A 2-sample regime was used to measure whole milk progesterone concentration on the day of oestrus and insemination (Day 0) and 6 days later (Day 6) in a sample of 50 primiparous and 100 multiparous suckling beef cows. Exposure to teaser bulls and observation by cattlemen identified the occurrence of oestrus. Three sets of criteria used to define ovulatory oestrus were compared: a) milk progeste...

After parturition, dairy cows suffer from an intense energy deficit due to the onset of copious milk secretion and an inadequate increase in voluntary food intake. We previously showed that this energy deficit contributes to a decline in plasma leptin. This decline mirrors that of plasma insulin, but is reciprocal to the profile of plasma growth hormone (GH), suggesting that both hormones may r...

The objectives of this study were to evaluate the effects of daily top-dressing (individually feeding on the top of the total mixed ration) with rumen-protected methionine (RPM) from 30 ± 3 until 126 ± 3 Days in milk on productive and reproductive performance in lactating dairy cows. A total of 309 lactating dairy Holstein cows (138 primiparous and 171 multiparous) were randomly assigned to tre...

The objective of the present field study was to establish the beneficial effects of re-insemination of non-pregnant cows using ultrasonography 20 to 23 days after the artificial insemination. A total of 245 Japanese Black cows were artificially inseminated and early pregnancy diagnosis (EPD) was performed on 92 cows 20 days after insemination, using ultrasonography. The remaining 153 cows were ...

A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related defects in market beef and dairy cows and bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; beef and dairy). Ove...

this study had the objective of determining the fertility and calving ease of small holder indigenous cattle herds inseminated with imported semen from proven sires. sixty one indigenous cows of different breed origin (bunaji, sokoto gudali and rahaji) were selected from different herds across jigawa state-nigeria, and were used for this study. the selected dams were inseminated with semen from...

J. Anim. Sci. Vol. 88, E-Suppl. 2/J. Dairy Sci. Vol. 93, E-Suppl. 1/Poult. Sci. Vol. 89, E-Suppl. 1 W277 Effects of treatments with hCG or GnRH on serum progesterone (P4) and conception rates (CR) in lactating dairy cows submitted to timed artificial insemination (AI) or embryo transfer (ET). P. Justolin*1, P. Morelli1, M. Reis1, O. Sá Filho1, F. Aragon2, M. Veras2, S. Soriano3, and J. L. Vasco...

“Gradual dryoff” is the practice of skipping some milkings before cessation of milking a cow at the end of lactation. I was taught in agricultural and vet school classes that this was to be avoided; abrupt dryoff no skipped milkings is physiologically superior for the cow. Nevertheless, like most dairy veterinarians, I experienced clients using gradual dryoff sometimes. When I was a resident at...

The objective of this study was to investigate factors that influence the success of resynchronization protocols for bovines with and without progesterone supplementation. Cow synchronized and not found pregnant were randomly assigned to two resynchronization protocols: ovsynch without progesterone (P4) supplementation (n = 66) or with exogenous P4 administered from Days 0 to 7 (n = 67). Proges...