Our objectives were to determine pregnancy rate, fetal loss, and number of calves born in beef cattle after a fixed-time transfer of an embryo 7 d after a fixed-time artificial insemination (TAI) of cows (Exp. 1) and after transfer of 2 demi-embryos into a single heifer recipient (Exp. 2). In Exp. 1 after synchronization of ovulation, during 2 yr, 297 suckled beef cows were assigned randomly to...

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...

The most recent issue of the Journal of Dairy Science has several papers regarding decreased fertility in dairy cattle, and the efforts to develop hormonal treatment regimens to improve fertility. Much of the recent work focuses on trying to reduce loss of fetuses during early pregnancy. This prompted me to search the literature about this extensive and important subject area. I suspect that Ut...

The objectives of this study were to relate concentrations of plasma (PUN) and milk (MUN) urea nitrogen to pregnancy rate in dairy cows and compare various methods of analysis and preparation of milk for measuring MUN. In two experiments, blood or milk samples were collected on the day of AI from Holstein cows (n = 160 and n = 155, respectively). Three methods of MUN analysis were compared. Two...

The objective was to examine effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on reproductive responses in lactating dairy cows. Beginning at approximately 17 d in milk (DIM), a comparison was made of isoenergetic diets comprising supplementary lipids of whole cottonseed vs. calcium salts of fish oil enriched lipid (FO). Ovulation was synchronized in cows with a presynch...

The objective of this study was to determine the effects of two different time of GnRH injection after artificial insemination (A.I) (d 6 and d 12) on reproductive performances of Holstein cows during the warm season.  Cows randomly assigned to treatments 1) No GnRH injection (control, n = 300),2) GnRH injection at day 6 after A.I (G6, n=300) and 3) GnRH injection at day 12 after A.I (G12, n=30...

Improved reproductive efficiency is the outcome of herd management and could involve a decision to choose between artificial insemination (AI) and natural service (NS). The objective of the present study was to determine the time of ovulation and pregnancy rate (PR) following timed AI (TAI) and NS, and frequency of TAI of two different management systems in oestrus synchronized Kedah-Kelantan (...

A total of 198 cows were randomly assigned to treatment with a single intramuscular injection of 10 ml of a preparation containing vitamin E and selenium or placebo 3 wk before expected parturition. Incidence of retained fetal membranes was 3.0% for the treated group and 10.1% for the control group (P=0.06). Administration of MU-SE also increased the percentage of cows pregnant to the first ser...

Considering dairy cattle reproduction, profitability is maximized when every cow gets pregnant at her optimal time after calving (at a low cost). This optimal time of conception has consequences for economically optimal breeding decisions and the value of a pregnancy, both a new pregnancy and a loss of pregnancy (abortion). Some cows are more important to get pregnant than others. This paper di...

BackgroundThe maternal cardiovascular system undergoes dramatic adaptations during the volume overload of pregnancy. Blood is increased nearly 40% with enlargement cardiac chambers and heart valves. Aortic diameter increases pregnancy, even greater in multiparous women. How aortic elastin collagen are altered this remodeling poorly understood. Of particular interest elastin—whose gene thought t...