Body, carcass, and steak dimensions of straightbred Holstein calves and Angus-sired calves from Holstein, Jersey, and crossbred beef dams.

Beef genetics are used with increasing frequency on commercial dairies. Although use of beef genetics improves calf value, variability has been reported in beef × dairy calf phenotype for traits related to muscularity and carcass composition. The objective of this study was to characterize morphometric and compositional differences between beef, beef × dairy, and dairy-fed cattle. Tested treatment groups included Angus-sired straightbred beef steers and heifers (A × B; n = 45), Angus × Holstein crossbreds (A × H; n = 15), Angus × Jersey crossbreds (A × J; n = 16), and straightbred Holsteins (H, n = 16). Cattle were started on trial at mean BW of 302 ±â€…29.9 kg and then fed at 196 ±â€…3.4 d. Morphometric measures were recorded every 28 d during the finishing period, ultrasound measures were recorded every 56 d, and morphometric carcass measures were recorded upon slaughter. Muscle biopsies were collected from the longissimus thoracis of a subset of steers (n = 43) every 56 d. Strip loins were collected from carcasses (n = 78) for further evaluation. Frame size measured as hip height, hip width, and body length was greatest for H cattle (P < 0.05), and A × H cattle had greater hip height than A × J cattle (P < 0.05). Relative to BW as a percentage of mature size, ribeye area of all cattle increased at a decreasing rate (negative quadratic term: P < 0.01), and all ultrasound measures of fat depots increased at an increasing rate (positive quadratic term: P < 0.01). Although no difference was observed in muscle fiber area across the finishing period from the longissimus thoracis (P = 0.80), H cattle had a more oxidative muscle phenotype than A × B cattle (P < 0.05). Additionally, H cattle had the smallest area of longissimus lumborum in the posterior strip loin, greatest length-to-width ratio of longissimus lumborum in the posterior strip loin, and least round circumference relative to round length (P < 0.05). Beef genetics improved muscularity in portions of the carcass distal to the longissimus thoracis.

Divergent selection of beef and dairy breeds has caused differences in skeletal size and muscularity. When calves from dairy systems enter the beef supply chain, variability in mature size and carcass composition are introduced. The objective of this study was to characterize morphometric differences in cattle populations with different proportions of beef and dairy genetics. Body measurements confirmed differences in mature size of beef-type cattle, dairy-type cattle, and beef × dairy cattle; Holstein influence was associated with greater skeletal growth. With advancing maturity, the rate of muscle accretion decreased quadratically while the rate of fat accretion increased quadratically. Although muscularity across all cattle types was similar in the longissimus near the last rib, differences were observed in the posterior end of the strip loin, the forearm, and the round. Differences in mature size, muscularity, and steak dimensions were observed between beef-type cattle, dairy-type cattle, and beef × dairy cattle.

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 ±â€…32.0 kg and concluded after 195 ±â€…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.

Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. The objectives of this study were to use an embryo transfer model 1) to investigate the effect of the dairy management system on beef genetics and 2) to directly compare the merit of Holstein and Jersey genetics for feedlot and carcass performance with modern beef genetics. Feedlot and carcass performance of straightbred beef cattle were similar regardless if the calf was raised in the traditional beef cow/calf system or if the calf was raised at a calf ranch. Based on greater daily live gain and carcass weight, Holstein maternal genetics had greater terminal merit than Jersey maternal genetics. Regardless of dam breed, dairy genetics increased carcass leanness. Minimal differences were detected between adjusted feed efficiency of beef and beef × dairy cattle, but underestimation of mature size of beef × dairy could have overestimated efficiency. Genetic differences were more impactful than differences between the conventional beef and dairy calfhood management systems on feedlot and carcass performance.