grass digestion based on standard model inputs without reparameterization indicates there are still fundamental challenges in characterizing feeds for this model. [ABSTRACT FROM AUTHOR]

Context: Economic modelling identified that mating of ewe lambs for lambing at 1 year of age has the potential to increase the profitability of sheep-production systems in south-western Victoria. In order to optimise reproductive rates, ewe lambs should weigh at least 35–40 kg, have a condition score (CS) of 3.0 at mating, and be gaining weight (100–150 g/day) during mating. However, typical perennial ryegrass (Lolium perenne L.) pastures in south-west Victoria do not support the attainment of these targets without additional supplementation. Aim: Our research aimed to determine how grazing summer-active pastures or brassica (Brassica napus L.) forages affects the liveweight, CS, conception and reproductive rate of ewe lambs when offered before and during mating compared with a system using perennial ryegrass plus supplement. Methods: A field experiment was conducted at Hamilton, Victoria, Australia, in 2014 and 2016 testing seven forage treatments replicated four times in a complete block design. The treatments were: canola (B. napus , two treatments of different cultivars), forage brassica, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.) and perennial ryegrass. Key results: Ewe lambs grazing canola or forage brassica had higher (P < 0.05) liveweight gains during the pre-mating and mating periods than those grazing the perennial ryegrass treatment (148 vs 75 g/day in 2014, s.e.m. 17; 139 vs 54 g/day in 2016, s.e.m. 17). In 2014, spring-sown dual-purpose canola, lucerne and chicory resulted in higher (P < 0.05) reproductive rates (144–151%) than the perennial ryegrass treatment (103%); forage brassica and plantain gave intermediate results (128% and 129%). Conclusion: Brassica forages (including spring-sown canola), lucerne and chicory can support the attainment of key liveweight and CS targets for successful mating of ewe lambs in autumn. Implications: Spring-sown canola is therefore a viable alternative forage for use by livestock producers in southern Australia and presents an opportunity to incorporate an alternative income stream in mixed-farming systems. Mating of ewe lambs for lambing at 1 year of age has the potential to increase the profitability of sheep-production systems; however, successful mating of ewe lambs requires that they have reached a bodyweight of 35–40 kg, have a condition score of at least 3.0, and be gaining weight before and during mating. Grazing dual-purpose canola crops during summer and autumn enables ewe lambs to meet these targets and improves liveweight gains and reproductive performance relative to traditional perennial ryegrass pastures. The implications are a more productive ewe flock, and a flock that produces more lambs over the duration of a ewe's lifetime. [ABSTRACT FROM AUTHOR]

Context: Filling the summer–autumn feed gap is a key priority for sheep producers in southern Australia's high-rainfall zone. Aim: Our research aimed to determine whether spring-sown winter-type canola (Brassica napus L.) could increase herbage mass and nutritive characteristics during summer and autumn relative to other forage options in southern Australia's HRZ. Methods: A field experiment was conducted at Hamilton, Victoria, Australia, in 2014 and 2016 testing seven forage treatments replicated four times in the complete block design. The treatments were: canola (two treatments of different cultivars), forage brassica (B. napus), lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.) and perennial ryegrass (Lolium perenne L.). Key results: Herbage mass and nutritive characteristics of the canola varieties did not differ (P > 0.05) from forage brassica. Herbage mass in March 2014 was 3.35–3.64 t dry matter (DM)/ha for brassicas; 1.05–1.37 t DM/ha for perennial ryegrass, plantain and chicory; and 2.94 t DM/ha for lucerne (P < 0.001, l.s.d. = 1.20). In March 2016, herbage mass was 1.86–2.05 t DM/ha for brassicas and 2.14–2.49 for the other forage treatments (P < 0.05; l.s.d. = 0.47). Brassicas had higher (P < 0.05) metabolisable energy (ME) concentrations and lower (P < 0.05) neutral detergent fibre (NDF) concentrations on most sampling dates than chicory, plantain, lucerne and perennial ryegrass. The crude protein (CP) concentration of the brassica treatments was not different (P > 0.05) from that of the other forage treatments. Concentrations of ME, CP and NDF were very similar between years for the brassicas, with March ME, CP and NDF concentrations of 12.0–13.2 MJ/kg DM, 14.0–20.1% DM and 16.7–23.6% DM. Conclusion: Canola provided increased or equivalent levels of herbage mass and nutritive characteristics compared with other forage options in south-western Victoria on most, but not all, sampling dates. However, the annual spring-sowing requirement is a challenge under variable spring-rainfall conditions and may limit productivity if there is poor establishment. Implications: Spring-sown canola is a viable alternative forage for livestock producers and offers a potential second income stream in high-rainfall-zone livestock farming systems. Filling the summer–autumn feed gap is a key priority for sheep producers in southern Australia's high-rainfall zone, with summer and autumn traditionally being a time of feed shortage for livestock production. Winter-type canola can produce up to 3.5 t/ha of high-quality feed for grazing livestock during this key summer–autumn period. This provides livestock producers with the opportunity to increase production during this time of year, which could involve finishing livestock to higher slaughter weights or increasing the reproductive performance of ewes, utilising forage rather than purchasing supplementary feeds. [ABSTRACT FROM AUTHOR]

We evaluated Italian ryegrass (Lolium multiflorum Lam.) establishment in a factorial of grazing intensity (intense, moderate, moderate‐light, light, and no grazing, with target average sward heights of 10, 20, 30, and 40 cm in the grazed plots) and additional seeding (self‐seeding with or without additional seeding) in an integrated soybean‐beef cattle system in southern Brazil. Grazing treatments were imposed in winter (June–July) and followed by a direct‐seeded soybean crop (November). The establishment was quantified prior to the stocking periods in 2017 and 2018, corresponding to self‐seeding from 2016 and 2017. Intense grazing impaired ryegrass re‐establishment, resulting in larger individual plants (0.54 vs. 0.15 g dry matter plant−1) but lower population density (57 vs. 1,355 plants m−2) than in the other treatments. Additional broadcast ryegrass seeding did not fully compensate for the reduced natural reseeding in this treatment. The addition of seeds under intense grazing increased plant population density to values comparable to moderate grazing intensities but reduced individual plant mass, limiting herbage mass attained by the end of the pasture establishment phase. Contrastingly, the various combinations of individual plant mass and population density were sufficient to maintain herbage masses in moderate to light grazing intensities that were comparable to that in the ungrazed treatment, regardless of seed addition (63 vs. 180 g DM m−2 for intense grazing vs. the average of other treatments over the whole establishment phase). Moderate grazing, e.g., target sward heights of 20 cm or greater, is necessary to achieve a system that can sustain itself without seed addition. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of perennial ryegrass (Lolium perenne L.; PRG) ploidy and white clover (Trifolium repens L.) inclusion on milk production, dry matter intake (DMI), and milk production efficiencies. Four separate grazing treatments were evaluated: tetraploid PRG only, diploid PRG only, tetraploid PRG with white clover, and diploid PRG with white clover. Individual DMI was estimated 8 times during the study (3 times in 2015, 2 times in 2016, and 3 times in 2017) using the n -alkane technique. Cows were, on average, 64, 110, and 189 d in milk during the DMI measurement period, corresponding to spring, summer, and autumn, respectively. Measures of milk production efficiency were total DMI/100 kg of body weight (BW), milk solids (kg of fat + protein; MSo)/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/kg of total DMI. Perennial ryegrass ploidy had no effect on DMI; however, a significant increase in DMI (+0.5 kg/cow per day) was observed from cows grazing PRG-white clover swards compared with PRG-only swards. Sward white clover content influenced DMI as there was no increase in DMI in spring (9% sward white cover content), whereas DMI was greater in summer and autumn for cows grazing PRG-white clover swards (+0.8 kg/cow per day) compared with PRG-only swards (14 and 23% sward white clover content, respectively). The greater DMI of cows grazing PRG-white clover swards led to increased milk (+1.3 kg/cow per day) and MSo (+0.10 kg/cow per day) yields. Cows grazing PRG-white clover swards were also more efficient for total DMI/100 kg of BW, solids-corrected milk/100 kg of BW, and MSo/100 kg of BW compared with cows grazing PRG-only swards due to their similar BW but higher milk and MSo yields. The results highlight the potential of PRG-white clover swards to increase DMI at grazing and to improve milk production efficiency in pasture-based systems. [ABSTRACT FROM AUTHOR]

Grazing birds like geese can have a big impact on agricultural land, potentially causing damage to crops. Their exploitation of agricultural land varies within and between seasons, and these temporal grazing patterns can be influenced by management. Furthermore, management practices using scaring and accommodation aim to influence local grazing pressures. To achieve efficient goose management we need a good understanding of the effects of timing and intensity of grazing on grass development and subsequent yield loss. We performed an exclosure study on twelve fields in Friesland (Fryslân), the Netherlands to study the effect of grazing on grass development and potential yield loss. Grazing was prevented either from November or from early April until farmers anticipated their first harvest. Every two weeks we measured grass height and calculated growth in exclosures and in ungrazed plots, and performed dropping counts. The results show that the difference in grass height between grazed and ungrazed plots increases with grazing pressure, but less so for higher grazing pressures. We also find that both winter and spring grazing can result in a larger difference in grass height between grazed and ungrazed plots, and grazing into the growing season delays the start of grass growth. This appears due to the relationship between grass height and growth rate. Because the optimal height for growth increases over the season, spring grazing has a much larger impact on grassland yields than winter grazing. Overall these results show that the amount of yield loss depends on different aspects of grazing, most prominently the recovery time, duration and grazing intensity. We hypothesize that barnacle geese may select fields with denser swards and may stimulate sward density by frequent grazing throughout winter and early spring as well as across consecutive years. Future studies should look into the effect of harvest delays and sward density on the size and quality of yield across the season and especially at the last cut. Management with scaring and accommodation may be able to reduce overall yield losses, but the effect may depend on the timing and location of scaring. • Both winter and spring grazing on ryegrass can reduce grass height at first harvest. • Spring grazing results in a larger difference in height between grazed and ungrazed grass. • Spring grazing can delay the start of grass growth. • There is an optimal grass height for growth that changes with season. • The difference in grass height increases with grazing pressure, but non-linearly. [ABSTRACT FROM AUTHOR]

Sheep farmers can increase production levels as a means to improve economic outcomes. However, this intensification can potentially result in more nitrogen (N) leaching which is at odds with the increasing pressure on farmers to reduce the quantity of N lost into the environment. Therefore, there is increasing interest in the use of alternative forages, such as Italian ryegrass and plantain, which could potentially allow farmers to increase production while decreasing N leaching. This study quantified and compared the quantity of N leaching under sheep grazing four different forages: perennial ryegrass/white clover (RGWC), Italian ryegrass/WC (IRWC), plantain/WC (PWC) and a winter brassica. Five replicates of each forage were established on plots of 800 m2 (40 m x 20 m). Each plot had an independent mole-pipe drain system with tipping-bucket monitoring equipment at the end of the pipe drain. Drainage volume and N concentrations (nitrate-N: NO 3 ⁻-N; ammonium-N; total-N) in drainage water were measured to estimate N losses. The forages were grazed according to the best management practice for each forage type over a two-and-a-half-year period (Year 1: July-December 2019; Year 2: January-December 2020; and Year 3: January-December 2021). In the first two years of this study, NO 3 ⁻-N leaching losses under IRWC and PWC were very small (ranging from 0.4 to 0.5 kg N/ha), and they were not different (P > 0.05) from those under RGWC. However, in Year 3, the leaching losses under IRWC and PWC treatments were greater (P < 0.05) than those under RGWC. This increased leaching was probably due to the need to re-establish these pastures. As part of renewing these swards, the IRWC and PWC plots were fallow during the key late summer-autumn period. In contrast, NO 3 ⁻-N leaching losses under brassica forages (3.5–6.4 kg N/ha) were greater (P < 0.05) than under RGWC (0.5–1.5 kg N/ha). Overall, the leaching losses measured under sheep grazing the forages were much smaller than those commonly reported by dairy studies. [Display omitted] • In recent years, there has been significant concern regarding the leaching of nutrients from grazing systems. • This study quantified the amount of nitrogen leaching lost in drainage water from sheep grazing four different forages. • Mole-and-pipe drainage systems were used to monitor drainage volume and collect samples. • Overall, leaching losses under sheep grazing forages were small. • Modern sheep grazing systems may offer mitigation options for dairying areas with high NO 3 - leaching. [ABSTRACT FROM AUTHOR]

The aim of the paper is to highlight the role of natural germoplasm resource of the species Lolium perenne by adapting it to a wide variety of abiotic conditions. The impact of the presence of the species together with other legume species such as Trifolium repens in the construction of multifunctional temperate climate associations is also studied. The concept of meadow multifunctionality has developed with the reconsideration of their sustainability character in terms of an emphasis on the negative impact on the environment. Land use change in recent decades, the abandonment of grazing and the decline of traditional agricultural practices or afforestation are a major threat to biodiversity. Often the bispecific dominance between Lolium perenne and Trifolium repens is improve both feed quality and soil quality due to the added value of fixing atmospheric nitrogen. The species of Lolium perenne due to its high ecological plasticity is thus considered to be particularly important especially due to the fact that it covers a wide range of environmental conditions thus developing models of great genetic diversity which leads to a development of genomic resources. Lolium perenne is thus adapted to defoliation, fertilization and growth cycles, which is particularly important because defoliation through animal grazing can have major effects on the structure and functioning of grassland ecosystems affecting the production of shoots and root rotation of communities. of plants, but also photosynthetic rates and carbon allocation in plants: energy flow in the plant-soil system. Thus, the highlighting of the qualities of Lolium perenne species are important premises for the genetic progress of this species but especially for understanding the natural functioning of plant associations dominated by it, which leads to environmentally friendly management practices. [ABSTRACT FROM AUTHOR]

Recent years have seen a decline in herbage production and tiller populations in New Zealand's perennial ryegrass (Lolium perenne) dairy pastures. One hypothesis is that modern genotypes are less suited to the warmer, drier weather experienced under changing climate patterns. In this study, a combination of long‐term trial data (2011–2017) and a process‐based pasture model (BASGRA) was used to explore the causes and possible mitigation of the observed production and population loss at three sites (dryland sites in Northland and Waikato and an irrigated site in Canterbury). Bayesian calibration was used to identify the model parameter sets that were consistent with the trial data and to identify differences in plant morphology and responses between sites. The model successfully simulated the observed differences in tiller numbers between the dryland sites, where populations and production declined rapidly after the second year and the irrigated site where populations and production were maintained. Analysis of the model calibrations along with preliminary scenario simulations suggests that increased tiller mortality associated with drought was the main cause of persistence failure at the dryland sites and that decreasing grazing pressure or breeding for tolerance to higher temperatures may not be successful in preventing this. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify amino acid (AA) profiles in plasma collected from dairy heifers grazing swards containing ryegrass/clover, chicory and plantain in autumn and spring. The study comprised a 28-day autumn trial and a 21-day spring trial using 56 Friesian x Jersey heifers. Total AA concentrations ranged from 2849 to 3165 μM in autumn and from 3195 to 3454 μM in spring, with no treatment effect. Season affected essential AA (EAA) and total AA concentrations. Total plasma AA concentrations were lower in autumn (2965 μM) than in spring (3303 μM). Based on these results, feeding dairy heifer's either pure chicory, binary mixture or pure plantain does not affect EAA and total AA of Friesian x Jersey heifers. Further, no relationship was established between AA and weight gain of heifers in this study. [ABSTRACT FROM AUTHOR]

The excretion of urinary nitrogen (N), one of the most important environmental contaminants from livestock systems, is highly correlated with milk urea N content. The objective of this research was to evaluate the use of different types of corn supplementation on milk urea N in grazing dairy cows. Twelve Holstein × Jersey lactating dairy cows were divided into six uniform groups according to milk production, lactation stage and live weight. Treatments were compared according to a 3 × 3 replicated Latin square experimental design, with three periods of seventeen days (twelve days to adaptation and five to measurements). The experimental treatments were exclusively grazing (G); grazing + supplementation with 4.2 kg DM of corn silage (CS) and grazing + supplementation with 3.2 kg DM of ground corn (GC). The pasture used was annual ryegrass (Lolium multiflorum L.) and white oats (Avena sativa L.). The milk protein production increased 65 g/day in the GC treatment group compared to the G and CS groups. The supplemented dairy cows showed lower milk urea N (-2.8 mg/dL) than unsupplemented cows, but the N utilization efficiency (g N output in milk/g N intake) did not change between treatments (average = 0.26). Additionally, there was a relationship between milk and plasma urea nitrogen concentrations (R² = 0.64). In conclusion, for dairy cows grazing annual temperate pastures, corn ground supplementation increased milk protein production and reduced the excretion of milk urea N, whereas corn silage reduced the excretion of milk urea N without affecting milk protein production. [ABSTRACT FROM AUTHOR]

Defoliation often has little effect on the percent plant root length colonised by arbuscular mycorrhizal (AM) fungi, and this has been interpreted as a lack of support for the carbon limitation hypothesis. We performed an experiment with three levels of repeated defoliation (none, every 3 weeks and weekly) of Lolium rigidum growing in pasture soil, and assessed colonisation of roots by naturally occurring AM fungi over 4 months in the glasshouse. Surprisingly, the percent root length colonised by AM fungi increased with defoliation. We also assessed root mass and the length of colonised root to obtain an estimate of the quantity of mycorrhizal root. As expected, both root mass and length of mycorrhizal root decreased with defoliation, as did soluble sugars in the roots. Thus, increasing the frequency of defoliation reduced mycorrhizas consistent with the carbon-limitation hypothesis. Such a decline in mass of mycorrhizal root could contribute to reducing soil biological fertility in pastures over time. [ABSTRACT FROM AUTHOR]

Small-scale dairy systems contribute to ameliorate rural poverty and to local milk supply. Their sustainability is limited by high feeding costs, mainly from purchased concentrates (CC); whereas a higher reliance on quality forage may improve profitability; but high stocking rates may justify high CC use. The objective of this work was to assess the productive and economic response by grazing dairy cows to levels of CC under grazing of ryegrass--white clover pastures under high stocking rate (4 cows/ha). Six Holstein milking cows were replicated assigned 3 X 3 Latin Square arrangements. Daily milk yield and composition were recorded, and feed intake estimated from utilised metabolizable energy. Treatments were: T1= 1.0 kg T6= 3.0 kg and T6= 6.0 kg concentrate/cow/d. There were significant differences (P<0.05) for milk yield, with T6 having higher yields than T1 and T3. There were no significant differences in milk protein or fat content among treatments (P>0.05). Herbage intake was significantly (P<0.05) lower in T6, with no differences (P>0.05) between T1 and T3. There were no differences in margins over feeding costs, but feeding cost per kg of milk was 2.2 times higher in T6 compared to T1, and margin per kilo of milk was 26 % higher in T1 than T6. Although milk yields are higher with T6, T1 and T3 require less expenditures and margins are similar. Supplementation may alleviate high grazing pressure that deteriorates pastures, ensuring the long-term sustainability of small-scale dairy farming systems. [ABSTRACT FROM AUTHOR]

In perennial ryegrass breeding programmes, dry‐matter yield (DMY) of individual plots is monitored destructively at the different cuts or derived from non‐destructive canopy height measurements using devices like rising plate meters (RPM). These approaches both have constraints. Destructive sampling implies low temporal resolution, restraining the study of dry‐matter accumulation rates, while RPM measurements are influenced by the canopy structure and limit intra‐field variability identification. We present a phenotyping methodology, based on the use of an affordable RGB camera mounted on an unmanned aerial vehicle (UAV), to monitor the spatial and temporal evolution of canopy height and to estimate DMY. Weekly flights were carried out from April to October above a field comprising a diverse set of accessions. To test the capacity of UAV imagery to estimate canopy height, 8 ground control points and 28 artificial height references were placed at different locations. Accurate flights with an RMSE as low as 0.94 cm were achieved. In addition, canopy height was recorded using an RPM and destructive biomass samples were collected. Different models (linear, multiple linear, principal components, partial least squares regression and random forest) were used to predict DMY, and their performance was evaluated. The best estimations were obtained by combining variables including canopy height, vegetation indices and environmental data in a multiple linear regression (R2 = .81). All models built using UAV data obtained a lower RMSE than the one using RPM data. The approach presented is a possibility for breeders to incorporate new information in their selection process. [ABSTRACT FROM AUTHOR]

• An overview of the effects of forage type and season on retention time and the fatty acids profile of the rumen fluid of steers grazing a temperate grass, a range of tropical and subtropical grasses and a legume/grass mix. • The native speargrass Heteropogon contortus in dry season had the lowest crude protein and digestibility, which was associated with a low concentration of volatile fatty acids, and longer retention time (20 h). • The retention time of all wet season grasses, including the C3 ryegrass Lolium perenne , was similar, despite some small quantitative significant differences, and similar to legume/grass mix in the dry season. • Total unsaturated fatty acids in rumen fluid was reduced markedly compared to the concentration of the forages with some small differences between forage species. • It was concluded that retention time of wet season grasses was similar across all forage species (8-11 hrs) and would not result in different times for biohydrogenation within the rumen. The effects of forage type and season on retention time (RT) and the fatty acid (FA) profile of the rumen fluid (RF) of steers grazing a range of grasses and a legume/grass mix were evaluated. Four rumen cannulated steers (790 ± 17 kg body weight (BW) grazed individual wet season pastures (herbage mass 2600-6200 kg DM/ha of C3 ryegrass Lolium perenne and C4 grasses pangola Digitaria eriantha , signal grass Brachiaria decumbens , star grass Cynodon dactylon , kikuyu Pennisetum clandestinum , and speargrass Heteropogon contortus in both seasons, and a mixture of leucaena Leucaena leucocephala and green panic Panicum maximum in the dry season. Each grazing period consisted of at least 21 d, followed by a 3 d collection period. On d 22 CrEDTA was used to estimate RT (182 mg Cr/100 kg BW via the cannula) and RF samples were collected at 0, 4, 8, 12, 16, 24, 28, 32 and 48 h after dosing for Cr analysis. Diet crude protein (CP) and dry matter digestibility (DMD) were estimated by faecal NIRS. Concentration of NH 3 N and volatile fatty acids (VFA) in RF was determined at 0, 8 and 16 h after dosing. Dry season speargrass had the lowest CP (18 and 39 g/kg DM in plucked sample (PS) and estimated by faecal NIRS, respectively) and DMD (49%), which was associated with a low NH 3 N (9 mg NH 3 N/L) and VFA concentration (70 mM) in RF, and much longer RT of Cr (20 h) than the other grasses. The RT of Cr of the other wet season grasses was similar across all forage species (8- to 11 hours). Total VFA in RF was lowest for steers grazing dry season grass, intermediate for grasses in the wet season and highest for steers grazing the legume/grass mix. Speargrass had the highest non-glucogenic:glucogenic VFA. Ryegrass had higher CP (190 g/kg DM) and DMD (68%), but steers grazing this pasture had similar NH 3 N concentration in RF to steers grazing kikuyu and leaucaena/grass mix (above 100 mg NH 3 N /L). Palmitic and stearic acid in RF were much higher than in plucked samples, but all grasses had similar total saturated FA in RF with a greater degree of saturation for ryegrass. A higher CLA c 9, t 11 in RF of steers grazing ryegrass most likely resulted from the linoleic content in the forage and the higher intake of ryegrass resulting in accumulation in RF. Total unsaturated FA (TUFA) content of RF was reduced markedly compared to forage samples with some small differences between species indicating an extensive biohydrogenation despite the grass type and season. It was concluded that RT of Cr in the rumen of cattle grazing wet season grasses was similar across all forage species (8 to 11 hours) and would not result in different times for biohydrogenation within the rumen. [ABSTRACT FROM AUTHOR]

Objective: The aim was to evaluate backgrounding beef steers on oat + ryegrass pastures mixed with vetch and/or using energy supplementation. Methods: A randomized block design with three treatments and three replications was used. The treatments were: grass + supplement (oat + ryegrass + supplementation), legume + supplement (oat + ryegrass+vetch + supplementation) and grass + legume (oat + ryegrass + vetch). A continuous grazing system with a variable stocking rate was used. Twenty-seven intact crossbred steers (1/4 Marchigiana, 1/4 Aberdeen Angus and 2/4 Nellore) aged 7 months old and average weight of 190 kg were used. Steers were supplemented at 1% of the body weight of ground corn. The experiment lasted 84 days, between May and August 2014. Behavioral assessments were performed two times per experimental period, for 24 hours. Results: The forage mass was different between treatments, being greater for steers fed without legume. The accumulation rate, forage allowance, and stocking rate did not differ between treatments due to the adequate adjustment of forage allowance. The final weight of animals, as well as the dry matter intake (kg/d), did not differ between treatments. However, forage intake was higher for non-supplemented animals in relation to supplemented steers. Supplement intake did not alter the total digestible nutrient intake due to pasture quality. Animals fed grass + supplement had higher live weight gain per area than those fed grass + legume. Animals without supplementation spent more time in grazing. Conclusion: Feeding behavior was not altered by mixing with vetch or supplementation. Nonsupplemented animals started the grazing peak earlier and spent more time in grazing than those supplemented; however, the average daily gain was similar between treatments. The live weight gain per hectare was 47% higher in pastures in which the animals received supplementation compared with those mixed with vetch, a consequence of the substitutive effect. [ABSTRACT FROM AUTHOR]

Interest is growing in the use of by-products as economical sources of nutrients that complement grazed grass, particularly at times when grass supply is insufficient to meet the nutritional demands of lactating dairy cattle. The objective of this research was to assess the effect of the amount of by-product inclusion and concentrate feeding rate on pasture dry matter intake, milk production and composition, and N excretion from spring-calving cows grazing summer pasture during mid-late lactation. Forty-eight Holstein Friesian dairy cows were randomly assigned to 1 of 4 dietary treatments in a 2 × 2 factorial design. Cows were grazed in one group on a perennial ryegrass-based sward, with pelleted concentrates offered twice daily during milking over a 63-d experimental period. The dietary treatments were 3 kg of concentrate containing 35% by-products; 6 kg of concentrate containing 35% by-products; 3 kg of concentrate containing 95% by-products; and 6 kg of concentrate containing 95% by-products on a fresh matter basis. The by-products used were soybean hulls, palm kernel expeller, and maize dried distillers grains with solubles, included in equal proportions on a dry matter basis. Pasture dry matter intake (14.5 kg/d) was not affected by the amount of by-product inclusion or feeding rate. By-product inclusion had no effect on milk yield (27.1 kg/d) or milk solids (MS) yield (2.0 kg/d). Cows offered 6 kg of concentrate had a greater milk (+1.6 kg/d) and MS (+0.13 kg/d) yield, consumed more N (+0.08 kg/d), and excreted a lower proportion of N in the milk (0.25 vs. 0.27) and feces (0.39 vs. 0.41) and a higher proportion in the urine (0.39 vs. 0.32) compared with cows offered 3 kg of by-product-based concentrate. In conclusion, by-products can be included at up to 95% of the concentrate fed to cows grazing pasture without affecting pasture dry matter intake, milk production or composition, or N excretion. Cows offered 6 kg of concentrates produced more milk and MS than cows offered 3 kg but had higher urinary N excretion. Economics of this yield response will depend on milk and concentrate prices. [ABSTRACT FROM AUTHOR]

A complete randomized design was used to investigate the effect of increasing pasture species on herbage production, chemical composition and utilization under intensive sheep grazing. Four experimental farmlets were established, namely perennial ryegrass (Lolium perenne) only, receiving 163 kg N ha−1 year−1 (PRG); a perennial ryegrass and white clover (Trifolium repens) sward (PRGWC); a six species sward containing two grasses, two legumes and two herbs (6S); and a nine species sward containing three grasses, three legumes and three herbs (9S), each receiving 90 kg N ha−1 year−1. Ewes (12.5 ewes ha−1) and lambs rotationally grazed each farmlet from turnout post‐lambing until housing. Target pre‐grazing herbage mass (above 4 cm) was 1,200 kg dry‐matter (DM) ha−1, Target post‐grazing sward height was 4 cm for all rotations. Herbage samples were collected for DM yield, botanical and chemical composition determination at each grazing. Annual DM production of the 6S, 9S and PRG swards was similar (10.3, 9.9 and 9.9 ± 0.5 t DM ha−1, respectively) despite differences in N application. The 6S sward, however, had greater annual DM production compared to the PRGWC sward (9.1 t DM ha−1, p < 0.05). Herb proportions decreased in the 6S and 9S swards from 2015 to 2016 (p < 0.05) resulting in increased proportions of grass in these swards (p < 0.05). In conclusion, the PRGWC, 6S and 9S swards produced similar annual herbage DM from lower N inputs to PRG swards; however, maintaining the proportions of herbs is a challenge under intensive sheep grazing. [ABSTRACT FROM AUTHOR]

Increasing herbage dry‐matter (DM) production and utilization on‐farm improves efficiency and sustainability. The objective of this study was to investigate the effect of perennial ryegrass, Lolium perenne L., ploidy and white clover, Trifolium repens L., inclusion on herbage DM production and utilization in an intensive animal grazing system, with high nitrogen (N) inputs (250 kg N ha−1) and a high stocking rate (2.75 livestock units ha−1). The study was a 2 × 2 factorial design, consisting of diploid and tetraploid cultivars sown as grass‐only and grass‐white clover to give four sward treatments (diploid‐only, tetraploid‐only, diploid‐white clover, tetraploid‐white clover). These were evaluated at each grazing occasion (8–10 per year) for 3 years (2014–2016). Tetraploid‐white and grass‐white clover swards had a lower sward density (−9 and −8 kg DM cm−1, respectively) and perennial ryegrass tiller density (−820 and −1,436 tillers m−2, respectively) leading to lower postgrazing sward heights (−0.15 and −0.41 cm, respectively), and maintained a superior nutritive value when compared with diploid‐only and grass‐only swards respectively. White clover inclusion resulted in higher productivity characterized by increased herbage DM production (+1,468 kg DM ha−1), improved nutritive value and increased utilization across the three grazing seasons. Varying sward composition with perennial ryegrass ploidy led to improved nutritive value and favourable grazing characteristics in tetraploid swards. [ABSTRACT FROM AUTHOR]

Irrigated, diverse pastures were managed under normal (grazed to 3.5 cm) or lax (grazed to 5 cm allowing ryegrass seed head development) grazing intensity, with or without mowing (to 3.5 cm), in spring. On the subsequent grazing rotation in summer, an experiment was conducted to investigate the carry-over effects of previous management on herbage regrowth and milk production. Nine groups of three Friesian × Jersey dairy cows each were randomly allocated to three replicates of three treatments: normal grazing (Norm); previously lax managed pastures (Lax); previously lax managed pastures that were pre-graze mown (Mow). Herbage in Mow treatments had a higher ME (p < 0.05) than Lax and Norm (11.7, 11.3 and 11.4 MJ ME/kg DM, respectively). There was no difference in dry matter intake (18 ± 0.30 kg DM/cow/d) or MS production (1.85 ± 0.02 kg MS/cow/d) among treatments. Results of this study indicated that milk production was not altered by grazing management. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess live weight gain, animal behaviour and N excretion in the urine of dairy heifers fed herbs during autumn and spring. Sixty heifers were allocated into five dietary treatments: 100% ryegrass-white clove pasture (100RG/WC); 50% RG/WC + 50% chicory (50CH); 75% RG/WC + 25% chicory (25CH); 75% RG/WC + 25% plantain (25PL); and 50% RG/WC + 50% plantain (50PL). The 100RG/WC had the highest (5.0 times/6 h) and lowest (2.5 times/6 h) urination frequency compared with other treatments in autumn (averaged 3.5 times/6 h) and spring (averaged 4.5 times/6 h), respectively. The heifer LWG in spring was higher in 25CH (1.36 kg/day) than other treatments (averaged 1.10 kg/day). Urinary N concentration was 0.18% and 0.23% in autumn and spring, respectively, across treatments, with no difference between treatments. The study demonstrated inconsistent results of use of chicory and plantain as a mitigation tool to reduce the environmental impact of heifer rearing systems in autumn and spring. [ABSTRACT FROM AUTHOR]

Understanding the economic trade-off between changes in the supplementary feed required and the cost of pasture renovation is important when considering investing in alternative forages. Perennial ryegrass (Lolium perenne L.) is the main pasture species used for dairy production in temperate Australia. Alternatives to perennial ryegrass are grown to complement the seasonal growth pattern of perennial ryegrass, and to potentially increase annual dry matter (DM) yield. A case study analysis of a dairy farm in Gippsland was used to explore the benefits and costs over 15 years when either 0%, 20% or 40% of the milking area was sown to chicory (Cichorium intybus L.), with the balance sown to perennial ryegrass. Chicory was part of a 3-year pasture renovation cycle; in the year of establishment, annual ryegrass was sown in the autumn, with chicory sown in spring, followed by 27 months of production. This was compared with a 5-year renovation cycle of perennial ryegrass. Stocking rates of 3.3 and 2.5 cows/ha were modelled. A whole farm budget approach with stochastic simulation was used to quantify the potential effect on profit and risk. The profitability of growing chicory depended on the balance among (1) savings in supplementary feed costs during summer and autumn, and (2) possible reductions in the overall supply of DMduring winter and early spring, and (3) increased pasture renovation costs. Stocking rate influenced the most profitable percentage of land sown to chicory. When stocking rate was 3.3 cows/ha, sowing 20% of the milking area to chicory returned a net present value (NPV) over 15 years AU$31 000 greater, on average, than did sowing 0% chicory, and AU$46 000 greater than sowing 40% chicory. With 2.5 cows/ha, sowing 40% of the milking area to chicory returned an NPV AU$39 000-AU$102 000 greater, on average, than did sowing either 20% or 0% chicory, respectively. The ratio of perennial ryegrass to chicory had little effect on the variability of NPV. For an individual farm, the most profitable percentage will fluctuate over time with variations in prices, seasonal conditions and management choices. [ABSTRACT FROM AUTHOR]

The development of economic indexing systems for ranking cultivars of forage species requires new knowledge of factors that may influence the scaling of agronomic data collected in controlled, small-plot evaluation trials to whole farm systems. In the case of perennial ryegrass indexing, one such knowledge gap is the effect of growing clover with ryegrass on the relative rankings of different ryegrass cultivars. The objective of the investigation reported in this series was to test whether the relative yield rankings of perennial ryegrass (Lolium perenne L.) cultivars representing the range in phenotypes now available to New Zealand farmers as a result of recent breeding differed when those cultivars were grown in monocultures (as per standard protocols for cultivar yield trialling systems such as the National Forage Variety Trials) versus mixtures of grass and clover. This paper presents the rationale for the investigation by reviewing developments in perennial ryegrass breeding and evaluation in the context of grass-clover relationships in grazed pasture systems. The papers that follow report results from a multi-year, multi-site investigation comparing the yield, nutritive value and other productivity-related variables of eight perennial ryegrass cultivars grown with or without white clover (monoculture versus mixture respectively) at two levels of nitrogen fertiliser. Key considerations in the design of the experiment on which the investigation was based are discussed. [ABSTRACT FROM AUTHOR]

Background: Primary photosensitisation (PS) subsequent to ingestion of the pasture legume Biserrula pelecinus L. (biserrula) has recently been confirmed in grazing livestock. Given the potential utility of this pasture species in challenging climates, a grazing trial was undertaken to examine if both varieties 'Casbah' and 'Mauro' were able to cause photosensitisation in livestock, and if this could be mitigated by grazing in winter, or in combination with other common pasture species. Results: A controlled grazing trial was undertaken in winter in Australia with plots containing a dominant pasture of Biserrula pelecinus L. cv. 'Casbah' or 'Mauro', or mixed biserrula/perennial ryegrass populations. A photosensitisation grading system was established. 167 prime meat ewe lambs were introduced to the plots and monitored twice daily. Mild clinical signs were observed at 72 h on pasture. All animals were removed from biserrula dominant stands at this point. Four animals grazing 'Casbah' dominant pasture rapidly proceeded to severe photosensitisation in the following 12 h. Animals remaining on mixed biserrula/ryegrass stands did not exhibit severe PS but showed an 89% incidence of mild to moderate photosensitisation over the following 14 days. Animals on mixed lucerne showed significantly lower PS score than animals grazing biserrula varieties of any composition. The trial was halted at 14 days as only plots with low biserrula proportion still contained unaffected animals. Necropsy revealed severe multifocal erythematous ulcerations and alopecia of the ear pinnae, severe bilateral periorbital and conjunctival oedema and variably severe subcutaneous facial oedema. No evidence of hepatopathy was present. A diagnosis of acute unseasonal primary photosensitisation caused by biserrula ingestion with no other underlying pathology was confirmed. Conclusions: We report an unseasonal outbreak of acute photosensitisation in sheep grazing Biserrula pelecinus L cvs.'Casbah' and 'Mauro' with exceedingly high morbidity. A grading system is also proposed as a tool for objective and consistent clinical appraisal of future PS outbreaks. This finding expands our definition of seasonal and temporal risk periods for biserrula photosensitisation, and is the first to identify that both commercial cultivars of biserrula can cause primary photosensitisation in sheep. [ABSTRACT FROM AUTHOR]

Dairy cows in experimental grazing herds are often confined for metabolic measurements. The objective of this study was to establish effects of transfer from pasture, to tie-stalls in a metabolism house, then back to pasture, on lying behaviour and locomotion score of lactating cows: Holstein-Friesian (H, n = 16), Jersey (J, n = 16) and H × J (HJ, n = 16). Cows were transferred to tie-stalls on d 1 for 12 days, and were offered freshly cut ryegrass according to herbage allowance (HERB) and genotype: J low = 14; J high = 17; H and HJ low = 16; and H and HJ high = 20 kg DM/d. Lying behaviour was recorded on four days: −2, −1 (Pre-confinement), 3 (Early confinement), 10, 11 (Late confinement), 13 and 14 (Post-confinement) relative to transfer (d 1) using dataloggers, and was also video-recorded during the first 15 h. Locomotion score was recorded on days −4, −3, 12 and 16. No effects of HERB on lying variables were observed during the first 15 h in confinement, but J cows made more lying intentions (21.0 vs. 12.2; P < 0.05) and tended ( P = 0.07) to have a shorter latency to lie. Cows spent less ( P < 0.001) time lying in early confinement (07:22:29 h/d) than on any of the other occasions (9:12:50 h/d). Cows had more ( P < 0.001) and shorter ( P < 0.001) lying bouts in confinement than while at pasture. Low HERB cows spent more time lying than high HERB cows (09:54:55 vs. 09:09:33 h/d; P < 0.01). J had higher locomotion scores than H (9.2 ± 0.2 vs.7.8 ± 0.2; P < 0.001), and tended ( P = 0.09) to have higher scores than HJ (8.5 ± 0.2) cows. Locomotion scores were lowest pre confinement, highest at turnout (d 12), and intermediate after that at pasture (d 16) (7.6 ± 0.2, 9.3 ± 0.2 and 8.6 ± 0.3, respectively; P < 0.01). On transfer to the metabolism house cows showed disrupted patterns of lying although daily lying time returned to levels similar to pasture by late confinement. Confinement also resulted in a short-term deterioration in locomotory ability, which although improving, was still evident 4 days following the cows return to pasture with Jersey cows being more affected than the other genotypes. These findings suggest that longer adaptation periods and temporary release to loafing areas may improve both the validity of data collected and cow welfare. [ABSTRACT FROM AUTHOR]

Ryegrass pasture is characterised as having a high crude protein content (214–298 g/kg DM) but a low fibre content (390–550 g NDF/kg DM). Additional supplementation of energy based concentrates is provided to ensure profitable milk production. The high starch content in these supplements could negatively impact the rumen environment; lowering rumen pH and inhibiting pasture degradability. Dried apple pomace (DAP) is a possible alternative energy source to maize for dairy cows grazing pasture; however, little information is available on the effectiveness of this high fibre by-product for milk production from pastures. The aim of this study was to determine the potential use of DAP as an energy source for Jersey cows grazing ryegrass pasture. Seventy six lactating Jersey cows were blocked according to milk yield, days in milk and lactation number. Cows within blocks were randomly allocated to one of four treatments. Treatments were: NDAP-0% dried apple pomace and 75% maize; LDAP-25% dried apple pomace and 50% maize; MDAP-50% dried apple pomace and 25% maize; HDAP-75% dried apple pomace and 0% maize. Cows received 6 kg as is of the allocated concentrate in the milking parlour daily. Cows of all four treatments strip grazed perennial ryegrass pasture over an area of 8.6 ha. Additionally, four ruminally cannulated cows were used to monitor treatment effect on rumen activity and health. Each cow was randomly allocated to one of four treatments and subjected to a four period crossover. The 4% fat corrected milk yield was lower for cows in treatment HDAP than for cows in treatments NDAP and LDAP, differences ranging between 1.7 and 2.3 kg/day. The milk protein content was lowest for cows in treatments NDAP and MDAP, showing a cubic trend (P = 0.005), with milk fat content increasing as the level of maize substituted by DAP increased. Treatment had no effect on rumen metabolism parameters. Replacing maize with DAP is a viable option for cows grazing ryegrass pasture; however, the decrease in 4% fat corrected milk yield and the potential economic impact should not be overlooked. [ABSTRACT FROM AUTHOR]

Three grazing experiments were carried out in late spring (early lactation), summer (mid-lactation) and autumn (late lactation) to compare the effects of perennial ryegrass cultivar or grass species, sown in binary or multispecies mixtures, on milk yield and nitrogen excretion of dairy cows. Replicated groups of multiparous Holstein Friesian × Jersey cows were offered either a control or high-sugar perennial ryegrass ( Lolium perenne) or tall fescue ( Festuca arundinacea) base grass in a binary mixture with white clover ( Trifolium repens) or in a multispecies mixture with additional legumes, bromegrass ( Bromus willdenowii) and forbs. During each 9-day experiment, botanical composition, milk production and faecal and urine composition were measured. Milk solid ( MS) yield for the control ryegrass, high-sugar ryegrass and tall fescue grass types averaged, respectively, 1.53, 1.64 and 1.70 kg MS cow−1 day−1 for a binary mixture sward, compared with 1.65, 1.54 and 1.53 kg MS cow−1 day−1 for a multispecies sward. Legume content influenced milk production more than the number of species present in a mixture. There was lower urine N concentration from a multispecies sward compared with a binary mixture. Urine N concentration of cows grazing the control ryegrass, high-sugar ryegrass and tall fescue grass types averaged, respectively, 4.6, 5.3 and 6.8 g N L−1 for a binary mixture, compared with 4.1, 3.9 and 3.9 g N L−1 for a multispecies mixture. Feeding dairy cows on multispecies swards containing forbs presents an opportunity to reduce N losses without compromising milk yield. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen balances are useful tools to increase our understanding of soil N processes and the efficiency of plants in taking up animal urine-N. This study aimed to investigate the effect of forage type on the fate of autumn-applied urine-N (700 kg N ha). Methods: In a 17-month lysimeter study the recoveries of N in herbage, leachate, nitrous oxide, and soil + roots (at the end of the trial) were determined for three forage types: perennial ryegrass-white clover (RGWC, Lolium perenne L. -Trifolium repens L.), Italian ryegrass (Italian RG, Lolium multiflorum Lam.), and lucerne ( Medicago sativa L.) under simulated autumn grazing. Results: We recovered 81.5-85.5% of the N applied in the urine. Italian RG had the greatest amount of urine-N recovered in the herbage (49.5%) and the least recovered in leachate (16.8%) making it the most efficient of the three forages for utilizing urine-N. For RGWC, herbage and leachate recoveries were 40.1% and 23.7% , respectively. Lucerne was the least efficient with recoveries of N in herbage and leachate equaling 18.4% and 52.5%, respectively. Conclusions: This study demonstrates that Italian ryegrass could offer benefits in reducing urine-N leaching losses through its ability to take up more urine-N over winter. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has led to explosive growth in the production and consumption of disposable medical masks, which has caused new global environmental problems due to the improper disposal of these masks and lack of effective mask recycling methods. To reduce the environmental load caused by the inability of synthetic plastics to degrade, polylactic acid (PLA) masks, as a biodegradable environmentally friendly plastic, may become a solution. This study simulated the actual degradation process of new PLA masks in different environments by soaking them in various solutions for 4 weeks and explored the influence of the treated PLA fabric fibers on the growth of winter ryegrass. The results show that the weathering degradation of PLA fibers in water mainly occurs through the hydrolysis of ester bonds, and weathering leads to cheese-like and gully-like erosion on the surface of the PLA fiber fabric layer and finally to fiber fracture and the release of microplastics (MPs). The average number of MPs released within 4 weeks is 149.5 items/piece, the particle size is 20–500 µm (44%), and 63.57% of the MPs are transparent fibers. The outer, middle, and inner layers of weathered PLA masks tend to be hydrophilic and have lower mechanical strength. PLA fibers after different treatment methods affect the growth of winter ryegrass. PLA masks are undoubtedly a greener choice than ordinary commercial masks, but in order to confirm this, the entire degradation process, the final products, and the impact on the environment need to be further studied. In the future, masks may be developed to be made from more environmentally friendly biodegradable materials that can have good protecting effects and also solve the problem of end-of-life recycling. Simulation of the actual degradation process of PLA masks and exploration of the influence of mask degradation on the growth of winter ryegrass. [Display omitted] • The degradation of PLA masks is mainly due to the fracture of ester bond. • PLA masks release less microplastics than commonly used commodity masks. • The degradation degree of PLA masks in artificial aquaculture water is higher. • Degradation of PLA masks cause the fragility and hydrophilicity to be strengthened. • The aging environment of PLA fiber fabric inhibits the activities of winter ryegrass. [ABSTRACT FROM AUTHOR]

Decreasing reliance on fertiliser Nitrogen (N) is key to enhancing the sustainability of pasture-based agricultural systems. This study assesses the effect of sward type on annual and seasonal herbage dry-matter (DM) production potential, sown species and unsown species contribution to herbage DM under an intensive dairy-calf to beef system. Three sward types were investigated in a farmlet experiment: Lolium perenne (LP; 205 kg N ha-1 a-1); L. perenne-Trifolium repens (LP-TR); multispecies sward consisting of L. perenne, Phleum pratense, T. repens, Trifolium pratense, Cichorium intybus and Plantago lanceolata (MSS). L. perenne-T. repens and MSS each received 92 kg N ha-1 a-1. Herbage samples were collected for DM production and botanical composition determination at each grazing. Further quadrat sampling was undertaken on three occasions per grazing season (early-, mid- and late-season), to enumerate the unsown species composition of swards and changes in bare ground. Over the course of the two-year study, LP, LP-TR and MSS produced annual herbage DM yields of 9950, 10,650 and 12,600 kg DM ha-1 a-1 respectively, despite reducing fertiliser N application to LP-TR and MSS by 55% compared to LP. The average proportional contribution of grass species to MSS' herbage DM remained constant, the clover content of MSS increased, while the herb content decreased from 2020 to 2021. Seasonally, the proportional contribution of L. perenne and P. lanceolata to MSS' herbage DM declined as the grazing season progressed, the contribution of T. repens and T. pratense increased and that of P. pratense and C. intybus remained similar. In LP-TR, T. repens ' proportional contribution to herbage DM increased from 2020 to 2021, while L. perenne 's proportional contribution declined. Seasonally, the proportional contribution of L. perenne to the herbage DM of LP-TR declined as the grazing season progressed, while the proportion of T. repens ' increased. The contribution of dead plant material to herbage DM increased across all swards in the second year but did not differ between sward types. Sward type did not affect the proportional contribution of unsown species by functional group to herbage DM. These results demonstrate that under a relatively-intensive beef grazing system, MSS receiving reduced N compared to LP monocultures, and the same N compared to LP-TR swards, produce more herbage DM, and do not have a greater weed (unsown species) burden. Overall, our findings demonstrate the potential of MSS to 'produce more while using less', a key requirement of sustainable grazing systems. • The performance of a six species multispecies sward (MSS) was tested for two years. • The performance of MSS was compared to that of a perennial ryegrass monoculture (LP) and LP-white clover mixture (LP-TR). • MSS demonstrate potential for higher DM production from lower N inputs compared with LP. • MSS swards did not show signs of increased unsown species to LP despite a lack of herbicide application. • Legumes persist well, however herbs do not under an intensive, rotationally grazed dairy calf to beef system. [ABSTRACT FROM AUTHOR]

Cool-season forage mixtures are an option for extending the length of the grazing season. Small grains have a different growth distribution than annual ryegrass and may increase livestock gain per area. This 2-yr grazing study tested three small grain-annual ryegrass mixtures: (i) cereal rye (Secale cereale L. 'FL401')--annual ryegrass (Lolium multiflorum Lam. 'Prine'); (ii) oat (Avena sativa L. 'Horizon 201')--annual ryegrass Prine; (iii) triticale (xThticosecale spp. Tri-cal 342')-annual ryegrass Prine. Stocking rate was adjusted, based on herbage allowance, using continuous stocking. Response variables included herbage mass, herbage allowance, herbage accumulation rate, herbage N, herbage in vitro organic matter digestibility (IVOMD), botanical composition, average daily gain (ADG), grazing days, stocking rate (SR), gain per area, and blood urea N (BUN). Seasonal and annual variation occurred for most of the responses, but total season animal production was similar among mixtures. The ADG in 2014 was 0.90 and 0.85 kg head-1 d-1 in 2015. Stocking rate varied among mixtures within sampling dates and years, but season-long average SR was similar among mixtures. Total season animal gain was 367 kg body weight (BW) ha-1 in 2014 and 313 kg BW ha-1 in 2015. Small-grain species and varieties resulted in different growing curves, with FL401 cereal rye being the earliest variety in the present study. Oat and triticale demonstrated a more evenly distributed growth rate along the season, facilitating the adjustment of the stocking rate and grazing management. [ABSTRACT FROM AUTHOR]

To clarify the effect of digesta weight in the reticulorumen on diurnal and seasonal fluctuations in herbage intake, six ruminally cannulated, non-lactating dairy cows were grazed on perennial ryegrass/white clover pasture during morning and evening sessions in spring and autumn. The digesta weight of fresh matter, dry matter (DM) and fiber in the reticulorumen at the beginning and the end of each grazing session was lower in spring than in autumn ( P < 0.01). Although the digesta weight was similar between the sessions at the beginning of grazing, it was greater for the evening than for the morning at the end of grazing ( P < 0.01). The large particles proportion in the digesta was lower for the morning than the evening ( P < 0.01), and it was lower in spring than in autumn ( P < 0.01). The concentrations of volatile fatty acids in rumen fluid were generally higher in spring compared with autumn. The herbage DM intake during the evening was greater compared with the morning in both seasons ( P < 0.01). However, there was no difference in herbage DM intake between seasons. The results showed that the rumen digesta fill was not the sole factor explaining diurnal and seasonal variation of herbage intake in grazing dairy cows. [ABSTRACT FROM AUTHOR]

This study aimed to clarify diurnal fluctuations of herbage intake, ruminal fermentation of herbage carbohydrates and proteins, and digesta particulate weight in the rumen of grazing dairy cows. Six ruminally cannulated, non-lactating dairy cows were grazed on perennial ryegrass/white clover pasture either in the morning (04.00 to 08.00 hours) or the evening (16.00 to 20.00 hours). Cows grazed in the evening spent more time ( P < 0.01) and consumed more herbage ( P < 0.01) compared with cows grazed in the morning. Higher ( P < 0.05) daily mean concentrations of total volatile fatty acid, propionate and n-butyrate in rumen fluid were observed for cows grazed in the evening compared with cows grazed in the morning. Although cows grazed in the evening ingested more crude protein compared with cows grazed in the morning, no significant difference in NH3-N concentration in rumen fluid was observed between them. The ratio of purine-derivative concentration to creatinine concentrations was higher ( P < 0.01) in the urine of cows grazed in the evening than in cows grazed in the morning. These results clearly indicated that evening grazing was advantageous for dairy cows compared with morning grazing, in terms of ruminal fermentable energy intake and nitrogen utilization efficiency. [ABSTRACT FROM AUTHOR]

The inclusion of grazed pasture in dairy feeding systems based on a total mixed ration (TMR) reduces feed costs, benefits herd health, and reduces environmental impact. The present study aimed to evaluate the effect of ryegrass pasture combined with a partial TMR on enteric methane emissions, dry matter intake (DMI), and performance of dairy cows from mid to late lactation. The experimental treatments included 100% TMR (control), partial TMR + 6 h of continuous grazing (0900-1500 h), and partial TMR + 6 h of grazing that was divided into 2 periods of 3 h each that took place after milking (0900-1200 h; 1530-1830 h). Twelve F1 cows (Holstein × Jersey; 132 ± 44 DIM) were divided into 6 lots and distributed in a 3 × 3 Latin square design with 3 periods of 21 d (15 d of adaptation and 6 d of evaluation). Ryegrass (Lolium multiflorum Lam.) pasture was used, and the TMR was composed of 80% corn silage, 18% soybean meal, and 2% mineral and vitamin mixture, based on dry matter. The same mixture was used for cows with access to pasture. The total DMI, milk production, and 4% fat-corrected milk were similar for all cows; however, the pasture DMI (7.4 vs. 6.0 kg/d) and grazing period (+ 40 min/d) were higher in cows that had access to pasture for 2 periods of 3 h compared with those that grazed for a continuous 6-h period. Methane emission was higher (656 vs. 547 g/d) in confined cows than in those that received partial TMR + pasture. The inclusion of annual ryegrass pasture in the diet of dairy cows maintained animal performance and reduced enteric methane emissions. The percentage of grazed forage in the cows' diet increased when access to pasture was provided in 2 periods after the morning and afternoon milking. [ABSTRACT FROM AUTHOR]

There is interest in the reincorporation of legumes and forbs into pasture-based dairy production systems as a means of increasing milk production through addressing the nutritive value limitations of grass pastures. The experiments reported in this paper were undertaken to evaluate milk production, blood metabolite concentrations, and forage intake levels of cows grazing either pasture mixtures or spatially adjacent monocultures containing perennial ryegrass (Lolium perenne), white clover (Trifolium repens), and plantain (Plantago lanceolata) compared with cows grazing monocultures of perennial ryegrass. Four replicate herds, each containing 4 spring-calving, cross-bred dairy cows, grazed 4 different forage treatments over the periods of early, mid, and late lactation. Forage treatments were perennial ryegrass monoculture (PRG), a mixture of white clover and plantain (CPM), a mixture of perennial ryegrass, white clover, and plantain (RCPM), and spatially adjacent monocultures (SAM) of perennial ryegrass, white clover, and plantain. Milk volume, milk composition, blood fatty acids, blood β-hydroxybutyrate, blood urea N concentrations, live weight change, and estimated forage intake were monitored over a 5-d response period occurring after acclimation to each of the forage treatments. The acclimation period for the early, mid, and late lactation experiments were 13, 13, and 10 d, respectively. Milk yield (volume and milk protein) increased for cows grazing the RCPM and SAM in the early lactation experiment compared with cows grazing the PRG, whereas in the mid lactation experiment, milk fat increased for the cows grazing the RCPM and SAM when compared with the PRG treatments. Improvements in milk production from grazing the RCPM and SAM treatments are attributed to improved nutritive value (particularly lower neutral detergent fiber concentrations) and a potential increase in forage intake. Pasture mixtures or SAM containing plantain and white clover could be a strategy for alleviating the nutritive limitations of perennial ryegrass monocultures, leading to an increase in milk production for spring calving dairy cows during early and mid lactation. [ABSTRACT FROM AUTHOR]

Perennial ryegrass ( Lolium perenne L.) evaluation trials are often conducted under simulated grazing to identify the most productive cultivars. It is unclear whether simulated grazing identifies the most productive cultivar for animal-grazed swards. Ten cultivars were established as plots and managed concurrently under simulated grazing ( SG), animal grazing ( AG) and conservation ( CON). The experiment lasted 3 years with dry-matter ( DM) off-take, digestibility, tiller density and ground-cover score recorded in all years. A good relationship existed between DM off-take under SG and CON ( R2 = 0·73). The relationship between SG and AG was strongest in year 2 and 3 ( R2 = 0·53 and 0·55 respectively). High DM production was observed in SG swards in year 1; this was weakly related to the DM production of the AG sward. Across the 3 years, the CON treatment had higher yields than either of the other two treatments and was poorly correlated to DM yield under AG, confirming that cultivars should be evaluated under a similar defoliation frequency to their intended use. Tiller density declined quickest under CON and slowest under AG. Some reranking of cultivars occurred between defoliation managements. The results show that simulated grazing is a useful indicator of DM yield performance of animal-grazed swards. [ABSTRACT FROM AUTHOR]