EFFECT OF MOBILIZATION OF BODY RESERVES ON OVARIAN REACTION OF COWS SUBJECT TO SUPEROVULATION TREATMENT

The aim of this work is to highlight the influence of variations of some energy balance indicators on the ovarian reaction to superovulation treatment. A three day superovulation protocol was implemented in five cows. Glycemia, BHB (β-hydroxybutyrate), NEFA (non-esterified fatty acids) and body condition score (BCS) were monitored before and during treatment. The ovarian reaction was assessed by estimating the number of corpora lutea. All biochemical parameters underwent variations at one time or another during the protocol. Maximum concentrations of 2.2 mmol/l, 1.01 g/l, 1.36 mmol/l were recorded respectively for BHB, glycemia and NEFA. Despite the lack of correlation between these parameters and the number of corpora lutea, the assays demonstrated a mobilization of body reserves in all the cows which caused a negative energy balance. Our results show that the parameters studied can support clinical data in the selection of embryo donor cows and serve as a discriminatory factor for those with a negative energy balance

CORPUS LUTEUM SIZE AND PLASMA PROGESTERONE CONCENTRATION DURING THE ESTROUS CYCLE IN CHEURFA COW OF ALGERIA

The aim of this study was to assess the relationships between the evolution of the corpus luteum size determined by ultrasonography and plasma progesterone concentration in Cheurfa cows during the estrous cycle. Luteal activity was evaluated daily by plasma progesterone concentrations determined by radioimmunassay at each ultrasound examination. The interovulatory interval was 20.5±0.6 days. The corpus luteum clearly delimited 2 days after ovulation reached its maximal size on day 10. The plasma progesterone concentration reached its maximum on days 14. There was a day effect of estrous cycle on corpus luteum size (P<0.0001) and plasma progesterone concentration (P<0.0001). During the growing and regression phases of corpus luteum, a significant correlation was found between plasma progesterone concentration and corpus luteum size. In conclusion, the relationships between the corpus luteum size and plasma progesterone concentrations throughout the estrous cycle in Cheurfa cow were similar to other cattle breeds

Effect of the Reduction in the Frequency of Injections of Pituitary Extracts During a Superovulation on the Embryo Collection Results in Cows in Algeria

The aim of this study is to verify the efficacy of a superovulation treatment with 3 injections of pituitary extracts (Stimufol®) 24 hours apart and compare the results to a standard protocol (8 injections 12 hours apart), with a total dose of 500 μg. Twenty-three embryos collections were conducted after two superovulation protocols, the first with 8 injections 12 hours apart and decreasing doses (n = 11, group 1) and the second 3 injections at constant doses 24 hours of interval (n = 12, group 2). The average number of lutea corpora obtained is 9.1 per cow for group 1 and 10.4 in group 2. A total number of 140 embryos were collected with an average of 6.08 per cow. Among the embryos collected, 46 and 56 per cent were transferable respectively in group 1 and 2. A little quality gain was recorded in group 2 with an average transferable embryo of 3.8 against 2.2 for group1. In our study we observed the same efficacy for both treatments with a little quality improvement (almost one transferable embryo) when reducing the number of injections at the time of superovulation treatment, the same gain minimal in elite cows can have a significant economic impact