T.A. Thrift

REVIEW: Update on preconditioning beef calves prior to sale by cow-calf producers1

ABSTRACT Preconditioning is designed to reduce incidence of bovine respiratory disease by increasing the immunity of the calf in preparation for the stress of weaning and shipping as calves move from their birth location through the stocker and feedlot phases of the beef production cycle. Results summarized from various studies indicate buyers paid more for preconditioned relative to nonpreconditioned calves (premium values ranged from

Ramifications of Weaning Spring- and Fall-Born Calves Early or Late Relative to Weaning at Conventional Ages1

1.43 to

Effects of preslaughter electrolyte supplementation on the hydration and meat quality of cull dairy cows

6.15/45.4 kg for studies that assessed statistical significance of values); however, premiums paid for preconditioned calves do not necessarily result in increased net profit for cow-calf producers (net profit values ranged from -

Effects of Days on Concentrate Feed and Postmortem Aging on Carcass and Palatability Characteristics of Selected Muscles from Cull Beef Cows1

89.92 to

The Issue of Carcass Tenderness Expressed by Cattle Varying in Bos indicus Inheritance1

53.71/calf). To realize the greatest monetary benefit from preconditioning, cow-calf producers should develop a reputation for integrity and market calves through special preconditioning sales.

CASE STUDY: Use of dried distillers grains, soybean hulls, or both to background beef calves fed bahiagrass hay

Results summarized for spring- and fall-born calves indicate that, in general, if early weaned (EW) calves are fed some form of concentrate diet from time of EW until age at which they would be conventionally weaned (CW), their BW will be equal to or greater than the BW of calves allowed to nurse their dams and CW. Feedlot ADG and carcass weight tend to be less, carcass yield grade is equal, and the percentage of carcasses grading greater than or equal to Low Choice tend to be equal to or greater for EW cattle relative to CW cattle. When the stress of lactation is removed by EW, cows gain BW and condition and begin to cycle; pregnancy rate is increased. Subsequent preweaning productivity is similar for cows that were weaned early or late (LW) as calves relative to cows that were CW.

Longevity Attributes of Bos indicus × Bos taurus Crossbred Cows1

ABSTRACT Two studies were conducted to evaluate the effect of preslaughter electrolyte supplementation on weight loss, hydration, and beef quality of cull dairy cows. Cows were withheld from feed before slaughter for 36 or 24 h, and ambient temperature ranged from 22 to 32°C or from 12 to 17°C for Exp. 1 and 2, respectively. In Exp. 1, cull dairy cows (n = 60) were given the control treatment (CON; n = 30) or the on-farm electrolyte supplementation treatment (PRE; n = 30). Cows on the PRE treatment tended to have a greater (P = 0.06) decrease in packed cell volume than did CON cows throughout the preslaughter period. Longissimus samples from PRE cows exhibited greater drip loss (P = 0.04) and tended (P = 0.06) to have a lower 24-h pH than did samples from CON cows. In Exp. 2, cull dairy cows (n = 46) were given the CON (n = 16), PRE (n = 16), or posttransportation electrolyte supplementation treatment (n = 14). Cows on the PRE treatment tended to have a lower (P = 0.06) percentage of weight loss during transport than did untreated cows. Results from both experiments demonstrated the potential for preslaughter electrolyte supplementation to attenuate the negative effects of stressors on cull dairy cows, but supplementation appears to be more effective during periods of hot weather and extended feed withdrawal.

Review: The Issue of Dystocia Expressed when Sires Varying in Percent Bos indicus Inheritance Are Mated to Bos taurus Females1

Twenty-four beef cows were selected to examine the effects of concentrate feeding on performance and to examine the effects of concentrate feeding and postmortem aging (10 or 20 d) on the triceps brachii lateral and long heads, infraspinatus, longissimus lumborum, psoas major, gluteus medius, tensor fascia latae, rectus femoris, and vastus lateralis. Cows were randomly assigned to a concentrate diet for 0, 42, or 84 d. Carcass characteristics were measured and Warner-Bratzler shear force, sensory evaluation, and collagen analyses were performed on selected muscles. Cow BW, ADG, and BCS increased (P 0.05) sensory off-flavor detection. Concentrate feeding of cull cows for 84 d improved carcass characteristics and the tenderness of several muscles. These muscles may be aged for 20 d postmortem to achieve maximal tenderness without detrimental off-flavor production.

Expected Versus Realized Progeny Differences for Various Beef Cattle Traits1

Abstract This review reveals that relative to Bos taurus cattle, cattle varying in Bos indicus inheritance, especially cattle that are > 1/2 Bos indicus inheritance, lack carcass tenderness. Because consumers are willing to pay for more tender beef, it seems imperative that the commercial beef cattle industry should refrain from producing cattle that are > 1/2 Bos indicus inheritance. Because of their Superior preweaning maternal performance, F 1 Bos indicus ♂ × Bos taurus 9 females and their resulting contemporary F 1 steer mates will continue to be produced by the commercial beef cattle industry in the Southeast and Golf Coast areas of the U.S. Further, as progeny testing for tenderness is expensive, it is suggested that the F 1 Bos indicus ♂ x Bos taurus 9 steers be identified by the commercial beef cattle industry so that the packing/ retail industries can utilize existing postmortem technology (electrical stimulation, blade tenderization, extended aging, calcium chloride injections) to partially alleviate the lack of tenderness expressed by carcasses resulting from these cattle.

Comparison of feed additive technologies for preconditioning of weaned beef calves.

ABSTRACT Two experiments were conducted to evaluate dried distillers grains (DDG), soybean hulls (SBH), and a slow-release urea (SRU) product as supplements to background beef steer calves. In both experiments, 56 Angus steers were individually supplemented for 42 d and provided ad libitum access to bahiagrass (Paspalum notatum) hay. On d 0, 14, 28, and 42, BW were recorded and blood samples were collected. In Exp. 1, steers (BW = 236 ± 26 kg) were randomly allotted to 1 of 4 supplement treatments: 1) DDG (1.19 kg/d), 2) DDG+SRU (1.19 kg/d of DDG + 45.5 g/d of SRU), 3) SBH (2.63 kg/d), or 4) SBH+SRU (2.63 kg/d of SBH + 45.5 g/d of SRU). Final BW did not differ (P ≥ 0.74); however, 42-d BW gain was greater (P = 0.05) and estimated mean total DMI was greater (P