Two experiments were conducted with the opioid antagonist naloxone to determine the effect of opioid receptor blockade on hormone secretion in postpartum beef cows. In Exp. 1, nine anestrous postpartum beef cows were used to measure the effect of naloxone on serum luteinizing hormone (LH), cortisol and prolactin concentrations. Cows received either saline (n = 4) or 200 mg naloxone in saline (n...

BACKGROUND Endometritis, which is one of the most common diseases in dairy cows postpartum, causes severe economic losses, including increased open days, calving intervals, and numbers of services to achieve conception. AIM This study aimed to evaluate the ultrasound method and its agreement with the endometrium cytology method, which is used to diagnose cytological endometritis in beef cows....

The aim of the present study was to investigate the relation between different indices of milk yield andbody condition score (BCS) with the commencement of the luteal activity (C-LA) during the postpartumperiod in high producing dairy cows. Seventy-one multiparous healthy (free of detectable reproductivedisorders) Holstein dairy cows (mean peak milk yield = 56.7 ± 7.4 kg) were used in the prese...

The objective of this study was to determine the effect of genotype and week postpartum on serum concentrations of IGF-I, body condition score (BCS), BW, and ovarian function in beef cows. Cows from the following genotypes were utilized in two consecutive years: Angus (A x A; n = 9), Brahman (B x B; n = 10), Charolais (C x C; n = 12), Angus x Brahman (A x B; n = 22), Brahman x Charolais (B x C;...

Determining the immune responses to the development of endometritis during the peripartum period may assist in the development of more efficient reproductive management regimens for dairy herds. In this study, we compared the peripartum immune responses of dairy cows that develop endometritis by 4 weeks postpartum (n = 11) to cows that did not develop this disease (n = 19). Blood samples were c...

postpartum anestrous is one of the most important problems in the dairy industry in the world and especially in iran. the objective of present study was to compare the efficacy of two hormonal programs for recycling of postpartum anestrous cows. for this reason, 230 holstein cows from 4 similar dairy herds (with totally 2560 cow and unique management and feeding system) located on the suburb of...

An experiment was conducted to investigate the effect of different types of ovarian cycles on reproductive indices and blood metabolites in 61 Holstein cows. Blood samples were taken from each cow between day 12 and day 50 postpartum (PP). Serum progesterone concentrations were measured to determine the onset of luteal function and different types of luteal dysfunctions in cows. Serum glucose, ...

Three experiments were conducted to evaluate the effects of biostimulation (exposure to bulls or androgenized females) on various reproductive variables in suckled beef cows. Bulls or testosterone-treated cows (TTC) were introduced to cows, randomly allotted to one of four groups, within 72 h postpartum. In Exp. 1, Groups 1 and 3 were exposed to bulls and Groups 2 and 4 were exposed to TTC. In ...

Two experiments were conducted to evaluate reproductive responses to supplemental high-linoleate safflower seeds in postpartum beef cows. In Exp. 1, 18 primiparous, crossbred beef cows (411 +/- 24.3 kg of BW) were fed Foxtail millet hay starting 1 d postpartum at 1.68% of BW (DM basis) and a low-fat control (control: 63.7% cracked corn, 33.4% safflower seed meal, and 2.9% liquid molasses; DM ba...

the aim of the present study was to investigate the relation between different indices of milk yield andbody condition score (bcs) with the commencement of the luteal activity (c-la) during the postpartumperiod in high producing dairy cows. seventy-one multiparous healthy (free of detectable reproductivedisorders) holstein dairy cows (mean peak milk yield = 56.7 ± 7.4 kg) were used in the prese...