Two protocols to synchronize the oestrus of lactating ewes using progestogens

Molina S.E.; Rojas G.E.; Huaroco C.T.; Huayta M.C.; Guerra U.H.P.; Cruz D.J. · Revista de Investigaciones Veterinarias del Peru (2022) · DOI: 10.15381/rivep.v33i6.24095

Resumen

The aim of this study was to evaluate two protocols for oestrus synchronization using intravaginal progestogens. In the study, 64 ewes with lambs at foot of 30-40 days old were used. The animals were assigned to two groups: (T1): application of a short synchronization protocol (6 days) with suppression of suckling for 30 hours (n1=32) and (T2): application of a long or conventional protocol (12 days) with suppression of suckling for 54 hours (n2=32). Fixed-time artificial insemination (FTAI) was performed with refrigerated semen through the transcervical route at the end of temporary weaning. The pregnancy rate without heat return at 16-17 days post-FTAI, pregnancy rate at 41 days by ultrasound, pregnancy rate at 90 days by balloting and type of delivery were determined. The rate of non-return to oestrus at 15-17 days post-FTAI was 81.25% for T1 and 87.50% for T2 (p<0.05). Likewise, the pregnancy percentages by ultrasound and by balloting were statistically similar between treatments. The twin birth rate was slightly, but not significantly different in T2 (26.92%) than in T1 (19.2%). The results show that when applying a short synchronization protocol, similar results are achieved as when applying the conventional synchronization protocol and with the advantage that it is carried out in less time.

Instituciones: Universidad Nacional del Altiplano; Universidad Peruana Los Andes; Universidad Nacional del Centro del Perú