farhad kamali dehkordi

The objective of this study was to investigate the effect of vitamin A injection on reproductive performance in repeat breeder cows. One hundred and sixty-two multiparous Holstein cows with at least three consecutive unsuccessful inseminations were randomly assigned to experimental treatments. Treatments included (1) control: twice intramuscular injection 10 ml placebo30 days apart: 0.9% sodium chloride (n=87) and (2) vitamin A:  twice intramuscular injection 10 ml retinol palmitate 30 days apart (n=75). Animals submitted to double-ovsynch protocol and received their experimental treatments on the tenth day of the protocol (the day of the second injection of GnRH). The injection of retinol palmitate significantly increased the number of ovarian follicles larger than 10 mm compared to the control (P <0.05). Plasma concentration of superoxide dismutase enzyme tended to increase (P = 0.09) and malondialdehyde concentration tended to decrease (P = 0.08) under the influence of vitamin A injection. The conception rate at first artificial insemination was 25.29% and 34.66% for control and vitamin A treatments respectively, this difference was not significant (P = 0.19). The odds ratio of conception in the first service for vitamin A treatment was 1.57 times higher than the control treatment but was not statistically significant (P = 0.19). In conclusion, vitamin A injection improved antioxidant function and ovarian function. The reproductive performance improved, although not statistically significant.

The objective of this experiment was to determine the effects of fish meal supplementation on productive and reproduction performance in repeat breeder Holstein cows. Two hundred and sixty-one multiparous Holstein cows with at least three consecutive unsuccessful inseminations, without clinically detectable reproductive disorders, were randomly allocated to 1 of 3 dietary treatments. Dietary treatments were control, 2.5 or 5% fish meal, that replaced soybean meal. Cows were timed inseminated following the Double-Ovsynch protocol. Milk yield was (38.49, 39.92, and 41.42 kg/d, for cows fed the control, 2.5 and 5% FM diets respectively) of which the difference (P<0.01) between the control and 5% FM diets was significant. Likewise, 4% FCM was higher for treatment 5% FM relative to control (P<0.05). Milk fat, protein and lactose content (%) were not different among treatment (P>0.05) but milk protein yield was higher (P<0.05) for cows fed the 5% FM than control and 2.5% FM diets was significant. Plasma and milk urea nitrogen concentrations decreased significantly (P<0.05) affected fish meal by consumption. Plasma cholesterol concentration was higher for cows fed 5% FM compared to the control diet (P<0.01). Plasma progesterone concentration at 16 d post artificial insemination was greater for treatment 5% FM relative to control treatment (P<0.05). Pregnancy at the first service and cumulative (1st and 2nd service) for cows fed 5% FM content higher than control diet (P<0.05). These results indicated that supplementation the diet with 5% fish meal improved fertility and productive performance in repeat breeding cows.