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

Resumen

Objective: To measure the effect of zin injection, during an estrus 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.
Conclusion: 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.