An evaluation of natuml twinning in beef cattle revealed that cows birthing twins had shorter (P c .Ol) gestation lengths, more (P e .Ol) retained placentas, more (P < .01) dystocia, more (P e .01) days to e m s , lower (P e .01) conception rates and more (P < .01) days to pregnancy than cows birthing singles. Days to estrus, conception rate and days to pregnancy were not affected by number of ...

BACKGROUND Beef cows herd accounts for 70% of the total energy used in the beef production system. However, there are still limited studies regarding improvement of production efficiency in this category, mainly in developing countries and in tropical areas. One of the limiting factors is the difficulty to obtain reliable estimates of weight variation in mature cows. This occurs due to the inte...

Managers of high producing dairy herds have known for some time that optimizing reproductive efficiency is an essential issue in maintaining profitability of a dairy herd. A recent survey by the University of Wisconsin Center for Dairy Profitability asked a random sample of 2,700 dairy producers in Wisconsin to rank the importance of different dairy issues to the future profitability of their b...

The present research was designed to evaluate the effects of pre and post-partum energy level and feeding pattern on the performance of crossbred dairy cows and their calves under farm conditions. A total of 16 crossbred dairy cows were divided into two equal groups on the basis of their body weight and milk production. One group was given 30% less and the another was given 30% more energy than...

The objectives were to examine the effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on expression of key endometrial genes and proteins regulating prostaglandin synthesis in lactating dairy cows. Two diets were fed, at about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) was compared with calcium salts of fish oil-enriched lipid (FO). Ovulation was s...

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 ...

Two experiments were conducted on postpartum suckled beef cows synchronized with Syncro-Mate B and artificially inseminated approximately 48 h after implant removal. In Exp. 1, cows (> or = 42 d postpartum at the timed AI) were randomly assigned to treated (n = 101) and control (n = 85) groups on d 12 after the timed AI. Treated cows received norgestomet/silicone implants that were left in situ...

In Exp. 1, we evaluated the effects of 2 lengths of progesterone exposure [CIDR (controlled intravaginal drug release); 7 vs. 14 d] before a modified CO-Synch protocol [50.0-microg injection of GnRH 6.5 d before a 25.0-mg injection of PGF(2alpha) followed by another injection of GnRH and fixed-time AI (TAI) 2 d after PGF(2alpha)], with or without temporary weaning (TW) before GnRH treatments, o...

The influences of body condition score (BCS) at calving and postpartum nutrition on endocrine and ovarian functions, and reproductive performance, were determined by randomly allocating thin (mean BCS = 4.4 +/- 0.1) or moderate condition (mean BCS = 5.1 +/- 0.1) Angus x Hereford primiparous cows to receive one of two nutritional treatments after calving. Cows were fed to gain either 0.45 kg/d (...

BACKGROUND The aim of this study was to detect the associations between bovine herpesvirus 1 (BHV-1) status of a herd and respiratory disease (BRD) occurrence and reproductive performance in pregnant heifers and cows. The association between management-related factors and higher BRD occurrence was also estimated. METHODS Serum samples, collected from cows and youngstock from 103 dairy cattle ...