Post-weaning management of modern dairy cattle genetics for beef production: a review.

The contribution of dairy steers to the U.S. fed beef supply has increased from 6.9% to 16.3% over the last two decades; in part, due to declining beef cow numbers and the increased use of sexed dairy semen to produce genetically superior replacement heifers from the best dairy cows. Raising dairy cattle for beef production offers unique opportunities and challenges when compared with feeding cattle from beef breeds. Dairy steers offer predictable and uniform finishing cattle performance (ADG, DMI, G:F) as a group and more desirable quality grades on average compared with their beef steer counterparts. However, dairy steers have lesser dressing percentages and yield 2%-12% less red meat compared with beef steers due to a greater ratio of bone to muscle, internal fat, organ size, and gastrointestinal tract weight. In addition, carcasses from dairy steers can present problems in the beef packing industry, with Holstein carcasses being longer and Jersey carcasses being lighter weight than carcasses from beef breeds. Beef × dairy crossbreeding strategies are being implemented on some dairy farms to increase the income generated from dairy bull calves, while beef × dairy crossbreeding strategies can also improve the G:F and red meat yield of beef produced from the U.S. dairy herd. This alternative model of beef production from the dairy herd is not without its challenges and has resulted in variable results thus far. Successful adoption of beef × dairy crossbreeding in the cattle industry will depend on the proper selection of beef sires that excel in calving ease, growth, muscling, and marbling traits to complement the dairy genetics involved in beef production.

The number of dairy steers contributing to the U.S. fed beef supply has increased from 6.9% to 16.3% over the last two decades. Raising dairy cattle breeds for beef production offers unique opportunities and challenges when compared with feeding beef cattle breeds. Dairy steers offer predictable and uniform finishing cattle performance (ADG, DMI, G:F) as a group and more desirable quality grades on average compared with their beef steer counterparts. Dairy steers yield less red meat compared with beef steers due to a greater ratio of bone to muscle, internal fat, organ size, and gastrointestinal tract weight. The use of growth-promoting technologies such as hormonal implants and ß-adrenergic agonists can help improve finishing cattle performance and increase the red meat yield of dairy-influenced steers. In addition, beef × dairy crossbreeding strategies are being implemented on some dairy farms to increase the income generated from bull calves, while beef × dairy crossbreeding strategies can also improve the gain:feed and red meat yield of beef produced from the U.S. dairy herd. Successful adoption of beef × dairy crossbreeding in the cattle industry will depend on the proper selection of beef sires to complement the challenges and opportunities experienced with dairy genetics for beef production. Early calfhood management practices should be investigated further to determine their impacts on the subsequent finishing performance and carcass characteristics of calves produced by dairy farms for beef production.

Growth performance, carcass characteristics, and fatty acid composition of Angus- and Wagyu-sired finishing cattle fed for a similar days on feed or body weight endpoint.

This study evaluated the feedlot performance, carcass characteristics, and fatty acid (FA) composition of Wagyu-sired and Angus-sired cattle at a similar days on feed (D) or body weight (B) endpoint. Wagyu-sired steers and heifers (WA) from two different sires, selected for either growth (G) or marbling (M), were compared with Angus-sired steers (AN, n = 13) in two independent incomplete-block design experiments at a similar days on feed (DOF; WA-GD, n = 9; WA-MD, n = 12) in experiment 1 or similar final body weight (BW; WA-GB, n = 9; WA-MB, n = 13) in experiment 2. Cattle were offered a corn silage-based growing diet for 119 d before being transitioned over 3 wk to a finishing diet. Data were analyzed as a randomized incomplete block design. In experiment 1, AN and WA-GD cattle had a greater (P < 0.01) off-test BW and average daily gain (ADGP < 0.04) than WA-MD cattle and AN had a greater dry matter intake (DMI; P < 0.02) than WA-GD and WA-MD cattle. The AN and WA-GD cattle had a greater carcass weight (P < 0.02) than WA-MD cattle. Percent kidney, pelvic, and heart fat (KPH) was greatest (P < 0.01) for WA-MD cattle, followed by WA-GD cattle, and lastly AN cattle. Total lipid (P < 0.03) and polyunsaturated FA (PUFA; P < 0.01) percentage were greater for WA-MD-cattle than AN and WA-GD cattle, as they tended (P = 0.11) to have the greatest 12th rib marbling score. In experiment 2, AN-cattle needed fewer (P < 0.01) DOF and had a greater (P ≤ 0.02) ADG, DMI, and gain:feed than WA-GB- and WA-MB-cattle. The WA-MB-cattle had a greater (P < 0.01) 12th and 6th rib marbling score, USDA quality grade, and 6th rib backfat thickness than AN-cattle. Compared with AN cattle, WA-GB cattle had a greater (P ≤ 0.01) percent KPH and lesser (P ≤ 0.03) rib thickness. The WA-MB-cattle had a greater (P ≤ 0.01) concentration of total lipid and PUFA than AN- and WA-GB-cattle, and lesser saturated FA (SFA; P < 0.01) concentration than AN-cattle in the longissimus muscle (LM). The 6th rib location of the LM had a greater (P ≤ 0.01) percentage of total lipid and SFA, but less (P < 0.03) MUFA compared with the 12th rib location. In conclusion, Wagyu-sired cattle selected for marbling potential had a lesser ADG, DMI, more marbling, more PUFA, and less SFA in the LM than Angus-sired cattle regardless of slaughter endpoint. Wagyu-sired cattle selected for growth potential had a similar ADG and carcass characteristics compared with Angus-sired cattle when fed for a similar number of days on feed.

Wagyu-sired steers and heifers (WA) from two different sires, selected for either growth (G) or marbling (M), and Angus-sired steers (AN) were fed for a similar days on feed (D) or to a similar final body weight (B) in two independent experiments. In experiment 1, Angus-sired steers were compared with Wagyu-sired steers and heifers when fed for a similar number of days on feed (DOF; WA-GD and WA-MD) and in experiment 2, AN were compared with Wagyu-sired steers and heifers at a similar final body weight (BW; WA-GB and WA-MB). In experiment 1, AN and WA-GD cattle had a greater rate of gain and final BW compared with WA-MD cattle. AN cattle consumed more feed compared with Wagyu-sired cattle. WA-MD had the greatest amount of kidney fat and polyunsaturated fatty acid (FA) compared with AN and WA-GD cattle. In experiment 2, AN cattle had a greater rate of gain, feed intake, with fewer DOF compared with Wagyu-sired cattle. At a similar final BW, WA-MB cattle deposited more kidney fat, marbling at the 6th- and 12th-rib, and backfat at the 6th-rib compared with AN cattle. The FA profile of the longissimus muscle from WA-MB cattle had more polyunsaturated FA, with less saturated FA compared with AN cattle. The resulting feedlot performance and carcass characteristics vary depending on the selection of Wagyu sire for growth or marbling ability.

Maternal Supply of Fatty Acids during Late Gestation on Offspring's Growth, Metabolism, and Carcass Characteristics in Sheep.

Lambs born from dams supplemented with different sources of fatty acids (FA) during late gestation have a different growth rate and plasma glucose concentration. The main objectives of this experiment were to evaluate the effect of supplementing different sources of FA during late gestation on offspring plasma metabolite concentrations, growth, and on a glucose tolerance test (GTT) during the finishing phase. Fifty-four lambs (18 pens, 3 lambs/pen) were born from ewes supplemented during late gestation with one of three treatments: (1) no FA (NF); (2) a source of monounsaturated FA (PDS, 1.01% of Ca salts); or (3) a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (EDS, 1.01% of Ca salts containing). At birth (day 0), supplementation ceased, and all ewes and lambs were placed in a common pen. On day 60, lambs were weaned, grouped by sex, blocked by body weight (BW), and placed on a common finishing diet for 54 days (FP). One lamb per pen was used for the GTT after the FP. There was a tendency for FA × Sex × Day interaction (p = 0.08) on lamb growth during the finishing period, with PDS females being heavier than PDS males, while EDS males were heavier than EDS females at day 60. There was a tendency for FA × Sex interaction (p = 0.06) for plasma insulin concentration for the GTT. Plasma insulin concentration of wethers increased as FA unsaturation degree increased during the GTT; the opposite happened with the plasma insulin concentration of female lambs. In conclusion, FA supplementation during late gestation tended to modified growth and insulin response to a GTT; these changes differed with the degree of FA unsaturation of the supplement and lamb sex.

The effects of age, sex, and hot carcass weight on cooked lamb flavor and off-flavor in four muscle cuts.

The present study used 48 lambs originating from three different locations in the Western United States (16 lambs per location; 8 ewes and 8 wethers per location). Each consisting of similar breed composition (Suffolk cross) that were selected to represent weight by age at harvest treatments: light weight carcasses at 5 mo (LW5, 31.81 ± 1.88 kg), light weight carcasses at 12 mo (LW12, 35.09 ± 4.45 kg), heavy weight carcasses at 12 mo (HW12, 57.89 ± 4.70 kg) with different carcass weight compositions. Older heavy weight lambs (HW12) had greater (P ≤ 0.01) hot carcass weight, ribeye area, backfat and body wall thickness, and yield grade compared with light weight lamb carcasses (LW5 and LW12). The longissimus thoracis longissimus thoracis (LT) from older lamb carcasses (LW12 and HW12) had a greater (P ≤ 0.01) total lipid percentage compared with younger lamb carcasses (LW5). Across harvest weight and age treatments, wether carcasses had greater (P ≤ 0.05) total lipid percentage compared with ewe carcasses. Slice shear force values were greater (P ≤ 0.01) for both the LT and semimembranosus from older lambs (LW12 and HW12) compared with LW5 lambs, with no differences between ewes and wethers. Lamb flavor intensity was greater (P ≤ 0.05) for the LT of LW12 lambs and tended (P = 0.08) to be greater for HW12 lambs, compared with the LT from LW5 lambs. The off-flavor intensity of the LT was greater (P ≤ 0.01) for older lambs (LW12 and HW12) compared with LW5 lambs. Interestingly, the lamb flavor and off-flavor intensity scores of the ground shoulder exhibited a treatment × sex interaction. Lamb flavor intensity of LW12 lamb was greater (P ≤ 0.05) from ewes compared with wethers, whereas wethers had a greater (P ≤ 0.05) lamb flavor intensity compared with ewes for HW12 lambs, and LW12 ewe lambs had a greater (P ≤ 0.05) off-flavor intensity compared with all other treatment × sex treatment combinations. Overall, lambs in the present study possessed a mild lamb flavor, typically with greater lamb flavor and off-flavor intensities for older animals; while slice shear force and LT lipid percentage increased as animal age increased at the time of harvest.

Effect of energy source and level, animal age, and sex on the flavor profile of sheep meat.

The effects of dietary energy source, energy level, sheep age, and sheep sex on flavor and off-flavor intensity were evaluated. Consumer panelists, with previous lamb-eating experience, assessed lamb flavor and off-flavor intensity on a 100-point, end-anchored scale (0 = very mild to 100 = very intense), with off-flavor being defined as anything different than lamb flavor. Lamb longissimus thoracis (LT) and whole, boneless ground shoulder (GS) formed into patties were evaluated. Trial 1 was a randomized complete block design with a 3 × 2 factorial arrangement of treatments. Sheep age (ewe lambs, yearling ewes, and mature ewes; n = 16/age) and ad libitum access to diets [alfalfa pellets (AP) or whole-shelled corn (WSC100)] were treatments. The LT from mature ewes had a greater (P ≤ 0.02) off-flavor intensity when compared with yearling ewes and ewe lambs. Ground shoulder from sheep raised on AP had a greater lamb flavor (P ≤ 0.04) and off-flavor (P ≤ 0.04) intensity than GS from sheep consuming WSC100. Trial 2 was a randomized complete block design with a 3 × 2 × 2 factorial arrangement of treatments. Three dietary treatments [AP, WSC100, and restricted intake of whole-shelled corn to 85% of ad libitum (WSC85)], lamb sex (ewes and wethers; n = 48/sex), and lamb age [short fed, 177 ± 16.6 d of age and 93 ± 20.5 d on feed (DOF); long fed, 294 ± 7.0 d of age and 219 ± 3.8 DOF]. Flavor intensity of the LT was greater (P ≤ 0.05) from lambs offered AP when compared with lambs offered WSC85, whereas lamb flavor of the LT from lambs fed WSC100 was intermediate and not different from the lamb flavor of the LT of lambs fed AP or WSC85. The LT of long-fed lambs had a greater (P ≤ 0.01) lamb flavor and off-flavor intensity when compared with short-fed lambs. Lambs offered AP resulted in a GS with greater lamb flavor intensity (P ≤ 0.01) when compared with lambs offered WSC85 and WSC100, with no diet influence on GS off-flavor intensity. Long-fed lambs produced GS with a greater lamb flavor (P ≤ 0.01) and off-flavor (P ≤ 0.01) intensity when compared with GS from short-fed lambs. Results from the two trials indicate lamb flavor and off-flavor intensity were greater from sheep offered a high-forage (AP) diet when compared with a high-concentrate (WSC) diet. Lamb flavor intensity increased as age of the sheep at harvest increased, suggesting dietary management and associated age-related effects at harvest will influence consumer perception of lamb flavor.

Opportunities to improve the accuracy of the United States Department of Agriculture beef yield grade equation through precision agriculture.

The U.S. Department of Agriculture (USDA) yield grade (YG) equation is used to predict the retail yield of beef carcasses, which facilitates a more accurate payment for cattle when they are sold on a grid pricing system that considers carcass composition instead of body weight alone. The current USDA YG equation was developed over 50 yr ago. Arguably, the population of cattle used to develop the YG equation is different than the current diverse U.S. beef cattle supply today. The objectives of this manuscript are to promote the adoption and use of precision agriculture technologies (i.e., camera grading and electronic animal identification) throughout the U.S. beef supply chain as a means to enhance the ability of the USDA YG equation to more accurately predict the retail yield across the population of cattle that contributes to the current U.S. beef supply. Camera grading has improved the accuracy of determining beef carcass retail yield; however, the use of electronic animal identification would allow for additional information to be passed back and forth between the packer, cattle feeder, and producer. Information, such as sex, genetics, medical treatment history, diets consumed, and growth promotant administration, as well as other information could be used to create additional variables for a new augmented USDA YG equation. Herein, fabrication yields demonstrated a 5.6 USDA YG and 12.8% boneless closely trimmed retail cut difference between actual cutout measurements and calculated values from the USDA YG equation for Jersey-influenced cattle. Evidence of such disparities between calculated and actual values warrants a reevaluation of the USDA YG system and consideration for implementing advancements in precision agriculture to improve the prediction of beef carcass retail yield to more accurately account for the large amount of variation in beef carcass retail yield from the cattle in the United States.

Evaluation of feedlot performance, carcass characteristics, carcass retail cut distribution, Warner-Bratzler shear force, and fatty acid composition of purebred Jersey and crossbred Jersey steers.

Feedlot performance, carcass yield, fatty acid composition, and tenderness of crossbred Jersey steers compared with purebred Jersey steers was investigated. Purebred Jersey (n = 21) and crossbred Jersey steers sired by Angus (n = 9), SimAngus (n = 10), and Red Wagyu (n = 15) bulls were assessed. Adjusted to a common initial body weight (BW), crossbred Jersey steers had a greater rate of BW gain (P ≤ 0.01) compared with purebred Jersey steers. Angus sired steers had a greater daily dry matter intake (P ≤ 0.01) compared with Wagyu and Jersey sired steers, whereas SimAngus sired steers had a greater daily dry matter intake compared with Jersey sired steers. Wagyu sired steers were more feed efficient (P ≤ 0.03) compared with Jersey sired steers. Even with a greater (P ≤ 0.01) number of days on feed, off-test BW of purebred Jersey steers was less (P ≤ 0.01) compared with crossbred Jersey steers. Adjusted to a common hot carcass weight, Angus sired steers had a greater backfat thickness (P ≤ 0.01) compared with steers from the other sire breeds. Kidney fat percentage (P ≤ 0.01) was greatest for Jersey sired steers, with SimAngus and Wagyu sired steers being intermediate, and the lowest for Angus sired steers. Carcasses from Angus and Wagyu sired steers had a greater marbling score (P ≤ 0.03) compared with carcasses from Jersey sired steers. Carcasses from Wagyu sired steers had a greater (P ≤ 0.01) total red meat yield compared with Angus and Jersey sired steers, whereas SimAngus sired steers had a greater total red meat yield compared with Jersey sired steers. Carcasses from Angus sired steers tended (P = 0.07) to have a greater percentage of fat trim compared with Wagyu sired steer carcasses. There were no sire breed differences (P = 0.38) for the percentage of total bone from the carcasses. Tenderness, measured by Warner-Bratzler shear force (WBSF), was improved (P ≤ 0.01) with 14 d of postmortem aging compared with 7 d. Wagyu and SimAngus sired steers produced steaks with a lesser (P ≤ 0.01) WBSF compared with steaks from Angus and Jersey sired steers. Steaks from Angus sired steers tended (P = 0.10) to have a greater percentage of total lipid and had a greater (P ≤ 0.05) percentage of 16:0 compared with steaks from Jersey sired steers. Overall, crossbred Jersey steers improved economically relevant production parameters of feedlot performance, carcass quality, carcass yield, and instrumental predictors of eating quality compared with purebred Jersey steers.