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Abstract
Objective: To evaluate the effect of bypass fat during the postpartum period in Pelibuey ewes synchronized with an intravaginal progesterone-releasing device (CIDR).
Design/methodology/approach: Seventy-six Pelibuey sheep suckling were used during the postpartum period, with an average body condition score of 3. The ewes were randomly assigned to one of four treatments: T1 = cs (continuous suckling; n = 19), T2 = CS (controlled suckling; n = 19), T3 = cs + bypass fat (ac + FAT; n = 19), and T4 = CS + bypass fat (AC + FAT; n = 19). The experimental design was completely randomized with a 2 x 2 factorial arrangement. There were two factors: factor A was suckling, with two respective levels: 1, continuous (c); 2, controlled (C); while factor B was bypass fat supplementation, grouped into two levels: 1, no bypass fat in the diet; 2, bypass fat in the diet. The SAS statistical package (2009) was used for data analysis, performing logistic regression tests (PROC LOGISTIC), Poisson distribution (PROC GENMOD), and survival analysis (PROC LIFEREG) according to each variable.
Results: bypass fat and type of lactation had no effect on the variables of estrus manifestation, time to estrus, return to estrus, pregnancy rate, and birth rate (p >0.05). However, statistical differences (p<0.05) were found in the variables of embryonic loss (p=0.0005), prolificacy (p=0.04), and fertility (p=0.03).
Limitations on study/implications: The results were obtained with a limited number of sheep in each of the treatments.
Findings/conclusions: The interaction of controlled lactation and supplementation with bypass fat is an efficient and cost-effective management strategy that improves reproductive efficiency during the postpartum period by reducing the interval between calving and first ovulation.