High milk production decreases cow-calf productivity within a highly available feed resource environment

The effects of including sprouted barley with alfalfa hay in the diet on ruminal health and performance of cow-calf pairs

The world population is growing exponentially, increasing demand to produce high-quality protein for human consumption. Changes in weather patterns, drought, and decreased land resources due to urbanization have increased the strain on the agriculture sector to meet world demands. An alternative method to combat these issues and continue to produce high-quality livestock feed would be through a controlled environment vertical farming system. Commonly, cereal grains, such as barley, are used in these systems to produce livestock feed. However, there is little information on the viability of feeding sprouted grains to beef cattle. Two diets of either feeder-quality alfalfa hay (n = 10 pairs; ALF) or the same alfalfa hay and sprouted barley (SB; 12.6% dry matter [DM]; n = 10 pairs) were fed for 90 d to Angus pairs with a steer calf during mid to late lactation. On days 0 and 90, body weight (BW), milk, rumen fluid, and body condition score were collected from cows and hip height and BW were recorded for calves. On day 10, BW was recorded for cows and calves and rumen fluid was collected from cows. Rumen fluid was also collected from cows on day 45. On day 55, BW was collected for both cows and calves and milk from cows. Intake was recorded throughout the trial via bunks with Vytelle technology. The PROC MIXED procedure of SAS was used to analyze all data with the day as a repeated measure to determine the main effect of diet. Individual volatile fatty acids (VFA) were measured as a percent of total VFA. No differences (P ≥ 0.16) were observed in calf BW, hip height, milk protein, fat, lactose, calf DM intake (DMI), or cow DMI. Cows fed SB tended (P = 0.08) to have a decreased somatic cell count compared to ALF. Percent butyrate was impacted by diet × day (P = 0.02), but no difference (P > 0.09) at any time points were detected. Additionally, a diet × day effect (P = 0.001) on rumen pH demonstrated that both groups stayed consistent until day 45 and then SB pH decreased the last 45 d. There was a day effect for total VFA (P = 0.0009), acetate:propionate (Ac:Pr; P < 0.0001), acetate (P < 0.0001), and propionate (P < 0.0001) demonstrating that total VFA, acetate, and Ac:Pr all increased throughout the trial, while propionate decreased. These results indicate that SB can be a potential alternative feed at this stage of production as it does not negatively impact health or production, but does affect the rumen pH and proportion of some VFA.

Effect of milking time on yield, composition, and antimicrobial components of milk in lactating goats

Various studies have attempted to improve the milk yield and composition in dairy animals. However, no study has examined the effects of milking at different times on milk yield and composition. Therefore, this study aimed to compare the yield, composition, and antimicrobial components of milk obtained from milking at different times in lactating goats. Eight goats were milked once daily at different times for three consecutive weeks (first week: 06:00 h; second week: 09:00 h; and third week: 12:00 h). The light ranged from 06:30 to 19:00 h. Milk and blood samples were collected once a day during milking time. Milking at 09:00 h resulted in a significantly higher milk yield than that obtained after milking at 06:00 and 12:00 h. Prolactin levels in plasma and the fat, Na+, β-defensin, and S100A7 (antimicrobial component) levels in milk were the lowest in the 09:00 h milking. These results indicate that milk yield, composition, and antimicrobial components can be affected by milking time, which may be related to the altered concentration of prolactin in the blood. These findings provide a rational basis for achieving maximal milk production with strong immunity by changing to a more effective milking time.

Beef embryos in dairy cows: calfhood growth of Angus-sired calves from Holstein, Jersey, and crossbred beef dams

Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. The objective of this sire-controlled study was to characterize the effects of beef or dairy maternal genetics and the dairy management system on calf growth. Pregnancies were created with a 2 × 2 factorial arrangement of dam breed (Holstein or Jersey) and mating type (artificial insemination or implantation of an in vitro produced embryo from a commercial beef cow oocyte). Resulting calves were reared in a calf ranch. Additionally, commercial beef cows were inseminated and reared resulting calves on range. Therefore, the five treatments were Angus × Holstein (A × H; n = 19), Angus × Jersey (A × J; n = 22), Angus × beef gestated by Holstein (H ET; n = 18), Angus × beef gestated by Jersey (J ET; n = 8), and Angus × beef raised by beef (A × B; n = 20). Beginning at birth, calf body weight, cannon circumference, forearm circumference, top width, hip width, and hip height were measured approximately every 28 d until ~196 d of age. At birth, A × J calves weighed the least (P < 0.01). At 150 d of age, body weight was greatest (P < 0.05) among A × B calves, intermediate among H ET and A × H calves, and least among J ET and A × J calves (P < 0.05). Morphometric differences were detected between treatments (multivariate analysis of variance, P < 0.01). Primary discriminant function scores identified A × B calves having lesser values than A × J or A × H calves (analysis of variance [ANOVA], P < 0.01); A × B calves had greater cannon circumference, greater top width, and less hip height (standardized loadings of -0.47, -0.48, and 0.63, respectively). Secondary discriminant function scores identified J ET and H ET to have greater forearm circumference-a key indicator of muscling-than A × J or A × H (ANOVA, P < 0.01; standardized loading of 0.99). The dairy management system limited growth rate of beef genetics compared to the beef management system. In addition, Holstein dams transmitted greater growth potential than Jersey dams. Replacing maternal dairy genetics with beef genetics moderated frame size and created a more muscular phenotype.

Beef embryos in dairy cows: feedlot performance, mechanistic responses, and carcass characteristics of straightbred Holstein calves and Angus-sired calves from Holstein, Jersey, or crossbred beef dams

Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. The objective of this sire-controlled study was to test the feedlot performance of straightbred beef calves raised on a calf ranch and to compare finishing growth performance, carcass characteristics, and mechanistic responses relative to beef × dairy crossbreds and straightbred beef cattle raised in a traditional beef cow/calf system. Tested treatment groups included straightbred beef steers and heifers reared on range (A × B; n = 14), straightbred beef steers and heifers born following embryo transfer to Holstein dams (H ET; n = 15) and Jersey dams (J ET; n = 16) The finishing trial began when cattle weighed 301 ± 32.0 kg and concluded after 195 ± 1.4 d. Individual intake was recorded from day 28 until shipment for slaughter. All cattle were weighed every 28 d; serum was collected from a subset of steers every 56 d. Cattle of straightbred beef genetics (A × B, H ET, and J ET) and A × H were similar in final shrunk body weight, dry matter intake, and carcass weight (P > 0.05 for each variable). Compared with A × J cattle, J ET was 42 d younger at slaughter with 42 kg more carcass weight (P < 0.05 for both variables). No difference was observed in longissimus muscle area between all treatments (P = 0.40). Fat thickness was greatest for straightbred beef cattle, least for A × J cattle, and intermediate for A × H cattle (P < 0.05). When adjusted for percentage of adjusted final body weight, feed efficiency was greater for straightbred beef cattle compared with beef × dairy crossbred cattle (P = 0.04). A treatment × day interaction was observed for circulating insulin-like growth factor I (IGF-I; P < 0.01); 112 d after being implanted, beef × dairy crossbred cattle had greater circulating IGF-I concentration than cattle of straightbred beef genetics (P < 0.05). Straightbred beef calves born to Jersey cows had more efficient feedlot and carcass performance than A × J crossbreds. Calves of straightbred beef genetics raised traditionally or in a calf ranch performed similarly in the feedlot.

A mathematical nutrition model adequately predicts beef and dairy cow intake and biological efficiency

The beef cow-calf sector accounts for 70% of feed consumed and greenhouse gases emitted for the beef industry, but there is no straightforward method to measure biological efficiency in grazing conditions. The objective of this study was to evaluate a mathematical nutrition model to estimate the feed intake and biological efficiency of mature beef cows. Data from dams (N = 160) and their second and third progeny (312 pairs) were collected from 1953 through 1980. Individual feed intake was measured at 28-d intervals year-round for dams and during 240-d lactation for progeny. Body weights of progeny were measured at 28-d intervals from birth to weaning, and of dams at parturition and weaning each production cycle. The milk yield of dams was measured at 14-d intervals. Dam metabolizable energy intake (DMEI) and milk energy yield (MEL) of each cow were predicted using the Cattle Value Discovery System beef cow (CVDSbc) model for each parity. Biological efficiency (Mcal/kg) was computed as the ratio of observed or predicted DMEI to observed calf weaning weight (PWW). Pearson correlation coefficients were computed using corr.test function and model evaluation was performed using the epiR function in R software. Average (SD) dam weight, PWW, DMEI, and observed MEL were 527 (86) kg, 291 (47) kg, 9584 (2701) Mcal/production cycle, and 1029 (529) Mcal, respectively. Observed and predicted DMEI (r = 0.93 and 0.91), and observed and predicted MEL (r = 0.58 and 0.59) were positively correlated for progeny 2 and 3, respectively. The CVDSbc model under-predicted DMEI (mean bias [MB] = 1,120 ± 76 Mcal, 11.7% of observed value) and MEL (MB = 30 ± 25 Mcal, 2.9% of observed value). Observed and predicted progeny feed intake were not correlated (r = 0.01, P-value = 0.79). Observed and predicted biological efficiency were positively correlated (r = 0.80 and 0.80, P-value ≤ 0.05) for parity 2 and 3, respectively, and the CVDSbc model under-predicted biological efficiency by 11% (MB = 3.59 ± 0.25 Mcal/kg). The CVDSbc provides reasonable predictions of feed intake and biological efficiency of mature beef cows, but further refinement of the relationship between calf feed intake and milk yield is recommended to improve predictions. Mathematical nutrition models can assist in the discovery of the biological efficiency of mature beef cows.

Frame Score, Grazing and Delayed Feedlot Entry Effect on Performance and Economics of Beef Steers from Small- and Large-Framed Cows in an Integrated Crop-Livestock System

When selling small-framed steers at weaning, profitability is diminished. The hypothesis is that by using a vertically integrated business model that includes retained ownership, extended grazing, abbreviated feedlot finishing, and selling at slaughter, profitability would increase. Crossbred yearling steers (n = 288) from small size Aberdeen Angus (Lowline) × Red Angus × Angus × Angus cows and moderate to large size Red Angus × Angus × Simmental × Gelbvieh cows calved May-June were randomly assigned (complete randomized design), in a 3 y study, to feedlot control (FLT) and extended grazing (GRZ) frame score treatment groups. Mean frame score for FLT were small frame (SF) 3.82 and large frame (LF) 5.63, and for GRZ, SF: 3.77 and LF: 5.53. Least-square means were utilized to identify levels of effects and to control family-wise error adjusted with Tukey test. The FLT control steers were housed in the feedlot and fed growing diets and subsequently high energy corn-based diets for 218 days. The GRZ steers grazed a sequence of forages (native range, field pea-barley mix, and unharvested corn) for 212 days and then were transferred to the feedlot and fed high energy corn-based finishing diets for 82 days. The SF GRZ steers grew more slowly grazing native range and annual forages compared to GRZ LF steers, but SF steer grazing cost per kg of gain was reduced 7.80%. Grazing steers did not grow to their full genetic potential. Slower growth during grazing allowed LF and SF steers to grow structurally before feedlot entry creating a compensatory feedlot finishing growth response. Overall, grazing steer performance exceeded steer performance of the FLT control treatment and LF grazing steers had the highest rate of gain, and lowest feed cost per kg of gain. The GRZ steer feedlot days on feed were reduced 136 days and total feed intake was reduced resulting in LF and SF grazing steer feed cost reductions of 175.9 and 165.3%, respectively. Extended grazing also resulted in LF and SF grazing steer hot carcass weights to be greater than control LF and SF steers and SF grazing steers had greater dressing percent, and marbling score. Carcass quality grade, meat tenderness, and cooking losses were similar. System net returns were highest for LF (USD 911.58), and SF (USD 866.61) grazing steers. Managerial modification combining retained ownership, extended grazing, and delayed feedlot entry increased profitability and eliminated market bias.

Assessment of milk yield and nursing calf feed intake equations in predicting calf feed intake and weaning weight among breeds

Nutrition models are important tools in management decisions, but improvements are needed for cow-calf producers to accurately predict nursing calf performance. Therefore, the objective of this study was to assess the ability of published milk yield (MY) and forage intake equations to predict calf feed intake and weaning weight (WW) using an independent, multi-breed dataset. A dataset with 406 nursing calves was used to evaluate two MY equations: 1) National Academies of Sciences, Engineering, and Medicine (2016) (NASEM) and 2) Wood (1967) (WOOD) and five feed intake equations: 1) equations from Table 9.1 in Tedeschi et al. (2006) (TED06), 2) equations 2 to 7 in Baker et al. (1976) (BAK76), 3) equation 25 in Tedeschi and Fox (2009) (TED09A), 4) equations 17, 19, and 24 in Tedeschi and Fox (2009) (TED09B), and 5) equation from Holloway et al. (1982) (HOL82). MY was measured at 14-d interval by hand milking, and individual feed intake of nursing calves was determined during a 240-d nursing period. Calf birth and WW were measured on days 0 and 240, respectively. Each combination of MY and feed intake equation was used to predict calf feed intake and WW from observed MY, calf birth weight, and calf slaughter weight. Predicted and observed values were compared using concordance correlation coefficient (CCC) and mean bias (MB). Factors affecting the deviation between observed and predicted values were analyzed using regression, and a revised equation was developed. Feed intake equations poorly predicted observed feed intake with CCC < 0.4 and MB ranged from -108% to 69%. However, statistics were slightly improved when using WOOD rather than the NASEM MY equation. BAK76 and TED09B feed intake equations were considerably more accurate (MB = -14.4% to 13.0%) in predicting feed intake but still not precise (CCC < 0.30). Predictions of WW had CCC ranging from 0.19 to 0.71 and MB ranging from -25.9% to 41.8% and were not significantly affected by the MY equation. TED06 and BAK76 feed intake equations were the most precise (CCC > 0.60) and accurate (MB = 1.7% to 8.5%) in predicting WW. Sire breed accounted for significant variation in the deviation between observed and predicted values of feed intake and in a revised equation to predict total feed energy intake from total milk energy intake. In conclusion, refinements of feed intake equations for nursing calves need to account for breed to improve current nutrition models.

Application of the California Net Energy System to grazed forage: feed values and requirements

The California Net Energy System (CNES) has been successfully used for many years to generate estimates of grazing animal energy requirements, supplemental needs, and energy value of grazed forage diets. Compared to pen feeding situations, validation of feed nutritive value estimates or animal performance projections are extremely difficult in grazing animals because many of the system inputs are constantly changing. A major difficulty in applying this or any energy accounting system in the field is acquiring accurate estimates of forage intake. We discuss the various equations available to estimate forage intake for grazing animals with emphasis on beef cows. Progress has been made in recent years although there remains substantial discrepancy among various equations, particularly in the upper range of forage digestibility. Validation work and further development is needed in this area. For lactating cows, our conclusion is that the adjustment of intake for milk production (0.2 kg increase in forage intake per kg of milk produced) needs to be increased to a minimum of 0.35. A particular challenge with the CNES for grazing beef cows is the dramatic interaction that can occur between genetic potential for production traits and nutrient availability. Examples from literature are provided and a case study is presented demonstrating that energy requirements are dynamic and depend on nutrients available in grazing systems. The CNES is a useful tool in grazing beef cattle management although there remains substantial opportunity and need to improve inputs and validate the system in grazing situations.

Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.

The effect of cow udder score on cow/calf performance in the Nebraska Sandhills

Poor udder and teat confirmation decreases profitability due to decreased calf weaning weight, increased incidence of mastitis and labor, and decreased cow lifetime productivity. Therefore, the objective of this retrospective study was to evaluate the effect of beef cow udder score on cow performance and pre- and postweaning progeny performance. In a 5-yr study, crossbred cows at the Gudmundsen Sandhills Laboratory, Whitman, NE, were assigned an udder score each year at calving, from 1 to 5, using an udder and teat combination score. Cows were grouped by udder scores and classified as either low udder score (LUS, udder score 1 or 2; n = 223) or high udder score (HUS, udder score 3 or 4; n = 1,742). The udder score combines udder conformation and a teat scoring system. Low udder scores consisted of pendulous udders and large teats, whereas HUS consisted of tight udders and small, symmetrical teats. Mixed models were used to evaluate udder score on cow performance and calf pre- and postweaning performance. Cow body weight (BW) at prebreeding and weaning was greater (P < 0.01) in LUS cows compared with HUS counterparts. Pregnancy rate was not different (P = 0.35) between udder classification groups. Calf BW at birth (P = 0.95), weaning (P = 0.40), and adjusted 205-d BW (P = 0.28) were not different between udder groups. Cow udder score did not influence feedlot entry (P = 0.41) and final BW (P = 0.30), dry matter intake (P = 0.53), average daily gain (P = 0.60), and gain:feed ratio (P = 0.85) of steer progeny. However, steers from HUS dams had greater hot carcass weight (HCW; P = 0.04) and backfat thickness (P = 0.02) compared with LUS counterparts. Results from this study suggest cows with less desirable udder structure may not have a negative impact on calf preweaning growth and performance; however, backfat thickness and HCW in the finishing phase were lower in steers from cows with a lower udder score.

BEEF SPECIES-RUMINANT NUTRITION CACTUS BEEF SYMPOSIUM: Sustainable and economically viable management options for cow/calf production through enhanced beef cow metabolic efficiency1

Beef cow herds are expected to be metabolically and reproductively efficient in varied and ever changing environmental conditions. Therefore, selection and management of grazing beef cows provides unique and diverse challenges in achieving optimal production efficiency for any environment. Beef cows face dynamic and highly variable nutritional environments that periodically are inadequate in meeting nutrient and energy requirements. Nutritional management during high metabolically stressed and key physiological states can lead to increased or decreased metabolic efficiency. Conversely, cow metabolic efficiency may be reduced in many production systems due to surplus nutritional inputs and reduced exposure to environmental stressors. Alternatively, metabolically potent supplementation strategies targeting enhanced energy metabolism and endocrine mechanisms would increase beef cow metabolic and economic efficiency. Metabolic efficient beef cows adapt to environmental changes by adjusting their metabolic energy utilization in order to match current environmental conditions and remain reproductively competent. This mechanism involves adaptive processes that drive adjustments in nutrient partitioning and energy utilization efficiency. However, the variation in metabolic and reproductive efficiency among beef cows within cow/calf production systems is substantial, suggesting a lack of complete integration of nutrition, genetics, and reproduction with environmental constraints and conditions. Better integration and understanding of the interactions may lead to advancements in metabolic efficiency of the cowherd. Metabolic flexibility is recognized as an important trait in dairy production but has received little attention thus far in beef cattle. Overall, management and supplementation strategies in cow/calf systems from a mechanistic, targeted nutritional approach during key physiological periods would hasten improvements in metabolic efficiency.

Post-weaning feed efficiency decreased in progeny of higher milk yielding beef cows

Current trends in the beef industry focus on selecting production traits with the purpose of maximizing calf weaning weight; however, such traits may ultimately decrease overall post-weaning productivity. Therefore, the objective of this study was to evaluate the effects of actual milk yield in mature beef cows on their offspring's dry matter intake (DMI), BW, average daily gain, feed conversion ratio (FCR) and residual feed intake (RFI) during a ~75-day backgrounding feeding trial. A period of 24-h milk production was measured with a modified weigh-suckle-weigh technique using a milking machine. After milking, cows were retrospectively classified as one of three milk yield groups: Lower (6.57±1.21 kg), Moderate (9.02±0.60 kg) or Higher (11.97±1.46 kg). Calves from Moderate and Higher milk yielding dams had greater (P<0.01) BW from day 0 until day 75 at the end of the backgrounding feeding phase; however, day 75 BW were not different (P=0.36) between Lower and Moderate calves. Body weight gain was greater (P=0.05) for Lower and Moderate calves from the day 0 BW to day 35 BW compared with Higher calves. Overall DMI was lower (P=0.03) in offspring from Lower and Moderate cows compared with their Higher milking counterparts. With the decreased DMI, FCR was lower (P=0.03) from day 0 to day 35 in calves from Lower and Moderate milk yielding dams. In addition, overall FCR was lower (P=0.02) in calves from Lower and Moderate milk yielding dams compared with calves from Higher milk yielding dams. However, calving of Lower milk yielding dams had an increased (P=0.04) efficiency from a negative RFI value compared with calves from Moderate and Higher milking dams. Results from this study suggest that increased milk production in beef cows decreases feed efficiency during a 75-day post-weaning, backgrounding period of progeny.