Evaluation of melatonin and bromocryptine administration in Spanish goats

TitleEvaluation of melatonin and bromocryptine administration in Spanish goats
Publication TypeJournal Article
Year of Publication2003
AuthorsWuliji, T, Litherland, A, Goetsch, AL, Sahlu, T, Puchala, R, Dawson, LJ, Gipson, T
JournalSmall Ruminant Research
Pagination31 - 40
Date PublishedJan-07-2003

The demand for meat goats in the USA increasing particularly in Christmas - Easter holiday seasons. Manipulation for spring breeding in goats could accelerate productivity of goat flocks, enhance profitability of producers, and increase the supply of meat goats value in high demand. In this regard, four Spanish bucks were conditioned for 2 months to long-day photoperiod (16-hour light: 8-hour dark), followed by a single melatonin implant (18 mg, 6-week release period). Eighty Spanish does were allotted to five treatments: control (C); melatonin implant (MI); melatonin and bromocryptine (225 mg, 60-day release period) implants (MIB); oral administration of melatonin (MO, 3 mg/day); and oral administration of melatonin and bromocryptine implant (MOB). After the fifth week of melatonin administration, does were randomized and bred in three single-sire groups for two estrus cycles. The artificial long day light conditioning and melatonin supplementation for bucks stimulated breeding behavior, libido, buck effect, and fertility during spring mating. Melatonin treatment and the buck effect induced out of season breeding in anoestrus does. Although there were not a large number of variables with significant treatment effects, these results suggest that melatonin implanted or orally administered daily would be necessary to achieve a high percentage of does bred and a large number of fall born kids. Furthermore, these findings imply that an accelerated out of season breeding system with goats, scheduling kidding twice both in the fall and spring is feasible. Such a system should increase total annual meat goat production as well as increasing meat goats available during the Christmas-Easter holiday season when prices are generally elevated. However, for rapid growth of fall born kids, it may be necessary to utilize high quality forages productive in the fall-winter period, such as cool season annuals. Out of season breeding also offer potential to decrease age of first breeding and concomitantly improve lifetime reproductive efficiency.

Short TitleSmall Ruminant Research