Effect of mature body weight and stocking rate on cow and calf performance, cow herd efficiency, and economics in the southeastern United States

Importance of Foot and Leg Structure for Beef Cattle in Forage-Based Production Systems

Understanding the relationship of foot angle and claw set to beef cattle structural soundness will be critical to the selection of animals that fit forage-based production systems. In an effort to address concerns about foot and leg structure, the American Angus Association's foot angle and foot claw set expected progeny differences (EPD) were developed in 2019. As a result, these relatively new EPD and associated guidelines have limited phenotypic data submitted thus far. While ample research has evaluated lameness and foot issues in the dairy breeds, less is known about the factors that affect foot structure in beef cattle. This review focuses on beef cattle foot and leg structure, selection factors that may have led to increased problems with feet and legs, and the importance of foot and leg structure in forage-based grazing production systems. Specifically, the importance of locomotion and freedom of movement in extensive rangeland environments is discussed relative to the current literature. In addition, environmental factors that may influence foot and leg structure are addressed as well as heritability of various aspects of foot and leg traits. Where possible, information gaps and research needs are identified to enhance further investigation and the improvement of foot and leg selection tools.

Breed and heterotic effects for mature weight in beef cattle

Cow mature weight (MWT) is heritable and affects the costs and efficiency of a breeding operation. Cow weight is also influenced by the environment, and the relationship between the size and profitability of a cow varies depending on production system. Producers, therefore, need tools to incorporate MWT in their selection of cattle breeds and herd replacements. The objective of this study was to estimate breed and heterotic effects for MWT using weight-age data on crossbred cows. Cow's MWT at 6 yr was predicted from the estimated parameter values-asymptotic weight and maturation constant (k)-from the fit of the Brody function to their individual data. Values were obtained for 5,156 crossbred cows from the U.S. Meat Animal Research Center (USMARC) Germplasm Evaluation Program using 108,957 weight records collected from approximately weaning up to 6 yr of age. The cows were produced from crosses among 18 beef breeds. A bivariate animal model was fitted to the MWT and k obtained for each cow. The fixed effects were birth year-season contemporary group and covariates of direct and maternal breed fractions, direct and maternal heterosis, and age at final weighing. The random effects were direct additive and residual. A maternal additive random effect was also fitted for k. In a separate analysis from that used to estimate breed effects and (co)variances, cow MWT was regressed on sire yearling weight (YWT) Expected Progeny Differences by its addition as a covariate to the animal model fitted for MWT. That regression coefficient was then used to adjust breed solutions for sire selection in the USMARC herd. Direct heterosis was 15.3 ± 2.6 kg for MWT and 0.000118 ± 0.000029 d-1 for k. Maternal heterosis was -5.7 ± 3.0 kg for MWT and 0.000130 ± 0.000035 d-1 for k. Direct additive heritabilities were 0.56 ± 0.03 for MWT and 0.23 ± 0.03 for k. The maternal additive heritability for k was 0.11 ± 0.02. The direct additive correlation between MWT and k was negligible (0.08 ± 0.09). Adjusted for sire sampling, Angus was heaviest at maturity of the breeds compared. Deviations from Angus ranged from -8.9 kg (Charolais) to -136.7 kg (Braunvieh). Ordered by decreasing MWT, the breeds ranked Angus, Charolais, Hereford, Brahman, Salers, Santa Gertrudis, Simmental, Maine Anjou, Limousin, Red Angus, Brangus, Chiangus, Shorthorn, Gelbvieh, Beefmaster, and Braunvieh. These breed effects for MWT can inform breeding programs where cow size is considered a key component of the overall profitability.

Cow efficiency: modeling the biological and economic output of a Michigan beef herd

In recent decades, beef cattle producers have selected cattle for biological traits (i.e., improved growth) to maximize revenue, leading to an increase in average cow body size. However, matching cow size to the production environment would allow producers to maximize productivity and economic returns per unit of land. This may help meet the goals of sustainable intensification, but environmental complexity and varying cow-calf production systems dictates a regional approach. The objective of this experiment was to examine the biological efficiency and economic returns of a Northern Michigan cow-calf system. We hypothesized that biological efficiency and economic returns would decrease with increasing cow body size. Data were collected from a Red Angus cow herd located at the Lake City AgBio Research Center in Lake City, MI from 2011 to 2018 on cow age, weight, and body condition score at weaning, and subsequent 205 d adjusted calf weaning weight (WW), sex, and yearling weight. Biological efficiency was defined as WW as a percentage of cow body weight (DBW). Enterprise budgeting techniques were used to calculate expected net returns from 2011 to 2018 after classifying cows into 11 BW tiers at 22.67 kg intervals beginning at 430.83 kg. Forward-looking net present value (NPV) was calculated using the same tier system, for a 10-yr production cycle with the baseline being a 200 d grazing season. Weaning weight increased with increasing DBW (P < 0.01), but the percentage of cow body weight weaned was reduced by −38.58 × Ln(DBW) (P < 0.01). This led to cows weaning 26.38 kg/ha more with every 100 kg drop in DBW. Expected net returns from 2011 to 2018 did not differ by DBW tier on a per cow basis but did on a per ha basis with a decrease in $10.27/ha with each increase in DBW tier (P < 0.01). Net present value was maximized in the baseline scenario at 453.51 kg DBW and decreased in value as DBW increased. These results suggest that for a Northern Midwestern cow-calf herd, comparatively lighter cows provide a higher economic value on a land basis.

The impact of cow size on cow-calf and postweaning progeny performance in the Nebraska Sandhills

Optimizing beef production system efficiency requires an understanding of genetic potential suitable for a given production environment. Therefore, the objective of this retrospective analysis was to determine the influence of cow body weight (BW) adjusted to a common body condition score (BCS) of 5 at weaning-influenced cow-calf performance and postweaning steer and heifer progeny performance. Data were collected at the Gudmundsen Sandhills Laboratory, Whitman, NE, on crossbred, mature cows (n = 1,607) from 2005 to 2017. Cow BCS at calving, prebreeding, and weaning were positively associated (P < 0.01) with greater cow BW. Increasing cow BW was positively associated (P < 0.01) with the percentage of cows that conceived during a 45-d breeding season. For every additional 100-kg increase in cow BW, calf BW increased (P < 0.01) at birth by 2.70 kg and adjusted 205-d weaning BW by 14.76 kg. Calf preweaning average daily gain (ADG) increased (P < 0.01) 0.06 kg/d for every additional 100-kg increase in cow BW. Heifer progeny BW increased (P < 0.01) postweaning with every additional 100-kg increase in dam BW. Dam BW did not influence (P ≥ 0.11) heifer puberty status prior to breeding, overall pregnancy rates, or the percentage of heifers calving in the first 21 d of the calving season. Steer initial feedlot BW increased by 7.20 kg, reimplant BW increased by 10.47 kg, and final BW increased by 10.29 kg (P ≤ 0.01) for every additional 100-kg increase in dam BW. However, steer feedlot ADG was not influenced (P > 0.67) by dam BW. Hot carcass weights of steers were increased (P = 0.01) by 6.48 kg with every additional 100-kg increase in cow BW. In a hypothetical model using the regression coefficients from this study, regardless of pricing method, cow-calf producers maximize the highest amount of profit by selecting smaller cows. Overall, larger-sized cows within this herd and production system of the current study had increased reproductive performance and offspring BW; however, total production output and economic returns would be potentially greater when utilizing smaller-sized cows.

Comparison of different functions to describe growth from weaning to maturity in crossbred beef cattle1

Cow mature weight (MWT) has increased in the past 30 yr. Larger cows cost more to maintain, but their efficiency-and thus profitability-depends on the production environment. Incorporating MWT effectively into selection and mating decisions requires understanding of growth to maturity. The objective of this study was to describe growth to maturity in crossbred beef cattle using Brody, spline, and quadratic functions. Parameter estimates utilized data on crossbred cows from cycle VII and continuous sampling phases of the Germplasm Evaluation Program at the U.S. Meat Animal Research Center. The MWT were estimated at 6 yr from the fitted parameters obtained from the Brody (BMWT), spline (SMWT), and quadratic (QMWT) functions. These were defined as BMWT, SMWT, and QMWT for the Brody, spline, and quadratic functions, respectively. Key parameters from the Brody function were BMWT and maturing constant. The spline was fitted as piecewise linear where the two linear functions joined at a knot. Key parameters were knot position and SMWT. For the quadratic model, the main parameter considered was QMWT. Data were scaled for fitting such that 180 d was the y-intercept with the average weight at 180 d (214.3 kg) subtracted from all weights. Weights were re-expressed by adding 214.3 kg after analysis. Once data were edited, with outliers removed, there were parameter estimates for 5,156, 5,041, and 4,905 cows for the Brody, spline, and quadratic functions, respectively. The average maturing constant (SD) was 0.0023 d-1 (0.0008 d-1). The mean MWT estimates (SD) from the Brody, spline, and quadratic functions were 650.0 kg (64.0 kg), 707.3 kg (79.8 kg), and 597.8 kg (116.7 kg), respectively. The spline function had the highest average R2 value when fit to individual cows' data. However, the Brody function produced more consistent MWT estimates regardless of the timeframe of data available and produced the fewest extreme MWT. For the spline and quadratic functions, weights through 4 and 5 yr of age, respectively, were needed before consistent estimates of MWT were obtained. Of the three functions fitted, the Brody was best suited for estimating MWT at a later age in crossbred beef cattle.

Effects of stocking rate, forage management, and grazing management on performance and economics of cow-calf production in Southwest Arkansas

The objective this research was to determine the effect of application of multiple grazing management practices at 2 stocking rates (SR) on the productivity and economics of the cow-calf enterprise in the Southeastern United States over a 4-yr period. Pasture management systems included: continuous grazing management at a moderate SR (0.8 ha/cow; CG) without additional forage management, rotational grazing management at a moderate SR (0.8 ha/cow (MR) with addition of stockpiled bermudagrass [ (L.) Pers.] and complementary cool season annuals, and rotational grazing management similar to MR but with a high SR (0.4 ha/cow; HR). Stockpiling in MR and HR was managed by fertilization of 0.2 ha/cow of bermudagrass in early August with 168 kg ammonium nitrate and deferring grazing until November. Wheat (; 112 kg/ha) and annual ryegrass ( Lam.; 28 kg/ha) were interseeded (0.2 ha/cow) in HR and MR with a no-till drill in the fall. Cow and calf performance and economics data were analyzed by ANOVA using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) and pregnancy percentage was analyzed using the GLIMMIX procedure of SAS; pasture was the experimental unit and year was the random block. Hay feeding days decreased ( < 0.01) from 107 ± 10.9 d for CG to 37 ± 10.9 d for HR, which was further reduced ( = 0.01) to 15 ± 10.9 d for MR. Pregnancy percentage did not differ ( = 0.20) among treatments. Weaning BW in CG (237 ± 7.3 kg) tended ( = 0.09) to be greater than in MR (227 ± 7.3 kg) and were greater ( < 0.01) than in HR (219 ± 7.3 kg). However, total weaning BW per hectare was 89% greater ( < 0.01) for HR compared with CG and MR, which did not differ ( = 0.31). With rotational stocking, there was the opportunity to harvest excess forage as hay in both MR and HR with a net value of US$52.90/ha ± 25.73 and $15.50/ha ± 25.73, respectively. Net returns per hectare did not differ ( = 0.30) between CG ($429 ± 63.0/ha) and MR ($479 ± 63.0/ha) but were increased ( < 0.01) by 107% by HR ($1,024 ± 63.0/ha). Using rotational grazing, stockpiled bermudagrass, and complementary cool-season annual grasses can drastically reduce winter feed requirements and simultaneously increase carrying capacity and net return.