BACKGROUND: Many additives have been recommended to calf feed but the effects of each supplement have been under investigation especially during weaning stress. OBJECTIVES: The effects of dietary supplementation of probiotic (Protexin) and chromium-methionine che- late (Cr-Met) on triiodothyronine (T3), thyroxine (T4), total protein, albumin, zinc, and gr...

The effect of cracked corn grain supplementation (3.5 kg/day) during 3 weeks before the expected calving date on milk production and composition, body condition score (BCS), metabolic and hormonal profiles and length of postpartum anoestrus was evaluated in multiparous Holstein dairy cows under grazing conditions (Energy supplemented group, n = 10; Control group, n = 10). Body condition score w...

One of the most dramatic events during the life of adult mammals is the transition into motherhood. This transition is accompanied by specific maternal behaviors, displayed by the mother, that ensure the survival and the well-being of her offspring. The execution of these behaviors is most likely accompanied by plastic changes in specific neuronal circuits, but these are still poorly defined. I...

Abiotic inputs such as photoperiod and temperature can regulate reproductive cyclicity in many species. When humans perturb this process by intervening in reproductive cycles, the ecological consequences may be profound. Trophic mismatches between birth pulse and resources in wildlife species may cascade toward decreased survival and threaten the viability of small populations. We followed fera...

Spring-calving Angus cows (n = 30) were used to evaluate changes in ruminal temperature (RuT) related to parturition and estrus. Cows were synchronized and artificially inseminated with semen from a single sire. Temperature boluses were placed in the rumen at 7.0 ± 0.2 mo of gestation. Boluses were programmed to transmit RuT every 15 min. Cows (BW = 623 ± 44 kg, BCS = 4.9 ± 0.4) calved during 3...

  Lead poisoning is the most significant preventable disease of environmental origin. Neurodevelopment is highly complex and there are numerous opportunities for lead to interfere with normal development. Lead acetate can disrupt the action of the CNS and the development of dendrites and axons. The present study was carried out to assess the effect of low-level lead exposure on memory and learn...

To determine if energy or phosphorus status would affect postpartum reproductive performance, we assigned primiparous heifers, six per group, to either high (135% NRC) or low (85% NRC) energy, and high (138% NRC) or low (98% NRC) phosphorus in a 2 x 2 factorial design. Treatments were continued from parturition through 84 days postpartum, after which standard diets were fed. The entire experime...

The objective of this study was to determine the relationships among daughter intramammary infections at first parturition and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Quarter milk samples from 958 daughters (in eight Pennsylvania herds and one Nebraska herd) of 182 Holstein sires were collected within a few days of first calving...

Our objective for this study was to determine the pattern of nutrient flux across the portal-drained viscera (PDV) and liver in ewes with varying numbers of fetuses. Catheters were placed in the hepatic portal vein, a branch of the hepatic vein, a mesenteric vein, and the abdominal aorta of ewes. Blood flow and net nutrient release across the PDV and liver were determined before exposure to ram...