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• Red clover inclusion to a grass sward improved pre-weaning lamb performance. • Clover or herb inclusion to a grass sward improved post-weaning lamb performance. • Days to slaughter was reduced by grazing binary sward types. • Ewe performance was largely similar across all sward types studied. Ireland's competitive advantage in sheepmeat production is based on the efficient and cost effective production and utilisation of pasture. The objective of this study was to assess the influence of binary mixtures of perennial ryegrass (Lolium perenne L.) plus a companion forage on ewe and lamb performance at pasture. Five sward mixtures were compared, namely; i) perennial ryegrass (Lolium perenne L.;PRG), ii) PRG plus white clover (Trifolium repens L.;PRG + WC), iii) PRG plus red clover (Trifolium pratense L.;PRG + RC), iv) PRG plus plantain (Plantago lanceolate L.;PRG + Plan) and v) PRG plus chicory (Chicorium intybus L.;PRG + Chic). Five farmlets with one sward treatment assigned to each were established which 23 ewes plus their lambs grazed from March to December for the years 2018 to 2021 inclusive. Farmlets were rotationally grazed, stocked at 11.5 ewes/ha and received 130 kg nitrogen/ha/year. Lambs were weaned on average at 15 weeks of age. Post-weaning a leader-follower grazing system was implemented with lambs grazing ahead of the ewes. Post weaning, lambs were weighed fortnightly and drafted at a live weight of 42 kg in June and increasing by 1 kg per month thereafter to produce a target carcass weight of 20 kg. Results show that lamb lifetime average daily gain (ADG) was greater for lambs grazing all binary sward mixtures relative to grazing PRG. Relative to PRG, lamb lifetime ADG was increased by between 17 g/day (PRG + Plan; P < 0.01) to 31 g/day (PRG + RC, and PRG + Chic; P < 0.001) and subsequently the number of days required to reach slaughter (DTS) was reduced by between 15.8 days (PRG + Plan; P < 0.01) to 28.6 days (PRG + RC; P < 0.001) with the addition of a companion forage. As a result of lower DTS, the average total number of anthelmintic treatments administered per lamb was significantly reduced for lambs grazing on all of the binary sward mixtures relative to PRG (P < 0.001). Scanned litter size and ewe milk yield were similar across all sward types as were ewe body weight (BW) and body condition score (BCS) from mating up until 6 weeks post-lambing (P > 0.05). Of the ewes retained from one production year to the next, those grazing PRG + WC, PRG + RC and PRG + Plan had a greater BW than those grazing PRG at the second mating event (P < 0.05), whilst, PRG + RC, PRG + Plan and PRG + Chic ewes had a greater BCS than PRG ewes (P < 0.05). These results suggest the suitability of binary sward mixtures under an intensive sheep grazing system to improve ewe and lamb performance at pasture. [ABSTRACT FROM AUTHOR]

Highlights • Effects of including plantain into ryegrass-clover silage was tested in dairy cows. • Milk yield was the same as with a maize-silage based total mixed ration. • The proportion of n -3 fatty acids was highest in milk fat of cows fed plantain. • The excretion of rumenic acid with the milk was promoted by ensiled plantain. • Adding plantain to the silage did not improve the nitrogen use efficiency. Abstract The effect of plantain (Plantago lanceolata L.) ensiled with ryegrass and red clover (GCP) on the milk fatty acid (FA) profile and nitrogen utilization of dairy cows was tested. Diet GCP was compared to diets based on ryegrass (G), ryegrass and red-clover silage (GC) and total mixed rations (TMR) composed of maize silage, soybean meal and hay (760, 150 and 90 g/kg dry matter (DM), respectively). Cows fed grass-silage diets were supplemented with 3 kg/day of wheat resulting in forage-to-concentrate ratios (DM basis) of 79:21, 85:15 and 86:14 for G, GC and GCP diets, respectively. On average per kg DM, diet G was composed of 790 g ryegrass, diet GC of 577 g ryegrass, 12.3 g blue grass, 218 g red clover, 37.4 g white clover and 5.54 g other species. Diet GCP contained 352 g ryegrass, 127 g red clover, 22.8 g white clover, 7.31 g dandelion and 351 g plantain per kg DM. In a completely randomized design, 24 multiparous dairy cows were fed one of the experimental diets during 13 days of adaptation and 7 days of sampling. The yields of energy-corrected milk (ECM) (27.1 kg/day) and milk protein (910 g/day) of cows fed diet GCP were higher than those of cows fed diet G (20.2 kg ECM/day, 680 g milk protein/day), but did not differ from those of cows fed diet GC or TMR. Urinary nitrogen (N) excretion relative to N intake and relative to total manure N did not differ between treatments. Utilization of dietary N for milk N formation (g/kg) was lowest for diets GCP (251) and GC (257), highest for diet G (357) and intermediate for diet TMR (313). The proportion of polyunsaturated FA in milk fat was highest for cows fed GCP followed by GC, G and TMR. The ratio of n -6 to n -3 FA was lower for diet GCP (1.5:1) compared to G (2.5:1) and TMR (5.7:1). Compared to G, GC and TMR, the cows fed GCP had a higher secretion of 18:1 trans -11 and 18:2 cis -9, trans -11 in the milk relative to dietary 18:3 n -3 + 18:2 n -6 consumed. In conclusion, increasing botanical diversity in the diet by adding plant species from another functional group, as done when switching from diet G to GC to GCP, did not improve N utilization but did lead to distinctly different milk FA profiles, especially when compared to a maize-silage based diet. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of a sensory additive, incorporated into a starch-based concentrate, on milk production and composition and grazing behavior in pasture- fed dairy cows. Forty-five Holstein cows were used in 15 incomplete 3 × 2 Latin squares conducted concurrently with 3 treatments and 2 periods of 28 d At the beginning of the study, cows averaged 60 ± 17.1 d in milk, 2.2 ± 1.51 parity, 27.5 ± 4.52 kg/d of milk, and 504 kg ± 61.9 of BW (mean ± SD). Cows were assigned to the 15 squares by parity, milk yield, d in milk, and BW and within squares randomly assigned to 3 concentrate treatments that were 1 kg/d of a mineral concentrate (MC), 7 kg/d of a starch-based concentrate (CC), and 7 kg/d of CC supplemented with 30 g/d of a sensory additive (PEC; ProEfficient, Lucta SA, Barcelona, Spain). Cows grazed a perennial ryegrass pasture ( Lolium perenne L.) offered at a daily allowance of 30 kg of DM per cow. Supplementation with the starch-based concentrate increased ( P < 0.05) milk yield 4.4 kg/d compared with MC (24.3 .vs. 28.7 kg/d), whereas cows supplemented with PEC produced more ( P < 0.05) milk and energy-corrected milk than CC cows (0.6 and 1.6 kg/d, respectively). As a result, milk response to concentrate supplementation (kg milk/kg concentrate) was improved by PEC. Additionally, PEC increased ( P   <  0.05) milk protein percentage (3.74 vs. 3.43%) and yield (1.08 vs. 0.98 kg/d) compared with CC. Concentrate supplementation increased ( P   <  0.05) total DMI, but reduced ( P   <  0.05) total daily grazing time (GT) and biting rate (BR) in the evening. Compared with CC, PEC did not affect ( P > 0.05) total and pasture DMI but increased ( P   <  0.05) GT during the first 2 h after the a.m. milking as well as BR and ruminating time during the diurnal hours. The plasma concentration of active ghrelin was similarly reduced ( P   <  0.05) by CC and PEC after 2 h of grazing. In summary, supplementation of a starch-based concentrate with a sensory additive improved milk and protein responses of dairy cows grazing a ryegrass pasture. [ABSTRACT FROM AUTHOR]

• Multispecies increased forage intake and milk production of dairy cows. • Urinary N% was 20% lower when cows consumed multispecies. • Cows offered clover forages had a higher N intake and lower N use efficiency. • Perennial ryegrass resulted in the highest milk and N use efficiency. The objective of this experiment was to assess the impact of forage type on the DMI and milk production of mid-late lactation dairy cows. Perennial ryegrass (Lolium perenne) (PRG), PRG and white clover (Trilfolium repens) (PRGWC) and multispecies forage containing PRG, timothy (Phleum pratense), WC, red clover (Trifolium pratense), chicory (Cichorium intybus), and plantain (Plantago lanceolata) (MULTI), were compared using 24 cows in a three-period Latin square changeover design experiment. Cows were acclimatized to dietary treatments for 14 days, before entering a 21-day sampling period. Animals were housed indoors throughout the experiment, with access to forage treatments via computerized feeding boxes that recorded daily forage fresh weight intake and feeding behavior. Forage was harvested using a zero-grazer and feed boxes filled throughout the day. Forage dry matter was determined daily and forage DMI subsequently calculated. Milk yield (MY) was recorded daily, with milk composition (fat, protein, lactose) measured weekly. Once per sampling period, blood and rumen samples were collected. The partitioning of dietary nitrogen into milk, feces and urine was assessed for 6-days in each sampling period. Data was analyzed in SAS using PROC MIXED and checked for normality using UNIVARIATE. Forage botanical composition changed from period 1 to period 2 and 3, leading to significant differences in chemical composition between periods. Despite this, dry matter intake was consistently higher (P <0.05) for MULTI (20.14 kg DM) and PRGWC (18.30 kg DM) compared to PRG (17.06 kg DM). Offering cows MULTI increased daily MY (21.20 kg/d; P <0.001) compared to PRG (20.28 kg/d) and PRGWC (20.19 kg/d). Cows offered PRG made fewer visits to the feed box (P <0.001) and had a reduced meal size (kg/visit) (P <0.001) compared to PRGWC and MULTI. Offering cows MULTI reduced UN concentration (%) by 20% compared to either PRG or PRGWC. Perennial ryegrass resulted in higher dietary nitrogen use efficiency (NUE) compared to PRGWC or MULTI, though this effect was not consistent between periods. These results show that multispecies forages can increase milk production when offered to cows housed indoors. However, despite MULTI resulting in a lower UN concentration, cows offered PRG had a higher dietary NUE, likely due to a lower N intake. [ABSTRACT FROM AUTHOR]

• Multispecies had a higher dry matter degradability than grass/grass-clover forages. • Rumen pH was below 6.0 for longer when cows consumed multispecies. • Perennial ryegrass-white clover resulted in higher rumen ammonia throughout the day. • Multispecies can support milk production but may result in lower milk fat. An experiment was conducted to compare the rumen fermentation and degradability of three forage treatments. A perennial ryegrass (PRG; Lolium perenne), perennial ryegrass and white clover (Trifolium pratense) (PRGWC) and multispecies forage (MULTI), containing two grass species; perennial ryegrass and timothy (Phleum pratense); two clover species; white clover and red clover (Trifolium repens); and two herb species; chicory (Cichorium intybus) and plantain (Plantago lanceolata), were compared. Six rumen fistulated lactating dairy cows were used in a replicated 3 × 3 Latin square experiment consisting of 3 periods lasting 21-days. Cows were allowed ad libitum access to fresh forage and offered 2.71 kg DM concentrate each day. During days 1 – 14 of each period, cows were acclimatized to dietary treatments before entering a 7 – day sampling period. Indwelling rumen pH probes were inserted into the rumen of each cow on day 15 and 16. Rumen fluid samples were taken on day 18 every 2 h for rumen volatile fatty acid and ammonia nitrogen (NH 3 N) analysis. Forage dry matter (DM) and crude protein (CP) degradability was assessed via in sacco incubation beginning on day 19 of each period. Treatment had no effect on dry matter intake (DMI) or milk yield. There was no difference in mean rumen pH between treatments. The rumen pH of cows offered MULTI was below pH 6.0 for a higher percentage of time than the other treatments, however the concentration of acetic acid in the rumen of cows was similar between treatments. Effective degradability (ED) of DM was higher (P = 0.003) for MULTI (0.77) compared to PRG (0.68) and PRGWC (0.66). The soluble CP fraction of MULTI and PRGWC was significantly lower than that of PRG (P = 0.007), though PRGWC had the highest rumen ammonia concentration of all treatments (P = 0.002). MULTI had the highest ED and rate of DM degradation in the rumen, and lowest soluble CP of all treatments. Multispecies forages can support milk production in lactating dairy cows; however, care must be taken to ensure adequate dietary NDF due to the low fiber concentration and highly degradable nature of the forage. [ABSTRACT FROM AUTHOR]

• Beef production in subtropical areas is mainly based in extensive grazing systems. • What is the impact of increasing levels of corn on performance in finishing steers? • Highest forage intake was observed in steers supplemented at 0.4% BW. • Lowest average daily gain was observed in steers supplemented at 0.1% BW. • Corn supplementation from 0.6% to 0.8% BW improves performance and carcass variables. Beef production in subtropical areas is mainly based on extensive grazing systems. During the winter, a drop in the forage quantity is common, energy supplementation may help maintain desired production levels. To measure the effect of increasing levels of corn supplementation on the individual forage intake and feed efficiency of finishing steers, we conducted a 99-d experiment during the winter-spring season in Uruguay. Sixty Aberdeen Angus steers (average BW 464.0 ± 29.7 kg) with access to the same sward of ryegrass (Lolium multiflorum Lam.) were managed under a strip-grazing system (sward height post-grazing: 5 cm) and access to an automated supplement feeder until slaughter. Steers were blocked by BW and previous supplement intake and randomly assigned to one of four groups of 15 animals: control (CON, 0.1% BW of corn), low supplementation (LS, 0.4% BW of corn), moderate supplementation (MS, 0.8% BW of corn), and high supplementation (HS, 1.2% BW of corn). Corn was pelleted with TiO 2 to estimate fecal production. Diet digestibility was estimated with acid-insoluble ash concentration. The average daily forage allowance was 3.6 kg DM/100 kg BW per day. Supplement intake was 0.5, 1.8, 3.6, and 4.3 kg DM/d for CON, LS, MS, and HS group, respectively. Corn added at 0.4% BW resulted in a greater (P ≤ 0.01) forage intake than other treatments. A quadratic response was observed for forage (P ≤ 0.05) and total diet (P ≤ 0.01) intake to increasing rations of supplements. Total diet digestibility was greater (P ≤ 0.01) for CON and LS steers than for those from MS and HS; and an inverse, linear relationship with supplementation levels was observed (P ≤ 0.01). Steers grew faster with increasing amounts of supplementation (P ≤ 0.01) in comparison to CON cattle, responding quadratically (P ≤ 0.05) to added corn. Cattle from the CON group showed the lowest hot carcass weight (P ≤ 0.01). Finishing cattle on ryegrass pasture (low post-grazing sward height) using 0.6 to 0.8% BW of corn supplementation is the best option to obtain a better intake, performance, and carcass weight, being an alternative to reduce days on fattening and/or the cost of feeding animals. [ABSTRACT FROM AUTHOR]

Thirty-six 12-month-old hill hoggets were used in a 2 genotype (18 Scottish Blackface vs. 18 Swaledale×Scottish Blackface)×3 diet (fresh vs. ensiled vs. pelleted ryegrass) factorial design experiment to evaluate the effects of hogget genotype and forage type on enteric methane (CH 4 ) emissions and nitrogen (N) utilisation. The hoggets were offered 3 diets ad libitum with no concentrate supplementation in a single period study with 6 hoggets for each of the 6 genotype×diet combinations (n=6). Fresh ryegrass was harvested daily in the morning. Pelleted ryegrass was sourced from a commercial supplier (Aylescott Driers & Feeds, Burrington, UK) and the ryegrass silage was ensiled with Ecosyl ( Lactobacillus plantarum, Volac International Limited, Hertfordshire, UK) as an additive. The hoggets were housed in individual pens for at least 14 d before being transferred to individual respiration chambers for a further 4 d with feed intake, faeces and urine outputs and CH 4 emissions measured. There was no significant interaction between genotype and forage type on any parameter evaluated. Sheep offered pelleted grass had greater feed intake (e.g. DM, energy and N) but less energy and nutrient apparent digestibility (e.g. DM, N and neutral detergent fibre (NDF)) than those given fresh grass or grass silage ( P <0.001). Feeding pelleted grass, rather than fresh grass or grass silage, reduced enteric CH 4 emissions as a proportion of DM intake and gross energy (GE) intake ( P <0.01). Sheep offered fresh grass had a significantly lower acid detergent fibre (ADF) apparent digestibility, and CH 4 energy output (CH 4 -E) as a proportion of GE intake than those offered grass silage ( P <0.001). There was no significant difference, in CH 4 emission rate or N utilisation efficiency when compared between Scottish Blackface and Swaledale × Scottish Blackface. Linear and multiple regression techniques were used to develop relationships between CH 4 emissions or N excretion and dietary and animal variables using data from sheep offered fresh ryegrass and grass silage. The equation relating CH 4 -E (MJ/d) to GE intake (GEI, MJ/d), energy apparent digestibility (DE/GE) and metabolisability (ME/GE) resulted in a high r 2 (CH 4 -E=0.074 GEI+9.2 DE/GE−10.2 ME/GE−0.37, r 2 =0.93). N intake (NI) was the best predictor for manure N excretion (Manure N=0.66 NI+0.96, r 2 =0.85). The use of these relationships can potentially improve the precision and decrease the uncertainty in predicting CH 4 emissions and N excretion for sheep production systems managed under the current feeding conditions. [ABSTRACT FROM AUTHOR]

• Varying diet allocation sequence can increase intake compared to repeated diet allocation. • Varying diet allocation reduced the day-to-day coefficient of variation of intake compared to repeated diet allocation. • Intake is affected by more than the primary diet composition. The effect of repetitive allocation of a fresh forage diet or varying the availability of diet components on the dry matter intake (DMI) and rumen characteristics of sheep is not fully understood. To determine if repeated feed allocation affected DMI and rumen characteristics, 21 Coopworth rams were allocated to one of three treatments: repetition of ryegrass (Lolium perenne L. ; RR), repetition of a mix (RM) of ryegrass, alfalfa (Medicago sativa L.), chicory (Cichorium intybus L.), or plantain (Plantago lanceolata L.) or varied diet (VD; selection from equal parts DM of two feeds: ryegrass, alfalfa, chicory, or plantain in the AM (0700 h to 1600 h), with the remaining two feeds allocated in the PM (1600 h to 0700 h). All plants by feeding time combinations were randomized by day for the VD. Diets were fed ad libitum for 38 days and DMI was recorded. The VD improved DMI (20 and 10%, respectively) and reduced the day-to-day coefficient of variation of DMI (29 and 23%, respectively) compared with the RR and RM diets. The diet components of each of the diverse diets (RM and VD) resulted in a greater percentage of the rumen volatile fatty acids (VFAs) being comprised of butyrate and valerate. Further research is required to determine if this difference in DMI was the result of the ability to choose between different feeds or if it was the temporal variation in feed availability. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the effect of timing of pasture allocation on performance, feeding behavior, rumen function and plasma and urine metabolites of early-lactation dairy cows in autumn, strip-grazing a perennial ryegrass sward. Forty-two Holstein Friesian cows were randomly allocated to one of the following treatments: Pasture strips allocated daily at either 10:00 h (AM-ALL), 16:50 h (PM-ALL) or twice a day at 10:00 and 16:50 h (AM–PM). Herbage allowance was 21 kg DM/cow/day for all treatments. All cows received a daily allocation of concentrate and grass silage, 3.0 and 3.2 kg DM per cow, respectively. Herbage chemical composition differed amongst treatments, as dry matter and WSC contents were greater in PM-ALL than in AM-ALL and AM–PM. Milk yield tended to be greater with PM-ALL ( P =0.06) compared with AM-ALL and AM–PM. The concentration of protein tended to be greater with AM–PM ( P =0.09) compared with PM-ALL and AM-ALL. Protein and urea concentrations in milk did not differ among treatments. Daily grazing, ruminating and idling times were similar among treatments ( P >0.05). During the first 2 h, cows in AM-ALL grazed 30 and 15 min longer than cows in AM–PM and PM-ALL treatments ( P <0.05). Herbage disappearance was greater ( P =0.003) in PM-ALL compared with AM-ALL and AM–PM. Treatment did not affect rumen fermentation metabolites, except for the concentration of propionic acid, which was 3% lower for cows in AM–PM compared with AM-ALL and PM-ALL cows. Cows in PM-ALL had lower concentration of urea in plasma 0.88 and 0.68 mmol/L less compared with cows in AM-ALL and AM–PM ( P =0.04). Concentrations of urinary metabolites were not affected by treatment. These results suggest that timing of pasture strip allocation alters nutrients supplied by herbage to cows, but has only a small effect on herbage dry matter intake. Consequently, allocating the daily pasture strips in the afternoon would tend to increase milk production compared with allocations during the morning (~3) and twice a day (4.4%). [ABSTRACT FROM AUTHOR]

Accurate grass organic matter digestibility (OMD) values are required for intake prediction, for calculating metabolisable protein and ultimately to accurately formulate diets. The three objectives of this study were: (i) to compare the neutral detergent cellulase (NDC)- and pepsin cellulase (PC)-predicted OMD to in vivo OMD; (ii) to compare the NDC method to the PC method for accurately estimating grazed grass OMD and (iii) to compare the effect of sample preparation on the NDC method results, specifically oven drying samples at 60 °C compared to freeze drying at −55 °C. Data consisted of 34 forage grass samples on which OMD was measured in vivo using the total faecal collection method in sheep (OMD INVIVO ). The grass samples were also analysed in vitro in triplicate. For the NDC method the samples were oven-dried at 60 °C for 48 h or were freeze-dried at −55 °C for 1 week. The PC method samples were oven-dried at 60 °C for 72 h. The NDC organic matter solubility (OMS) results were inserted into the equation developed by Stakelum et al., (1988. Irish J. Agric. Res. 27, 104–105) to give OMD NDC . The OMS results from the PC method were inserted into the equation developed by Aufrère et al., (2007. INRA Prod. Anim. 20, 129–136) to give OMD PC . The comparison between OMD PC 60 (mean±standard error) (0.708±0.0361; n =34) and OMD INVIVO (0.719±0.0361) showed that there was a tendency for the two methods to give different results ( P =0.06). The comparison between OMD NDC FD (0.740±0.0049; n =18) and OMD INVIVO (0.764±0.0063) showed that the two methods gave different results ( P <0.01). The comparison between OMD NDC 60 (0.680±0.0265; n =34) and OMD INVIVO (0.719±0.0361) showed that the two methods gave different results ( P <0.05). The positive correlation with OMD INVIVO suggested that OMD NDC FD, OMD NDC 60 and OMD PC 60 were able to predict OMD INVIVO of perennial ryegrass grazed swards. The comparison between OMD NDC FD (0.740±0.0049) and OMD PC 60 (0.746±0.0109) showed that the two methods gave similar results ( P >0.05). The comparison between OMD NDC 60 (0.680±0.0230) and OMD PC 60 (0.708±0.0230) showed that the two methods tended to give different results ( P =0.06). To improve the relationship between OMD INVIVO and OMD NDC FD, and between OMD INVIVO and OMD NDC 60 , future work should expand the number of grass samples, the months of the year over which samples are collected and the range of chemical composition and OMD INVIVO of the samples. Sample preparation method had an effect on the NDC-predicted OMD results as OMS NDC FD differed to OMS NDC 60 and OMD NDC FD differed to OMD NDC 60 . This indicated that specific correction (regression) equations must be used for specific sample preparation methods. [ABSTRACT FROM AUTHOR]

• A low pre-grazing herbage mass (1500 kg DM/ha) reduces steer live weight gain. • A low pre-grazing herbage mass (1500 kg DM/ha) reduces live weight gain/ha. • Increasing grazing rotation cycle length increases annual herbage growth. • During finishing, concentrates are required to meet carcass fatness specification. The objective was to determine the effect of pre-grazing herbage mass (PGHM) on herbage production and nutritive value, intake and growth of suckler-bred steers in a rotational stocking system, and the residual effects on intake, growth and carcass traits during subsequent indoor finishing. A total of 108 yearling steers previously offered grass silage indoors over 105 days were assigned to one of two PGHM (1500 – low (L) or 2000 – high (H) kg dry matter (DM)/ha; > 4 cm) treatments. Steers (ca. 345 kg at turnout to pasture in spring) rotationally grazed perennial ryegrass (Lolium perenne) dominant pasture in 12 groups of 9 for 203 days. At the end of the grazing season they were housed indoors and offered either (1) grass silage only or (2) grass silage + 3.17 kg concentrate DM/head daily for 136 days until slaughter at 24 months of age. Annual herbage production was higher (8427 vs. 7542 kg DM/ha, P < 0.01) for H than L, but there was no difference between treatments in surplus herbage removed as silage due to the tendency for H steers to consume more herbage/ha while grazing (7363 vs. 6479 kg DM/ha, P = 0.08). During the grazing season, compared to L, steers grazing H had a greater estimated herbage DM intake (6.59 vs. 5.93 kg DM/ha, P < 0.001), daily live weight gain (0.81 vs. 0.76 kg, P < 0.01), live weight at the end of the grazing season (553 vs. 539 kg, P < 0.01) and live weight gain/ha (1261 vs. 1206 kg/ha). During the indoor finishing period there was no PGHM × finishing diet interaction, and no residual effect of PGHM on daily live weight gain, but carcass weight tended to be heavier for H (359 vs. 354 kg, P = 0.06) than L. Compared to silage only, the silage + concentrates group had a higher (P < 0.001) total DM and energy intake, feed conversion efficiency, live weight gain, carcass weight and carcass conformation and fat score. In conclusion, grazing the lower PGHM reduced herbage production, steer live weight gain at pasture, overall live weight gain/ha and tended to reduce carcass weight; therefore, under the conditions of this experiment grazing a PGHM of 2000 kg DM/ha is recommended. Removing concentrates from the finishing diet reduced carcass weight and fatness, making it more difficult to finish steers at a commercially acceptable carcass (carcass fat score > 6.0, 1 - 15 scale). [ABSTRACT FROM AUTHOR]

Abstract: Errors due to microbial colonization in the rumen (determined using 15N techniques) on neutral (NDF) and acid (ADF) detergent fibres and on the N bound to both these fractions (NDIN and ADIN, respectively) were evaluated using in situ (experiment 1) and in vivo methods (experiment 2). In experiment 1, the ruminal degradation of Italian ryegrass (Lolium multiflorum Lam.) hay was studied in 6 and 72h incubation residues, as well as in a composite sample (CS) representative of the rumen outflow of undegraded feed particles. The colonization errors of ruminal and duodenal digesta samples derived from a mixed diet were controlled in experiment 2. Three double-cannulated wethers (rumen and duodenum) were used in each study. In experiment 1, mean proportions of microbial-N in all tested fractions increased with the incubation time. The lack of correction for microbial colonization led to inaccuracies in the estimates of fibre fractions and its degradability. These errors were dramatic for NDIN, high for ADIN, moderate for NDF and low for ADF. The 15N enrichments recorded in experiment 2 showed large microbial colonization of NDF and ADF in ruminal and duodenal samples. However, estimates based on adherent bacteria probably overestimate this colonization, because evidence of a large presence of free bacteria was also found in these samples. Direct ADF extraction shows a lower efficiency in eliminating microorganisms than sequential NDF–ADF or NDF procedures. Results demonstrate the need for correcting the microbial colonization to obtain accurate conclusions about the ruminal digestion of cell wall proteins. These errors should also be considered when analyzing NDF using in situ and in vivo techniques. [Copyright &y& Elsevier]

Abstract: The objective of the present study was to test the hypothesis that feeding dried grass from a ryegrass cultivar with high water-soluble carbohydrate (WSC) concentration to dairy cows lowers emissions of enteric methane and urinary nitrogen. This dried grass (here the cultivar ‘AberMagic’) was compared as a forage-only diet to dried grass prepared from a low-WSC cultivar (‘Respect’). Six mid-lactating primiparous Holstein-Friesian dairy cows (19kg milk/cow/day) were subjected to a change-over design in two 26-day experimental periods. In the last 8 days of each period, feed intake, milk yield, fecal and urinary excretion were recorded and samples were taken. During 2 days, methane emissions were measured in open-circuit respiration chambers. The dried grass type had no significant effect on feed intake and milk gross composition. Milk yield was lower for cows fed the dried high-WSC grass. Total enteric methane (g/day) did not significantly differ when cows received dried high-WSC grass (279) instead of dried low-WSC grass (315). Methane expressed as g/kg dry matter intake (19.4 and 20.3 for dried high- and low-WSC grass, respectively), and methane conversion rates (Y m ; 63kJ/MJ of gross energy for both dried grass types) were similar with both dried grass types. The dried high-WSC grass had a lower crude protein concentration compared to the dried low-WSC grass (158 vs. 255g/kg dry matter) resulting in a correspondingly different urinary N excretion (114 vs. 292g/day) and milk urea concentration. A similar effect was found for urinary N proportion of total excreta N. Fecal N excretion and milk N secretion were higher with the dried high-WSC grass. In conclusion, feeding dried high-WSC ryegrass, where WSC mainly replace crude protein, might be helpful in limiting N emissions from dairy cattle husbandry whereas methane emissions seem to remain unaffected. Further studies have to test whether dried high-WSC grass has the same effect when the WSC replace fiber and to address the extent to which favorable effects can be recovered in mixed forage-concentrate diets. [Copyright &y& Elsevier]

Abstract: Two completely randomised experiments compared the impact of different spices, each at 30mg/g substrate DM, on the in vitro dry matter disappearance (IVDMD), methane, ammonia and volatile fatty acids (VFA) from either wheat flour (wheat) (experiment 1) as highly or hay based mixtures (experiment 2) as moderately fermentable substrates. Experiment 1 tested the effects of adding cinnamon, clove, coriander, cumin and turmeric, individually, on the rumen fermentation during their in vitro incubations with wheat for 24h. All spices reduced methane (P<0.05) from wheat as compared to the spice-free wheat (control). Coriander reduced methane more followed by turmeric, cumin and cinnamon than the control. The IVDMD of wheat did not differ for most spices except cinnamon where IVDMD was reduced (P<0.05) as compared to the control. Whilst, rumen ammonia was greatest for cumin (P<0.01) followed by coriander and turmeric, it was lowest for clove (P<0.01). The spices did not affect the pH and total VFA of rumen fluid for wheat. However, the presence of clove reduced acetic acid (P<0.05). Experiment 2 tested the effect of only three (coriander, cumin and turmeric) spices individually or together on the in vitro fermentation of hay based mixtures during 96h of incubation. Whilst all the individual spices or their mixture reduced methane from the hay based mixtures (P<0.05), the extent of this reduction was highest for turmeric, second highest for coriander and lowest for cumin. It appeared that most spices modified methane emission from wheat as a single ingredient or hay based mixtures without having detrimental effect on diet disappearance or fermentation in vitro. However, the extent of this modification depended on the type of a spice and substrate. Therefore, careful selection of a spice to suit specific feeds would be essential before their in vivo use to modify the fermentation efficiency of ruminant diets. [Copyright &y& Elsevier]

Abstract: Grazing low-mass pastures is almost inevitable when extending the grazing season into late winter to reduce feed costs, cows'' performance being potentially affected. An experiment was carried out to estimate the performance, pasture intake (PI) and behavioural adaptation of dairy cows when grazing low-mass pastures at LOW, MEDIUM and HIGH pasture allowances (PA), corresponding to 19, 32 and 46kg OM/cow per day above ground level, respectively. The study took place in the late winter of 2008 on good quality perennial ryegrass/white clover pastures with a mean pasture mass and a pre-grazing platemeter height of 2.3t OM/ha above ground level and 5.8cm, respectively. Each cow was supplemented with 4.4kg OM of maize silage and 2.0kg OM of cereal concentrate. Daily time at pasture was restricted to 9h between the am and pm milkings. Eighteen midlactation Holstein cows (twelve multiparous and six primiparous) were used in a 3×3 orthogonal Latin square design with three consecutive periods of 13days. On average, the cows produced 25.3kg of milk and total OM intake was 14.4kg/d. Pasture OM intake averaged 7.9kg/d and linearly increased from LOW to HIGH (+0.04kg/kg PA). Similarly, milk production per cow (+0.09kg/kg PA) and milk protein concentration (+0.04g/kg per kg increase in PA) linearly increased with increasing PA. Milk fat concentration, on the other hand, decreased by 0.10g/kg per kg increase in PA. The daily grazing time (430min) and the proportion of time spent grazing (79%) were not affected by PA. On average, pasture intake rate was low (19g OM/min) and linearly increased from 16.9g OM/min in LOW to 20.7g OM/min in HIGH. In the present study, the PI was limited even at high PA because of the cumulative effect of the low-mass pasture (low intake rate) and the restricted access time (short grazing time). Consequently, the effect of PA on PI was low. However, the milk production response to variations in PI was high because of the low energy balance recorded in all treatments. [Copyright &y& Elsevier]

Abstract: The short-term behavioral adaptation of cattle to time restrictions at pasture is poorly understood. This research explored the FS behavior of dairy cows during the first grazing session of the day (0800–1200h) in response to daily restriction of time at pasture. Six groups of 8 multiparous Holstein–Friesian cows (470±47kg, 35±9days in milk) were strip-grazed on a perennial ryegrass (Lolium perenne L.) pasture for either 4h after each milking (2×4), one period of 8h between milkings (1×8), or 24h excluding milking times (control, CTL). Daily herbage allowance was 0.07kg DM/kg live weight/day for all treatments. Cows were not fed supplements. Six cows per group were equipped with IceTag 3D motion sensors and GPS collars to measure the total distance walked, and the number of FS per min, and to allow calculation of the step length while eating. Bite rate (bites/min) and eating time (min) were determined for these cows. Bites per FS, velocity of walking while eating (m/min), total number of FS, total distance walked while eating (m), and area explored while eating (area of FS×total number of FS) were calculated. The velocity of walking while eating and the number of FS per min were also determined at 4 fixed times during such a grazing session. No difference in the number of FS per min and bites per FS was found between treatments, although cows in 1×8 had the greatest velocity of walking while eating for the first 200min of the grazing session. Eating step length, velocity of walking while eating, total number of FS, distance walked while eating and area explored while eating were the greatest for cows in 1×8. Cows in CTL showed the lowest values for the total number of FS. The results of this experiment demonstrated that dairy cows reacted to restrictions of time at pasture mainly by changing locomotion behavior (step length, velocity of walking while eating, and distance walked while eating), which led to considerable changes in the area explored while eating. This study of foraging behavior contributes to the understanding of eating and locomotion behavior of dairy cows in response to restrictions of time at pasture. [Copyright &y& Elsevier]

Abstract: An experiment was carried out with sixteen non-pregnant, non-lactating adult Rasa Aragonesa ewes fed different proportions of lucerne and ryegrass hays to validate the use of n-alkanes and NIRS methods to estimate diet composition, intake and digestibility. The effect of two different faecal sampling procedures (daily pool (S1) or rectal spot samples (S2)) was also tested. The faecal concentration of n-alkanes was affected by the sampling procedure, although differences were lower than 12%. Faecal recoveries were not affected by diet, except in the case of C23 (P <0.0001), C28 (P =0.0264) and C33 (P =0.0241), and followed a curvilinear pattern with alkane chain length. Recovery was complete in the case of C29, C31 and C33, which countersigns the usefulness of these internal markers for digestibility and digestive flow studies (especially C31, given its high concentration in most plants). The faecal recoveries of C31 and C32 were not similar, the assumption of identity affecting in an important way the reliability of intake estimates. The NIRS methodology appeared as a promising alternative for predicting diet composition (R 2 of the cross-validation=0.98) and faecal concentration of most natural alkanes, although that was not the case for dosed alkanes. In all cases, the prediction equations obtained from the spectra of the faecal spot samples were better than those obtained from daily pool samples. [Copyright &y& Elsevier]

• Toxicity threshold for ryegrass staggers is lowered the longer perennial ryegrass is fed. • Sub-chronic (>60 day) threshold for lolitrem B is 1554 µg/kg in Angus beef cattle. • Lolitrem B accumulates in fat tissue in a dose- and time-responsive manner. Lolitrem B is a potent tremorgen responsible for the syndrome known as "ryegrass staggers" in livestock consuming perennial ryegrass (Lolium perenne) infected with the endophyte fungus Epichloë festucae var. lolii. We evaluated clinical signs in cattle continuously fed endophyte-infected perennial ryegrass straw at four concentrations of lolitrem B (LB)/ergovaline (EV) (groups: I-2256/638, II-1554/373, III-1012/259 or IV-<300/0 µg/kg LB/EV, n =5-6 steers/group) over 64 days to establish a sub-chronic threshold of toxicity for this mycotoxin; animals were supplemented with 1 kg grain mix/day. Most animals in groups I and II developed clinical signs consistent with ryegrass staggers by day 64; thus, it is recommended that a threshold level of 1554 µg/kg LB should not be exceeded for extended feeding regimens using endophyte-infected perennial ryegrass feed material alone. This toxicity threshold is lower than that observed with shorter feeding periods, i.e. 1800–2000 µg/kg LB when fed for less than 30 days. No clinical signs associated with ergovaline toxicosis (i.e. decreased weekly weight gain) were observed. As adipose tissue appears to be the main compartment where LB is deposited, the concentration of LB and its metabolic derivatives in fat samples was determined at 37 and 64 days. Lolitrem B and three previously defined metabolites bioaccumulated in a dose- and time-dependent manner throughout the feeding experiment in fat tissue, at levels similar to those found in past research. Ratios of metabolites to LB were consistent across time points and dose groups, indicating that the enzyme(s) responsible for LB metabolism were not saturated. In summary, LB toxicity thresholds are dependent upon specificities of the dietary program including the duration feed material is fed, and should be considered when formulating safe livestock feeding regimens. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Two experiments were carried out to compare white clover with red clover as supplementation to ryegrass, in ensiled and fresh form, for differences in nitrogen loss and methane emission by dairy cows. In experiment 1, fresh ryegrass was mixed with fresh white (WF) or red clover (RF) (60/40 on dry matter basis). Experiment 2 involved similar mixed diets in ensiled form (WS and RS, respectively), and two ryegrass silage diets, without (GS) or with supplementary maize gluten meal (600 g protein/kg DM; GS+). Barley was supplemented to meet the calculated requirements for milk production. The type of clover did not affect crude protein (CP) intake in experiment 1. In experiment 2, the highest CP intakes were observed for cows on the GS+ diet (P <0.05), followed by the WS and RS diet, compared to the GS diet. Within experiments, no treatment effects occurred for intake of digestible organic matter, milk and milk protein yield, while milk urea and urine N excretion mostly reflected the differences in CP intake in experiment 2. The highest absolute N excretions (P <0.001) occurred with the GS+ diet, compared to the other diets. Per unit of N intake, a tendency for highest urine N losses with GS+ was still noticeable. The slurry characteristics were not affected by clover type during storage in experiment 1. In experiment 2, initial treatment differences in ammonia-N levels (P <0.01) in the slurry were still observed after 8 weeks of storage. Clover supplementation, but not clover type, slightly enhanced gaseous N losses per cow per day in relation to GS, but not as much as GS+ (+53%). Gaseous N losses relative to milk N yield were slightly lower (P <0.1) with fresh red clover compared to white clover, a trend not apparent in experiment 2 with silages where levels were elevated with GS+. Methane emissions were not affected (P >0.05) either by clover supplementation or by clover type in both experiments. This study illustrates that the white and red clovers investigated were widely similar for their effects on N losses and methane emission in dairy cows. Our findings imply that supplementation of white or red clover to a high-protein ryegrass could enhance nitrogen losses to the environment, and would not be beneficial in terms of reducing methane emissions. [Copyright &y& Elsevier]

Abstract: In this study, the effect of increasing the proportion of concentrate in the diet, on efficiency of feed utilisation, was determined when Holstein–Friesian cows grazed short-rotation ryegrass (Lolium multiflorum) or kikuyu (Pennisetum clandestinum) pastures. The concentrates were energy-dense dairy pellets fed twice-a-day at milking and the roughage component was lucerne hay and the pasture. When cows grazed ryegrass, there was no effect on animal performance as the proportion of concentrate in the diet increased from 0.23 to 0.35 (4.75 to 7.50kg concentrate/cow/day). The substitution rate of concentrates for pasture for the first 1.57kg concentrate/cow/day fed was 0.58 but rose to 1.18 for the next 1.28kg concentrate/cow/day. When cows grazed kikuyu, there was also no effect of increasing the proportion of concentrate in the diet on total dry matter intake (DMI) or milk production. However, there was a substantial increase in the in vivo digestibility of whole diet, pasture and acid detergent fibre (ADF) was observed when the proportion of concentrate in the diet increased from 0.08 to 0.25. However, there was a marked decline in pasture digestibility (72% to 64%), and more so in ADF digestibility (61.3% to 48.4%), as the proportion of concentrate in the diet increased further to 0.29 (5.52kg/cow/day). The intake of kikuyu, when determined by difference between pre- and post-grazing pasture mass, was substantially underestimated compared to the use of the n-alkane technique, and this discrepancy increased as the pasture on offer increased. On both pasture types, the neutral detergent fibre intake, as a % of bodyweight varying from 1.6% to 2.2% for kikuyu and 1.5% to 1.6% for ryegrass was far above the values claimed of 1.2% to restrict intake. The results of this study highlight the limits to the amount of concentrate that can be fed on a typical Australian dairy farm where concentrates can only be fed twice-a-day at milking. The results also provide a more appropriate benchmark for fibre limitation in the ration when cows graze pasture, particularly poorer quality tropical grasses, and this value is well above that found in more intense feeding situations. [Copyright &y& Elsevier]

Abstract: The aim of this study was to assess grazing behaviour, intake, rumen function, milk production and composition of dairy cows grazing perennial ryegrass varieties that were morphologically and chemically similar, but differed in their water-soluble carbohydrate (WSC) concentration. Eight multiparous rumen cannulated dairy cows were offered four varieties of perennial ryegrass under a 1-day strip-grazing system using a 4×4 Latin square design in two consecutive years. Two of the varieties were characterised by a high WSC content (HSV) and the other two varieties had a lower concentration of WSC (LSV). Grazing behaviour was recorded using a solid-state behaviour recorder. Daily intake was estimated using the n-alkane technique. Rumen function was measured using rumen evacuation. As expected the HSV had a higher WSC content (P <0.05) than the LSV with an average difference of approximately 32 g/kg dry matter. The other chemical constituents did not differ significantly between HSV and LSV. The sward surface height, herbage allowance and tensile strength were not significantly different between HSV and LSV. None of the grazing behaviour parameters (eating time, rumination time, bite rate, chewing rate and bite mass) were significantly different between HSV and LSV. Daily dry matter intake (DMI), fibre clearance rate, milk production and milk composition (fat, protein and lactose) were not different between cows grazing the HSV and LSV. At the level of difference in WSC content between the grass varieties reported in this study (32 g/kg), offering dairy cows a high sugar pasture did not influence grazing behaviour and rumen function and was not beneficial in improving DMI, milk yield or in altering the composition of milk. [Copyright &y& Elsevier]

Abstract: In the summers of 2000 and 2001, the effect of six diploid perennial ryegrass (Lolium perenne L.) cultivars on the N utilisation by 12 high productive dairy cows was determined. Experiments were conducted according to a double 3×3 Latin square design; within each Latin square, three cultivars were fed to six cows during three periods of 2 weeks each. Two cultivars had a higher water-soluble carbohydrate (WSC) content than the other cultivars in both years. A higher WSC content was more compensated by a lower neutral detergent fibre (NDF) content than by a lower crude protein content. In both years, dry matter intake (DMI) and milk production (MP) varied only slightly among cultivars and no differences among cultivars were found in the excretion of N in milk (in g/day and as % of N intake). Furthermore, cows fed the two cultivars with elevated WSC content had a lower N intake and this was associated with a lower milk urea N content and urinary N excretion. The small differences in chemical composition among cultivars did not result in significant differences in DMI, MP and N utilisation in dairy cows fed indoors. The results suggest that there is little scope to improve N utilisation of dairy cows at high N fertilization levels by breeding new cultivars. [Copyright &y& Elsevier]

Abstract: The aim of this trial was to evaluate the influence of castration on fatty acid composition of intramuscular fat. Twenty-four bull calves of Mertolenga breed were randomly assigned to two groups: castrates and intact males. Castration was done at weaning (6 to 8 months of age). After weaning, all animals grazed a rye-grass pasture through 1 year and were then placed in a feed-lot and fed a finishing diet. Three animals of each treatment were slaughtered after a period of 0 (pasture only), 50, 100 and 150 days of feed-lot feeding. All the animals were subjected to the same feeding and management regimes. Fatty acid composition of the intramuscular fat was analyzed in samples of muscle Longissimus lumborum taken after 7 days of ageing. After adjustment for equal intramuscular fat, entire males had significant higher values of C17:0, C18:1trans , C18:2n−6, P/S, n −6/n −3 and C18:2n−6/C20:4n−6 ratios and lower values of C16:0 and C18:1cis-9, indicating that castration has an effect on the fatty acid composition of intramuscular fat of Longissimus lumborum. [Copyright &y& Elsevier]

• Mitigating nitrous oxide emissions from ruminant livestock systems is a challenge. • Energetic supplementation decreased nitrogen urinary excretion. • Energetic supplementation decreased nitrous oxide emissions. • Acacia mearnsii extract was not effective to mitigate nitrogen emissions. The nitrogen (N) excreted by grazing animals is the main source of nitrous oxide (N 2 O) emissions in livestock systems, and feeding strategies to mitigate N excretion should be further studied. The objective of this study was to evaluate the effects of ground corn and tannin extract supplementation on mitigating N 2 O emissions from sheep excreta. The emissions factor (EF,% of N excreted, which was emitted as N 2 O N) under the studied conditions were also measured. Two experiments were conducted. In the first one, six Lacaune lambs, with an average BW of 27 ± 3 kg, were distributed in a replicated 3 × 3 Latin square experimental design. The treatments included ad libitum access to ryegrass (Lolium multiflorum Lam.) silage, which contained 21.1 g N/kg DM and was supplemented with 60 g of soybean meal (S), 140 g of ground corn + 60 g of soybean meal (SC) or 140 g of ground corn + 60 g of soybean meal + 40 g/kg Acacia mearnsii tannin extract concentrate (SCT). The daily production of faeces and urine was measured, and samples were collected each day. In the second experiment, urine and faeces were applied to static chambers in the field to determine their N 2 O emissions. Three replicates of type of excreta from each treatment were included. The nitrogen intake was similar between the treatments, with an average of 18 g/day. The faecal N excretion obtained with tannin extract supplementation was 16% higher (P < 0.01) than that obtained with the S and SC treatments. The daily urinary N excretion from the animals administered ground corn supplementation was 12% lower (P < 0.05) than that from the animals that received only soybean meal, whereas the inclusion of tannins did not effectively induce further decreases in urinary N excretion. The faecal EF of the different treatments was similar, with an average of 0.56 g N 2 O N/100 g N. The EF of the urine samples averaged 4.8 g N 2 O N/100 g N. Corn grain supplementation decreased urinary N excretion and N 2 O emissions from sheep excreta, whereas Acacia mearnsii tannin extract did not effectively improve this response. [Display omitted] [ABSTRACT FROM AUTHOR]

• Offering sheep perennial ryegrass (PRG) swards in excess of 3000 kg DM/ha will result in a decrease in voluntary dry matter intake (VDMI). • High herbage mass (HM) PRG contains higher indigestible fibre in the form of NDF (iNDF IV) which reduces VDMI and digestibility • Animals offered Low HM PRG(1000-1500 kg DM/ha) have higher rates of digestion for potentially digestible NDF (pdNDF) • Time of year (grass growth stage) significantly affects the ruminant animals DMI and digestibility of PRG with values lower in autumn than in spring or summer. • In situ iNDF can be used as a predictor of OMD IV for animals offered PRG swards • There is potential to use in situ iNDF to predict VDMI in small ruminants It is essential to have accurate data relating sward herbage mass (HM) to voluntary dry matter intake (VDMI) and in vivo organic matter digestibility (OMD IV) across the year. This will ensure that the production performance of animals grazing differing HM swards can be accurately predicted using in vitro and in situ methods. The objectives of this experiment were to (i) determine the OMD IV and VDMI of sheep offered perennial ryegrass differing in HM throughout the growing season and (ii) evaluate in vitro gas production (IVGP) and in situ indigestible neutral detergent fibre (iNDF IS) as methods of predicting OMD IV. A 3 × 3 Latin square design was used to investigate three HM treatments. The target HM (measured > 4 cm) of perennial ryegrass for the three HM treatments was 1200 kg dry matter (DM)/ha (Low), 2500 kg DM/ha (Medium) and 4000 kg DM/ha (High). The experiment was a Latin square design repeated in three time stages (TS) in 2013 (TS1, TS2 and TS3). A 3 × 2 incomplete Latin square design was used in early spring 2014 (TS4). In TS4 the HM were lower than in the previous TS at 1000 kg DM/ha (Low), 1800 kg DM/ha (Medium) and 2500 kg DM/ha (High). Each experimental period within each TS consisted of a 6 day adaptation phase and 6 day measurement phase; with 12 Texel wether sheep used. Sheep were fed ad libitum to ensure a 10% refusal rate. The interaction between TS and HM treatment had the greatest effect on chemical composition, VDMI and OMD IV. Low HM swards had the greatest VDMI and OMD IV. For each 1000 kg DM/ha increase in HM, OMD IV was reduced by 2.3% on average. This varied from 0.9% in TS4 to 2.7% in TS3. There was no difference between HM treatments in the rate of digestion of digestible NDF using the IVGP technique. In situ indigestible NDF concentration and OMD derived from IVGP (OMD GP) were highly correlated with OMD IV (r2 = 0.901 and 0.895 respectively) and moderately correlated with digestible organic matter intake (DOMI) (r2 = 0.633 and 0.652 respectively). It can be concluded that the interaction between HM and TS will greatly affect OMD IV and VDMI. Secondly OMD IV can be predicted by both iNDF IS and OMD GP with acceptable accuracy to allow for their use in future feed evaluations. [ABSTRACT FROM AUTHOR]

• Rice straw increases the stocking rate and bioeconomic efficiency. • Rice straw is a low-cost alternative for cow's nutrition in natural pastures. • Rice straw in the final third of gestation allows animal production maintenance. • Protein salt it is important for the use of rice straw for cows. • Residues from local crops are an alternative to intensify cow-calf systems. This study evaluated the effect of rice straw supplementation on cow-calf systems and the effect of increasing stocking rates on bio-economic efficiency. Three production systems were compared in which pregnant females were supplemented with different levels of rice straw in the prepartum: 1) 20 cows in 9 hectares (ha) of natural pasture without rice straw supplementation and stocking rate of 1,000 kg of body weight (BW)/ha (RSH0); 2) 30 cows in 13.5 ha of natural pasture receiving 5 kg of rice straw/animal/day and 1,000 kg BW/ha stocking (RSH5); and 3) 60 cows in 14 ha of natural pasture with 10 kg of rice straw/animal/day and stocking rate of 2,000 kg BW/ha (RSH10). The body condition score (BCS), cow weight at calving (CWC), and calf birth weight (CBW) were recorded on the first day and every 30 days. After calving, cows were moved to oat pasture (Avena strigosa) and ryegrass (Lolium multiflorum) with mineral supplementation where BW and BCS were evaluated every 30 days, and a transrectal ultrasound was performed every 15 days to determine the interval of parturition ovulation (IPO). Cows were separated in two groups and a fixed-time artificial insemination was performed (d130 and d165), followed 61 days of natural mating (d140-d175) and a gestation diagnosis 30 days after natural breeding (d231-d266) to verify the pregnancy rate (PR). Data comparison was performed by SPSS and productivity and gross margin (GM) were analyzed. We observed no difference in BCS between the beginning of prepartum until the parturition, nor in CWC, BW, IPO, and PR. The productivity and GM of RSH10 were 44.2 and 40.2% higher than RSH0 and 46.8 and 45% higher than RSH5, respectively. Thus, rice straw in the final third of gestation for cows in natural pasture allows the maintenance of cow's productive and reproductive parameters, as well as increased productivity while intensifying the system. [ABSTRACT FROM AUTHOR]

• Regardless of heading date time, of year significantly affects the digestibility of perennial ryegrass varieties. • As time of year progresses the intake and digestibility of tetraploid varieties increases over and above diploid varieties. • Perennial ryegrass varieties should be evaluated independently for dry matter intake and digestibility potential as variations in their chemical composition vary and significantly impact the traits in question. Two tetraploid varieties, Astonenergy and Delphin, and two diploid varieties of perennial ryegrass (Lolium perenne), Tyrella and Glenroyal, were evaluated for voluntary dry matter intake (VDMI) and in vivo organic matter digestibility (OMD) using Texel wether sheep housed in digestibility stalls. The structural profile and leaf, stem, dead proportions of the sward were also measured. The experiment was repeated on three occasions (Time Stage (TS)): May/June 2013 (TS1), August/September 2013 (TS2) and September/October 2014 (TS3). Data from both years were analysed separately. There was no variety effect on VDMI during TS1 (1481 ± 44.4 g/day), TS2 (1621 ± 41.7 g/day) or TS3 (1223 ± 86 g/day). There was a significant interaction between TS and variety for OMD (P <0.05) in 2013. OMD declined from TS1 to TS2 for all varieties (P <0.001). This was associated with an increased content of dead material in the sward in TS2 (P <0.001). There was a significant interaction (P <0.05) between TS and ploidy for VDMI as a percentage of bodyweight (VDMI % BW) and OMD in TS1 and TS2, as diploid varieties had higher values in TS1 and lower values than in TS2. In TS3, tetraploid varieties had higher VDMI (% BW) (P <0.05) and a tendency towards higher OMD (P =0.07) when compared to diploid varieties. These results indicate that there is a season by variety (and ploidy) interaction for VDMI and OMD. Future work should use an increased number of varieties to investigate the causes and timing of this interaction. [ABSTRACT FROM AUTHOR]

• Late lactation milk and milk solids yield is not affected by closing date in autumn. • Milk protein concentration decreases as silage replaces grazed grass in the diet. • 16 kg DM/ha increase in pre-grazing herbage mass for each extra one day closed. • Each 1 kg increase in herbage allowance results in +0.38 kg milk/cow in spring. The importance of increased grass availability in the diet of the early lactation dairy cow in spring-calving pasture-based systems is widely reported. To combat the effect of low over winter growth rates, closing swards earlier in autumn can allow for greater accumulation of herbage for grazing in spring. The aim of this study was to identify the impact of three autumn closing treatments (varying closing rotation dates); (1) Early – September 25th to November 9th, (2) Normal – October 10th to November 24th and (3) Late – October 25th to December 9th, on late lactation milk production and early lactation milk production in the subsequent spring. The goal was to identify the optimum recommendations for autumn closing management to achieve increased milk production in spring resulting from increased grass availability, without compromising on animal performance in late lactation. There was no effect of autumn closing treatment on late lactation milk yield or milk solids yield. There was, however, a decline in milk protein concentration, associated with the diet change at housing of the early closed treatment (−1.6 g/kg milk) and normal treatment (−0.7 g/kg milk) in autumn compared with the late closed treatment (41.5 g/kg milk), as a result of the increased silage fed during this period (473.2, 345.8 and 163.8 kg DM/cow, respectively). Each one day increase in closing resulted in an extra 16 kg DM/ha in pre-grazing herbage mass on February 1st of the subsequent year (R2 = =0.502). The resulting increases in pre-grazing herbage mass contributed to increased daily herbage allowance (DHA; +2.9 kg DM/cow) and total dry matter intake (+1.3 kg DM/cow) for the early treatment in spring compared with the normal and late closed treatment. Each 1 kg increase in DHA resulted in an increase of 0.38 kg milk/cow/day. A greater proportion of silage was required cumulatively on the early closed treatment (628 kg DM/cow) in contrast to the late closed treatment (419 kg DM/cow) between the autumn and spring period. However, the increased milk production associated with the increased grass availability in spring outweighed the cost associated with the increased silage requirement. Closing the farm early in autumn offers significant advantages in terms of higher DHA, increased dry matter intake and higher milk yields the following spring. Therefore, it is recommended the closing rotation should begin in late September and cease by mid-November, where there is a high demand for grass in early spring. [ABSTRACT FROM AUTHOR]