Several dairy cows have been identified as partially deficient in UMP synthase. Although erythrocytes of normal cows contained 2.54 units of enzyme per ml, four cows were discovered with only 1.08 units per ml. Cows deficient in UMP synthase secreted milk with abnormally high levels of orotate, 300-1,000 micrograms of orotate per ml compared to 80 micrograms/ml for normal cows. The deficiency a...

The aim of this study was to evaluate the effect of body weight (BW) change during the early postpartum period and BW on day 50 post partum on the subsequent expression of estrus and fertility at first insemination before day 90 post partum. The data were derived from 1036 postpartum cows reaching 90 days in milk. The following data were recorded for each animal: lactation number, daily milk pr...

A model was developed for the economic evaluation of embryos for producing bull lines for use in commercial beef production. The fundamental concept underlying the model is that a cloned and sexed embryo of known genetic characteristics for beef traits is used to produce a bull. After reaching physiological maturity, the bull is used in natural matings. Equations relating feed energy requiremen...

An experiment was replicated over 2 yr to determine the effect of additional RUP and dietary fat from dried distillers grains plus solubles (DDGS; n = 2) or wet corn gluten feed (WCGF; n = 2) before breeding on primiparous cow reproduction and calf production. Over 2 yr, 134 postpartum, primiparous cows (429 ± 5 kg initial BW) were fed 1 of 2 isocaloric, approximately isonitrogenous diets in 1 ...

The fourth through sixth parity of 5- to 10-yr-old cows were used to evaluate trade-offs involved with sires of large mature size vs medium mature size in a terminal sire crossbreeding program and to characterize five breeds and their crosses for their potential as dam lines. Charolais and Red Poll bulls, representing large (L) and medium (M) mature size, respectively, were mated to cows repres...

This study was conducted to investigate the effect of clitoral massage on levels of estradiol (E2), testosterone (T), dehydroepiandrosterone sulphate (DHEA-S) and pregnancy rate in cows. For this purpose, 38 Holstein cows ranging from 3-6 years old were used. The cows were divided into two groups, as control (n=19) and application (n=19). The degree of intensity of oestrus expression was scored...

A study using 20 Holstein Friesian cows was conducted to investigate the influence of calf gender on metabolism during the transition period in dairy cattle. Blood samples were collected at three time points: 2–4 days prepartum (time 1), and 1 week and 2 weeks postpartum (time 2 and time 3 respectively). Serum samples obtained were analysed for total proteins, albumin, urea, glucose, non-esteri...

Reproductive efficiency is declining on U.S. dairy herds. There are numerous factors that affect reproductive efficiency on individual farms. These include heat detection rate, heat stress, semen quality, bull fertility, AI technique, nutrition, body condition score, clinical and subclinical mastitis, cow comfort, and many other factors related to whole farm management, individual farm managers...

Introduction Testicular temperature of bulls must be 2 to 6° C cooler than body temperature to allow normal spermatogenesis and maturation of sperm. Exposure of bulls to increased ambient temperatures results in reduced semen quality (Casady et al., 1953; Skinner and Louw, 1966; Meyerhoeffer et al., 1985). Local heating of the scrotum of bulls for a few days causes a reduction in the number of ...