The effects of winter supplement type on growth and pregnancy rate of fall-born, yearling heifers was investigated over 2 consecutive years. During both years, heifers were stratified by breed (Braford and Brangus-crossbred) and BW and randomly assigned to one of two treatments consisting of (1) wheat middling-based range cube, or (2) molasses-cottonseed meal slurry (n=34 and 24 heifers/treatme...

The objective of this study was to investigate the effect of supplemental tribasic copper chloride (TBCC) vs Cu sulfate on the Cu status and voluntary forage intake of growing heifers fed forage-based diets. Twenty-four crossbred heifers were stratified by weight and randomly allotted to individual pens. Heifers were provided free-choice access to ground grass hay (8.0 and 54.0% CP and TDN, res...

Forty-six crossbred Hereford heifers were allotted into five experimental groups. Fenprostalene, a prostaglandin analogue, was administered to induce abortion and (or) to regress the corpus luteum (CL) in four groups of heifers about 75 d after conception. The four groups were 1) pregnant heifers, 2) pregnant heifers with the ovary contralateral to the gravid uterine horn removed 24 h after fen...

BACKGROUND Heifers can calve down with intramammary infections (IMI) and udder damage. This will have a negative impact on their longevity, future milk yield and financial return. Co-housed pre-weaned calves that are fed fresh milk have the opportunity to suckle each other's teats and may infect udders of fellow heifer calves with pathogens present in milk. The prevalence of IMI in pregnant hei...

The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (Ta) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agri...

Stocking density is one example of management that may impact welfare and reproductive efficiency of beef females in Oregon cows-calf systems. In spring-calving herds, replacement heifers are weaned late in the fall and exposed to their first breeding season the following spring/summer. Therefore, these heifers are often developed in drylot systems during the winter/early spring to facilitate m...

Five trials were conducted with 958 virgin beef heifers to evaluate the effects of various breeding management methods on pregnancy rate at synchronized estrus and during a 45-day artificial insemination (AI) season. Synchronization was achieved with the progestin treatment regimen Syncro-Mate-B (SMB). Pregnancy rate at first service and cumulative pregnancy rate were affected (P less than .01)...

The objectives of this study were to evaluate the effects of immunization against recombinant GnRH fusion proteins and growth promotants on onset of puberty, feedlot performance, and carcass characteristics of beef heifers. Heifers were immunized against an ovalbumin fusion protein containing 7 GnRH peptides (oGnRH, n = 12), a thioredoxin fusion protein containing 7 GnRH peptides (tGnRH, n = 12...

Two studies were conducted to evaluate the effects of postweaning management of British crossbred heifers on growth and reproduction. In Exp. 1, 239 spring-born, crossbred heifers were stratified by weaning BW (234 ± 1 kg) and allotted randomly to 1 of 2 treatments. Treatments were fed at a rate equivalent to 1.14 kg/d while grazing dormant forage (6.5% CP and 80% NDF, DM basis) and were 1) 36%...

A 3-yr study was conducted with spring-born heifers (n = 240) to determine the effects of developing heifers to either 55 or 60% of mature BW at breeding on reproduction and calf production responses. A concurrent study was also conducted with summer-born heifers (n = 146) to examine effects of breeding heifers with the mature cow herd or 1 mo earlier on reproduction and calf production variabl...