Pregnancy rate in ewes injected with zinc oxide during a synchronization protocol Fertility in ewes injected with zinc oxide during a synchronization protocol

Abstract

Objective: to measure the effect of zin injection, during a synchronization protocol, on pregnancy rate in sheep from the “Valle de Mexicali”. Design/methodology/approach: the experimental units were 157 ewes, which were allocated in five farms (UP): UP1 (n=19), UP2 (n=27) UP3 (n=20) UP4 (n=71) and UP5 (n=21). In each farm, the ewes were randomly assigned to one of three treatments: control, z-100 and z-200. The ewes from control groups were subcutaneously injected with 4 mL of olive oil as placebo. The ewes from groups z-100 and z-200 were subcutaneously injected with 100 and 200 mg of zinc oxide. The response variables were the preovulatory diameter of the largest follicle and pregnancy rate. Results: the differences between experimental groups on diameter of the largest preovulatory follicle and pregnancy rates were not significant different (p>0.05). Limitations of the study/implications: the ewe’s reproductive response to zinc injection might be affected by the animal mineral status, it is recommended to carry on supplementation with base on mineral blood concentrations. Conslusion: the subcutaneous injection with 100 or 200 mg of zinc oxide did not affect the size of the largest preovulatory follicle and pregnancy rate in ewes.

Key words: minerals, reproduction, sheep