The objectives of this study were to evaluate replacing GnRH with hCG and the effects of 48-h calf removal (CR) on pregnancy rates of cows synchronized with the CO-Synch protocol. Suckled beef cows (n = 467) at two locations were assigned to treatment by breed, age, and calving date. Treatment included either GnRH with (n = 121) or without CR (n = 117) or hCG with (n = 115) or without CR (n = 114) using the CO-Synch protocol. On d 0 and 9, cows received either hCG (2,500 IU, i.m.) or GnRH (100 g, i.m.), and on d 7 all cows received PGF 2α (25 mg). At one location, blood samples were collected from all cows (n = 203) on d −14, −7, 0, 7, 9, and 16. Calves were removed on d 7 and returned on d 9 (48 h) from approximately half of the cows that received GnRH or hCG. Cows that were detected in estrus between d 6 and 9 were bred approximately 12 h later and received no further injections. Cows not observed in estrus by d 9 received a second injection of either GnRH or hCG and were timed-inseminated. The AI pregnancy rates for GnRH-treated cows with or without CR and hCGtreated cows with or without CR were 46, 49, 35, and 34%, respectively (P = 0.44). Pregnancy rates of cows
The objective of this study was to evaluate the influence of metabolizable protein (MP) restriction in mid-and/or late-gestation on meat quality, fatty acid profile, and carcass composition of progeny. Study Description Heifers were assigned to 2 levels of dietary protein (control [CON], 102% of MP requirements; or restricted [RES], 80% of MP requirements) at 2 stages of gestation (mid-gestation [MID] and late-gestation [LATE]) in a Balaam's Design crossover treatment structure resulting in 4 treatment combinations (CON-CON, CON-RES, RES-CON, RES-RES). After calving, cow-calf pairs were moved to pasture and managed as a common group through weaning. Following weaning, calves were finished in a GrowSafe feeding system to a common backfat endpoint. At harvest standard carcass data was collected, lean color (L*, a*, b*) was determined, and strip loins were collected for and fabricated into 1-inch steaks for determination of crude fat and tenderness at 3, 7, 14, and 21 days of aging using the Warner-Bratzler shear force method. An additional steak from a subsample of steer progeny (n = 24) was aged 3 days postmortem, frozen, and used for direct fatty acid methyl ester synthesis (determination of fatty acid profile). The 9-10-11 rib section of this same subsample of carcasses were removed from the left side of each carcass to determine carcass composition.
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