Culture of bovine embryos in the presence of insulin-like growth factor-1 (IGF-1) can increase pregnancy rates following transfer to heat-stressed, lactating dairy cows. The objective of the present experiment was to determine whether the effect of IGF-1 on post-transfer embryo survival was a general effect or one specific to heat stress. Lactating recipients (n=311) were synchronized for timed...

The decision of when to calve beef females is critical to production efficiency and profitability in a cow and calf enterprise. Calf production and associated costs are affected by calving season because environmental conditions, stage of production, and season of the year interact to affect nutritional status and reproductive performance. Cow and calf producers typically choose to commence cal...

calving records of iranian buffaloes from april 1991 to june 2010 comprising 1,151 herds with 34,911 calving events were used to evaluate reported secondary sex ratio, stillbirth, and calf birth weight. logistic regression models were applied to analyze stillbirth and calf sex at birth, and statistical analysis of calf birth weight was performed using a linear mixed model. overall, the ratio of...

The objective of the present study was to estimate genetic trends for lactation milk yield, persistency of milk yield, somatic cell count and interval between first and second calving in Holstein dairy cows of Iran. The dataset consisted of 210,625 test day and 25,883 first parity cows with milk yield recorded from July 2002 to September 2007 comprising 97 herds in Iran. Breeding values of anim...

Accepted: 02/06/2014 Abstract Several physiological changes occur in the cow’s uterus soon after calving. These changes are significant if a cow is to recover and come back into season, ready to conceive, thus any factors that interfare with the normal functioning of the uterus and other associated structures will affect overall reproductive performance. Research has shown variations in the pre...

Records on 3092 pregnancies distributed over a period of 24 years (1986 to 2010) were used to estimate genetic and non genetic parameters of threshold traits in Holstein Friesian. Parity, season and year of calving were included in the model to estimate their effect on replacement traits. A total of 105 sires' records were used to study the genetic component of the characters. The overall avera...

A 3-yr study was conducted to evaluate the effects of calving system, weaning age, and postweaning management on growth and reproduction in beef heifers. Heifer calves (n = 676) born in late winter (average birth date = February 7 +/- 9 d) or early spring (average birth date April 3 +/- 10 d) were weaned at 190 or 240 d of age, and heifers born in late spring (average birth date May 29 +/- 10 d...

Two experiments evaluated prebreeding target BW or progestin exposure for heifers developed lighter than traditional recommendations. Experiment 1 evaluated the effects of the system on heifer performance through subsequent calving and rebreeding over 3 yr. Heifers (229 kg) were assigned randomly to be developed to 55% of mature BW (299 kg) before a 45-d breeding season (intensive, INT; n = 119...

AIM This study was carried out to investigate the genetic analysis of reproductive performance of Frieswal cattle at Military Farm, Ambala. MATERIALS AND METHODS A total number of 3005 lactation records of 1147 Frieswal cows over a period of 15 years extending from 1993 to 2007 were used to study at Military Dairy Farm, Ambala. The study period was divided into 5 period of 3 years each. The a...