Straightbred and crossbred heifers (165) and cows (241) that were nonpregnant after exposure to fertile bulls for two consecutive breeding periods of 45 to 60 d (repeat breeders) and contemporary cows (102) that had produced a calf in the previous calving season (controls) were placed with bulls and were observed for mating. Repeat-breeder and control females were slaughtered at 2 to 51 d postm...

This study was conducted to investigate the effect of the interval between the onset of spontaneous estrus and artificial insemination (AI) on reproductive performance and calf sex ratio in repeat breeder Holstein cows. Two hundred eighty lactating Holstein cows were used in this study. The animals were artificially inseminated at different times (0–6, 7–12, 13–18, or 19–24 h) after the onset o...

bovine genital campylobacteriosis is one of the most economically important diseases of dairy cattleresulting in lowered fertility, embryo mortality and abortion, repeated returns to service, reduced pregnancyrates and extended calving intervals. while the occurrence of repeat breeding syndrome and abortions arereported from many iranian dairy cattle farms, little information is available regar...

The objective of this study was to investigate the effect of antibiotic treatment on pregnancy rate in repeat breeder dairy crossbred cows. Based upon culture and sensitivity test, cows were assigned into two groups. Genta (n = 10) cows were treated with gentamycin (100 mg/ml) and ENRO (n = 12) cows were treated with enrofloxacin (100 mg/ml) intramuscularly 4 ml/100 kg body weight and intra-ute...

The present study was designed to evaluate the effect of Ovsynch protocol in repeat breeding crossbred Jersey cows. A total of thirty four repeat breeding cross bred Jersey cows were subjected to Ovsynch protocol with timed artificial insemination. The pregnancy rate in Ovsynch protocol was 58.82 per cent where as it was 29.41 per cent in control group. Thus, the Ovsynch protocol can be effecti...

Poor reproductive efficiency is a worldwide problem that has affected the dairy industry during the last several decades. In an attempt to explain the changes in reproductive physiology caused by high milk production, a model of elevated steroid metabolism in lactating dairy cows has been proposed. A slow increase in levels and low peak levels of estradiol (E₂) and progesterone (P₄) characteriz...

Present study was carried out on some reported repeat breeder individuals (n=08) of nondescript cows at Para-veterinary hospital, University of veterinary and Animal Sciences, Ravi Campus, Pattoki. Nondescript cows has major share, which is approximately 70% in cattle farming in Pakistan. Chromosomal preparations were made using blood culture from animals under study. About 50 metaphase spreads...