Influencia de la grasa bypass sobre el reinicio de la ciclicidad de las vacas lecheras de la parroquia Victoria del Portete

Abstract

The aim of this study was to evaluate the effect of the addition of bypass fat as an energy supplement in ovarian activity and return to the cyclicality of dairy cows of Victoria del Portete. 60 Holstein cows and their crosses, 2 to 5 calving were used with body condition at calving of 3.0 to 3.5; Free of reproductive diseases under grazing system and mechanical milking; They were distributed in 4 treatments (15 animals per treatment) supplemented with bypass fat based on the estimated DMI: A 3% treatment (475-538gr); Treatment B 2% (296-361gr); C treatment 1% (154-175gr) and treatment D 0% (0gr). They were evaluated every 10 days by ultrasonography: presence of corpora lutea, follicles, follicular size, number of days to first postpartum estrus up to 60 days, CC was recorded from birth to 60 days. ANOVA followed by Tukey significance tests. Follicles (C>B≥D≥A): significant differences between treatment C and other treatments for the presence of ovarian structures were found. Likewise statistical difference was observed in the period of days to first postpartum estrus (B≤C<D≤A) and body condition (A=B=C>D). There was no significant differences in the number and size of follicles (A=B=C=D), or conception rate. It is concluded that the addition of bypass fat improves body condition and reduces the time interval to first postpartum estrus but does not improve the number and size of follicles, does not improve pregnancy rates at the first postpartum insemination