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Fourteen organic dairy farms in the northeastern United States were used to evaluate (1) seasonal variation in bioactive milk fatty acid (FA) profile from 2012 to 2015 and (2) supplementation of ground whole flaxseed (GFLX) to maintain elevated concentrations of bioactive milk FA during the nongrazing season. During regular farm visits, milk, feed, and pasture samples were collected, and diet composition, milk yield, and milk composition were recorded. During winters of 2013 to 2014 and 2014 to 2015, 9 farms supplemented GFLX at 6% of diet DM to half of each herd (n = 238 cows per treatment). Milk samples were collected and pooled by treatment (GFLX or control). Data were analyzed using the MIXED procedure of SAS. A significant month × year interaction (P 0.15) milk yield or concentrations of milk fat or protein; however, BCS tended (P = 0.08) to be greater for GFLX cows. Compared with the control diet, GFLX decreased (P

A 4-unit, dual-flow continuous culture fermentor system was used to assess nutrient digestibility, volatile fatty acids (VFA) production, bacterial protein synthesis, and methane (CH4) output of warm-season annual grasses. Treatments were randomly assigned to fermentors in a 4 × 4 Latin square design using 7 d for adaptation to treatment and 3 d for sample collection. Treatments were (1) 100% orchardgrass (Dactylis glomerata L.; ORD); (2) 50% orchardgrass + 50% Japanese millet [Echinochloa esculenta (A. Braun) H. Scholz; MIL]; (3) 50% orchardgrass + 50% brown midrib sorghum × sudangrass (Sorghum bicolor L. Moench × S. bicolor var. sudanense; SSG]; or (4) 50% orchardgrass + 25% millet + 25% sorghum × sudangrass (MIX). Fermentors were fed 60 g of dry matter (DM)/d in equal portions of herbage 4 times daily (0730, 1030, 1400, and 1900 h). To replicate a typical 12-h pasture rotation, fermentors were fed the orchardgrass at 0730 and 1030 h and the individual treatment herbage (orchardgrass, Japanese millet, sorghum × sudangrass, or 50:50 Japanese millet and sorghum × sudangrass) at 1400 and 1900 h. Gas samples for CH4 analysis were collected 6 times daily at 0725, 0900, 1000, 1355, 1530, and 1630 h. Fermentor pH was determined at the time of feeding, and fermentor effluent samples for NH3-N and VFA analyses were taken daily at 1030 h on d 8, 9, and 10. Samples were also analyzed for DM, organic matter (OM), crude protein, and fiber fractions to determine nutrient digestibilities. Bacterial efficiency was estimated by dividing bacterial N by truly digested OM. True DM and OM digestibilities and pH were not different among treatments. Apparent OM digestibility was greater in ORD than in MIL and SSG. The concentration of propionate was greater in ORD than in SSG and MIX, and that of butyrate was greatest in ORD and MIL. Methane output was greatest in MIL, intermediate in ORD, and lowest in SSG and MIX. Nitrogen intake did not differ across treatments, whereas bacterial N efficiency per kilogram of truly digestible OM was greatest in MIL, intermediate in SSG and MIX, and lowest in ORD. True crude protein digestibility was greater in ORD versus MIL, and ORD had lower total N, non-NH3-N, bacterial N, and dietary N in effluent flows than MIL. Overall, we detected little difference in true nutrient digestibility; however, SSG and MIX provided the lowest acetate to propionate ratio and lower CH4 output than MIL and ORD. Thus, improved warm-season annual pastures (i.e., brown midrib sorghum × sudangrass) could provide a reasonable alternative to orchardgrass pastures during the summer months when such perennial cool-season grass species have greatly reduced productivity.

Pasture samples (n = 380) collected during the grazing season on 14 dairy farms (2012 to 2014) were analyzed for nutritional composition. The MIXED procedure of SAS was used to test effect of year, month, and farm. Frequency analysis was used to determine the proportion of pasture samples that met minimum NEl, CP, and macro mineral requirements of lactating Holstein and Jersey cows (25 kg of milk/d; NRC, 2001). The Large Ruminant Nutrition System model was used to evaluate feeding strategies that accompanied grazing. Each year, forage quality declined with the advancing grazing season (CP, NEl, P

Dairy farms that grow more perennial vegetation as grazing pastures or conserved forages can offer many environmental benefits but may show reduced milk production relative to farms feeding higher amounts of grain and corn silage. Because yields of annual and perennial crops vary with soil type, an accurate comparison of the productive potential of these systems over county or regional scales may require taking into account spatial variation in soil quality. In this study, we present a novel approach to calculate the production from dairy systems that adjusts average crop yields to the productive potential of local soils using the National Commodity Crop Productivity Index (NCCPI). We used on-farm survey data to define confinement and grazing systems with varying amounts of perennial forage and applied our method to a sample of five counties in the northeast United States. High corn silage farm systems produced 21 to 168% more milk per hectare of farmland than grazing-based farm systems, but variation among counties was greater than variation among systems, with the best (Lancaster, PA) producing as much as 5.3 times more than the least (Orange, VT). Adjusting yields for soil productivity had smaller effects on milk production than differences in farm system or county. On average, grazing farm systems generally produced slightly more milk when yields were adjusted using the NCCPI (8%) while high corn silage systems showed a moderate decrease (13%). Compared to scenarios of all local crop production, scenarios with unlimited corn and soybean imports often more than doubled county-scale milk production. Restricting grain imports to prevent excess phosphorus resulted in a 3–15% decrease in milk production relative to unlimited imports, but still produced far more milk than in the all local production scenarios. Sensitivity analysis of the model showed that milk production in each county was very responsive to changes in perennial forage yields (especially for grazing systems), responsive to changes in average daily milk production per cow, and generally not responsive to changes in the productive lifetime of lactating cows. This study demonstrates a persistent tradeoff between perenniality and production in dairy systems, but suggests that opportunities may exist to maintain current milk production levels in the Northeast while also expanding land cover in perennial vegetation.

A 4-unit dual-flow continuous-culture fermentor system was used to assess the effect of supplementing 7-d sprouted barley (SB) or barley grain (BG) with an herbage-based or haylage-based diet on nutrient digestibility, volatile fatty acid (VFA) profiles, bacterial protein synthesis, and methane (CH 4 ) output. Treatments were randomly assigned to fermentors in a 4×4 Latin square design with a 2×2 factorial arrangement using 7 d for diet adaptation and 3 d for sample collection. Experimental diets were (1) 55.5g of herbage dry matter (DM) + 4.5g of SB DM, (2) 56.0g of herbage DM + 4.0g of BG DM, (3) 55.5g of haylage DM + 4.5g of SB DM, and (4) 56.0g of haylage DM + 4.0g of BG DM. Forages were fed at 0730, 1030, 1400, and 1900h, whereas SB and BG were fed at 0730 and 1400h. Gas samples for CH 4 analysis were collected at 0725, 0900, 1000, 1355, 1530, and 1630h on d 8, 9, and 10. Fluid samples were taken once daily on d 8, 9, and 10 for pH measurements and for ammonia-N and VFA analysis and analyzed for DM, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber for determination of nutrient digestibilities and estimation of bacterial protein synthesis. Orthogonal contrasts were used to compare the effect of forage source (haylage vs. herbage), supplement (BG vs. SB), and the forage × supplement interaction. Apparent and true DM and organic matter digestibilities as well as apparent crude protein digestibility were not affected by forage source. However, true DM digestibility was greatest for diets supplemented with SB. Apparent neutral and acid detergent fiber digestibilities of herbage-based diets were higher than haylage-based diets but fiber digestibility was not affected by supplement. Diets supplemented with SB had higher mean and minimum pH than BG; however, maximum pH was not affected by diet. Supplementation with BG produced a greater concentration of total VFA compared with diets supplemented with SB. Haylage-based diets produced greater CH 4 output compared with herbage-based diets but supplementation did not affect CH 4 output. Efficiency of bacterial protein synthesis was greater for herbage-based diets compared with haylage-based diets, with no effect of supplementation. Overall, supplementation with SB marginally increased true DM digestibility of herbage- and haylage-based diets but did not affect fiber and crude protein digestibilities, CH 4 output, and bacterial efficiency, compared with BG.

Proponents of ultra-high stocking density (UHSD) grazing emphasize increased forage-use efficiency and soil improvement by grazing mature forage with stocking densities up to 560,425 kg/ha of beef cattle on small paddocks with rest periods up to 125 d. However, it is unclear whether this management technique is appropriate for dairy farms in the northeastern United States. A case study was conducted to characterize management practices and forage and soil quality on dairy farms using self-described UHSD grazing. Data collected on 4 organic dairy farms in Pennsylvania and New York practicing UHSD grazing included pasture and soil nutrient analyses, stocking density, botanical composition, and pasture stratification. Herds were mixed breed with milk yields ranging from 11.9 to 17.7 kg/d per cow. Stocking density ranged from 49,421 to 377,912 kg/ha with 30 to 49 d of forage rest. Forage consumed was 46 and 45% of total available in 2012 and 2013, respectively. Within the available forage that was eaten, cows consumed 75% of forage from layers 33 cm and higher and 49% from below 33 cm. Across years, forage CP, NDF, and NE l averaged 24%, 44.7%, and 1.43 Mcal/kg, respectively. The increase in forage quality during 2012 was likely a result of forage being less mature at each successive grazing. Soil mineral content and pH were within recommended levels. Grazing dairies in Pennsylvania and New York have taken a modified approach to UHSD grazing by using forages more mature than recommended in management-intensive grazing systems by allowing longer periods of forage rest.

In 2010, the National Organic Program implemented a rule for the US stating that pasture must be a significant source of feed in organic ruminant systems. This article will focus on how the pasture rule has impacted the management, economics and nutritional value of products derived from organic ruminant systems and the interactions of grazing cattle with pasture forages and soils. The use of synthetic fertilizers is prohibited in organic systems; therefore, producers must rely on animal manures, compost and cover crops to increase and maintain soil nitrogen content. Rotational and strip grazing are two of the most common grazing management practices utilized in grazing ruminant production systems; however, these practices are not exclusive to organic livestock producers. For dairy cattle, grazing reduces foot and leg problems common in confinement systems, but lowers milk production and exposes cows to parasites that can be difficult to treat without pharmaceuticals. Organic beef cattle may still be finished in feedlots for no more than 120 days in the US, but without growth hormones and antibiotics, gains may be reduced and illnesses increased. Grazing reduces the use of environmentally and economically costly concentrate feeds and recycles nutrients back to the soil efficiently, but lowers the rate of beef liveweight gain. Increased use of pasture can be economically, environmentally and socially sustainable if forage use efficiency is high and US consumers continue to pay a premium for organic beef and dairy products.

The objective of this study was to evaluate the use of fecal near-infrared reflectance spectroscopy (NIRS) profiling to predict diet nutritional characteristics and voluntary DMI in beef cattle. Fecal samples were collected for growing cattle across 11 experiments in which individual animal performance and DMI was measured. Dried and ground fecal composite samples collected from each animal were subjected to fecal NIRS analysis by a Foss NIRS 6500 scanning monochromator (Foss, Eden Prairie, MN) at the Grazingland Animal Nutrition Laboratory (Temple, TX). Fecal spectra were then used to develop equations to predict diet composition (trials 1 to 11; = 408), digestibility (trials 1 to 5; = 155), and DMI (trials 1 to 11; = 408). Coefficients of determination for calibration () and cross-validation () for prediction of diet nutritional characteristics were lower for NDF ( = 0.85; = 0.82) than for CP ( = 0.90; = 0.88). For the prediction of DMI, and ranged from 0.69 and 0.67 for the prediction of trial-average DMI to 0.76 and 0.73 for the prediction of fecal-collection-period DMI. While the and obtained for the prediction of DMI were lower than those obtained for the prediction of diet composition or digestibility, fecal NIRS prediction equations for DMI were successful in predicting the mean DMI of groups, as no differences were found for the prediction of fecal-collection-period DMI (Diff. = 1.10; = 0.72) or trial DMI (Diff. = -0.47; = 0.86).

A meta-analysis was conducted to examine phenotypic relationships between feed efficiency, scrotal circumference, and semen quality traits in yearling bulls. Data evaluated were obtained from 5 postweaning trials involving Angus (n = 92), Bonsmara (n = 62), and Santa Gertrudis (n = 50) bulls fed diets that ranged from 1.70 to 2.85 Mcal ME/kg DM. After an adaptation period of 24 to 28 d, feed intake was measured daily, and BW was measured at 7- or 14-d intervals during the 70- to 77-d trials. Ultrasound carcass traits (12th-rib back fat thickness, BF; LM area, LMA) and scrotal circumference (SC) were measured at the start and end of each trial. Semen samples were collected by electroejaculation within 51 d of the end of the trials when the age of bulls averaged from 365 to 444 d and were evaluated for progressive sperm motility and morphology. Residual feed intake (RFI) was calculated as the difference between actual DMI and expected DMI from linear regression of DMI on ADG and midtest BW(0.75), with trial, trial by ADG, and trial by midtest BW(0.75) as random effects. Across all studies, bulls with low RFI phenotypes (0.5 SD below the mean RFI of 0) consumed 20% less DM and had 10% less BF but had similar ADG, SC, and semen quality traits compared with high-RFI bulls (0.5 SD above the mean RFI of 0). Gain to feed ratio was strongly correlated with ADG (0.60) and weakly correlated with initial BW (-0.17) and DMI (-0.26). Residual feed intake was not correlated with ADG, initial age, or BW but was correlated with DMI (0.71), G:F (-0.70), and BF (0.20). Initial SC (-0.20), gain in SC (-0.28), and percent normal sperm (-0.17) were correlated with G:F, but only sperm morphology was found to be weakly associated with RFI (0.13). These data suggest that RFI is not phenotypically associated with SC or sperm motility but is weakly associated with sperm morphology.

Willow Creek' forage winter wheat (Triticum aestivum L.) (Reg. No. CV-1032, PI 655073) was released by the Montana Agricultural Experiment Station. Awnletted cereal forages are widely used for hay production on integrated crop- livestock operations in the Northern Great Plains. Five awnletted winter wheat accessions were evaluated for forage characteristics in 1996 and 1997, and Willow Creek was selected directly from PI 306505. Willow Creek was evaluated in replicated trials for forage yield and quality, grain yield, and agronomic characteristics from 1998 through 2008. Willow Creek is an awnletted winter wheat cultivar with good performance as an annual hay crop under irrigated or rainfed conditions in Montana and Wyoming. This cultivar has excellent winterhardiness and is tall and late-maturing. Willow Creek has good forage quality characteristics suitable for use by livestock in winter maintenance diets.

A 4-unit dual-flow continuous culture fermentor system was used to assess the effects of supplementing orchardgrass (Dactylis glomerata L.) with 2 levels [5 and 10% of total dry matter (DM) fed] of starchy (barley grain, BAR) or fibrous (beet pulp, BP) carbohydrate sources on nutrient digestibility, volatile fatty acid (VFA) production, bacterial protein synthesis, and CH4 output. Treatments were randomly assigned to fermentors in a 4×4 Latin square design with a 2×2 factorial arrangement using 7 d for microbial adaptation and 3 d for sample collection. Treatments included (1) 57g of DM orchardgrass + 3g of DM BAR, (2) 54g of DM orchardgrass + 6g of DM BAR, (3) 57g of DM orchardgrass + 3g of DM BP, or (4) 54g of DM orchardgrass + 6g of DM BP. Feedings occurred at 0900, 1030, 1400, and 1900h throughout four 10-d periods. Gas samples for CH4 analysis were collected 6 times daily at 0725, 0900, 1000, 1355, 1530, and 1630h. Fermentor samples for pH, NH3-N, and VFA analysis were taken on d 8, 9, and 10. Samples were also analyzed for DM, organic matter, crude protein, purines, neutral detergent fiber, and acid detergent fiber to determine nutrient digestibilities and estimation of bacterial protein synthesis. Apparent and true DM and organic matter digestibilities were not affected by supplement source. Apparent neutral and acid detergent fiber digestibilities were greater for BAR than BP. Conversely, apparent crude protein digestibility was greater for BP than BAR. Mean and maximum pH tended to be greatest for BAR than BP. Minimum pH was greater at the lower level (5% of diet DM) of supplementation. Barley produced greater concentrations of total VFA and acetate, whereas BP had greater daily outputs of CH4. Significant supplement type × level interactions were found for bacterial N flow and efficiency. Overall, supplementing orchardgrass with BP improved crude protein digestibility, reduced fiber digestibility and total VFA concentration, but increased CH4 output compared with BAR.

The objectives of this study were to determine if residual feed intake (RFI) classification of beef heifers affected efficiency of forage utilization, body composition, feeding behavior, heart rate, and physical activity of pregnant females. Residual feed intake was measured in growing Bonsmara heifers for 2 yr (n=62 and 53/yr), and heifers with the lowest (n=12/yr) and highest (n=12/yr) RFI were retained for breeding. Of the 48 heifers identified as having divergent RFI, 19 second-parity and 23 first-parity females were used in the subsequent pregnant-female trial. Pregnant females were fed a chopped hay diet (ME=2.11 Mcal kg(-1) DM) in separate pens equipped with GrowSafe bunks to measure individual intake and feeding behavior. Body weights were measured at 7-d intervals and BCS and ultrasound measurements of 12th-rib fat depth, rump fat depth, and LM area obtained on d 0 and 77. Heart rate and physical activity were measured for 7 consecutive d. First-parity females had lower (P

Residual feed intake (RFI) quantifies inter-animal variances in dry matter intake (DMI) independent of variation in body size and productivity (e.g. growth, milk). In beef cattle, Herd and Arthur (2009) estimated that approximately one-third of the biological variation in RFI was due to inter-animal differences in digestion, heat increment, body composition, and activity, with the remaining variation associated with energy expenditure of metabolic processes. Given that RFI is independent of BW and level of production, it is an ideal trait for discovery of genomic regions (Rolf et al., 2011) and functional genes (Chen et al., 2011) associated with efficiency of feed utilization. Some variation in RFI may be caused by individual differences in immune system function. The immune system is an energetically expensive system. A previous study showed that metabolic heat production and oxygen consumption increased 20-30% in mice that were immunized with a relatively benign antigen (Demas et al., 1997). The objective of this work was to examine whether the genes associated with the immune system were differentially expressed by beef cattle with divergent RFI phenotypes.