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...

Lactatingdairy cows (n=177) fed with grass and corn silage ad libitum kept in pasture, were randomly assigned to evaluate how urea nitrogen in plasma and milk can be related to their pregnancy rate. Blood and milk samples were collected on the artificial insemination (AI) day to evaluate plasma urea nitrogen (PUN) and milk urea nitrogen (MUN) as well as progesterone levels, excluding cows with ...

lactatingdairy cows (n=177) fed with grass and corn silage ad libitum kept in pasture, were randomly assigned to evaluate how urea nitrogen in plasma and milk can be related to their pregnancy rate. blood and milk samples were collected on the artificial insemination (ai) day to evaluate plasma urea nitrogen (pun) and milk urea nitrogen (mun) as well as progesterone levels, excluding cows with ...

Two experiments evaluated milk production, serum progesterone and insulin, and reproductive performance of lactating Holstein cows receiving or not receiving Ca salts of polyunsaturated fatty acids (PUFA), or receiving Ca salts of PUFA at different daily frequencies. In experiment 1, 1,125 cows randomly distributed in 10 freestall barns were enrolled. Barns were assigned randomly to receive a h...

Reproductive performance has an important effect on economic efficiency in dairy farms with short yearly periods of breeding. The individual factors affecting the outcome of an artificial insemination have been extensively researched in many univariate models. In this study, these factors are analysed in combination to create a comprehensive multivariate model of conception in Irish dairy cows....

This study was designed to determine the effects of GnRH administration alone at time artificial insemination (AI) or in combination with hCG 5 days after injection on conception rates postpartum dairy cows. Cows estrus, without any reproductive health problem, between 70-120 were randomly assigned 3 equal groups. Buserelin acetate (10 µg), administered AI Group I (n=40). II (n=40) first μg) an...

This paper discusses when to start and stop breeding cows in their lactation. First, a review of the literature on the optimal voluntary waiting period (when to start breeding cows) shows that there is not much consensus on how long the economically optimal voluntary waiting period is. Secondly, the paper then describes a computer program that calculates the insemination value (IN$) for cows in...

The dairy cows experience negative energy balance during early lactation and feeding Bypass fat in ration can produce higher milk yield, improved reproduction with better economics. An experiment was planned to evaluate of total mixed (TMR) supplemented @ 100 g/day animals for -21 120 days calving. Total sixteen were divided control group having eight each. effect on production, economics evalu...

The information about the occurrence of embryonic and fetal losses in dairy herds in Poland is limited. Thus, the objective of this study was to assess the pregnancy loss between days 30 and 45 (late embryonic mortality) and between days 45 and 260 after artificial insemination (AI) (foetal loss). The study was carried out in 8 dairy herds in north-east Poland. In total 954 cows were examined f...