this prospective longitudinal study deals with the associations between digital disorders and reproduction indices in dairy cattle on a farm in the vicinity of tehran. it was carried out on 225 postparturient holstein heifers. the evaluation of lameness due to digital disorders on postpartum period of heifers were done and after diagnosis of lameness (based on a 5 points lameness scoring system...

Objectives were to develop a timed artificial insemination (TAI) resynchronization program to improve pregnancy per AI and to evaluate responses of circulating progesterone and pregnancy-associated glycoproteins in lactating cows. Cows (n=1,578) were presynchronized with 2 injections of PGF2alpha, given 14 d apart starting on d 45+/-3 postpartum, followed by Ovsynch [2 injections of GnRH 7 d be...

To compare 2 strategies for systematically resynchronizing ovulation, lactating Holstein cows (n = 763) at various days in milk and prior artificial insemination services were assigned randomly at timed AI (TAI) to receive the first GnRH injection of Ovsynch 26 (D26) or 33 (D33) d after TAI to resynchronize ovulation (Resynch) in cows failing to conceive. Cows in the D26 treatment received GnRH...

The association of birth type (single vs. double) and pregnancy type (single vs. double) with lactation performance and lactation curve was investigated in Holstein cows in Iran. Data of 243298 lactations on 138021 cows in 261 herds collected during January 2000 to December 2012 were used. The average twinning rate was 3.64% and ranged from 1.44% (primiparous) to 5.41% (multiparous). Factors as...

The objectives were to characterize repeat breeding in dairy cows, including reproductive performance and risk factors. Data from 613 Holstein Friesian cows in nine dairy herds across Japan were enrolled. A repeat breeder was defined as a cow that did not become pregnant after three inseminations, despite no clinically detectable reproductive disorders. In contrast, cows that became pregnant wi...

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...

The objective was to validate the performance under field conditions of a novel commercially available ELISA for confirmation of pregnancy using measurement of pregnancy-associated glycoproteins in milk samples from dairy cows. The target population was cows previously diagnosed pregnant by veterinary examination and ≥ 60 d of gestation. On 8 farms milking Holstein cows, milk samples were colle...

BACKGROUND Results regarding the use of bovine somatotropin for enhancing fertility in dairy cattle are variable. Here, the hypothesis was tested that a single injection of a sustained-release preparation of bovine somatotropin (bST) during the preovulatory period would improve pregnancy success of lactating dairy cows at first service. RESULTS The first experiment was conducted in a temperat...

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...