Synchronisation of lambing with low doses of dexamethasone in Chios ewes — Short communication

Abstract

The purpose of the present study was to investigate the feasibility of improving the synchronisation of lambing after oestrus synchronisation and artificial insemination (AI). To this end, low doses of dexamethasone 21-isonicotinate (DEX) alone or in combination with prostaglandin F 2a (PG) were used in five treated groups (n = 20 each) and one control group (n = 136) of Chios ewes. On day 143 of pregnancy 1.5 mg DEX was given in Group 5, while on day 146 the following treatments were applied: 0.0375 mg PG in Groups 4 and 5, and 1, 1.5 and 2 mg of DEX in ewes of Groups 1, 2 and 3, respectively. The control ewes received no treatment. The 1.5 and 2 mg dose of DEX was more effective in synchronising labour as regards the treatment to lambing interval and the proportion of ewes that gave birth within 3 days. However, obstetrical manipulations were needed, and dead lambs were born when 2 mg DEX was used. It was concluded that lambing can be safely synchronised in Chios ewes with 1.5 mg DEX given on day 146, without affecting the viability of lambs and without parturition complications. Key words: Synchronisation of lambing, dexamethasone, prostaglandinsSynchronising parturitions and consequently shortening the lambing period would be of economic benefit for sheep producers (better management of newborn lambs and the pre-and postpartum ewe, eradication of maedi-visna on the basis of the artificial feeding of newborn lambs) and could improve the welfare of the stock.

Analyses of parental and seasonal influences on the synchrony of dexamethasone-induced lambing and lamb characteristics

“…The wide variation in time elapsed between induction of parturition and lambing (0.5-177 h) led us to conclude that this dexamethasone regimen was impractical for parturition synchronization of a flock of sheep. The interval from dexamethasone treatment to parturition appeared to be greater and more variable compared to that reported by Tsiligianni et al (2008) (13.0-98.3 h), who used low doses of dexamethasone (1.5-2.0 mg per ewe) to synchronize lambing in Chios ewes.…”

Two treatment protocols for induction of preterm parturition in ewes—Evaluation of the effects on lung maturation and lamb survival

“…Fylling (1971) could not induce parturition in sheep using a dose of 4 mg DEXA on day 133 of gestation. However, Tsiligianni et al (2008) were able to induce the birth process with as little as 1.5 mg of DEXA on day 146 of gestation. The authors explain this observation with the fact that this low dose was given very close to the normal due date (Tsiligianni et al, 2008).…”

“…However, Tsiligianni et al (2008) were able to induce the birth process with as little as 1.5 mg of DEXA on day 146 of gestation. The authors explain this observation with the fact that this low dose was given very close to the normal due date (Tsiligianni et al, 2008). The inducing dose of 16 mg per ewe was chosen according to the recommendations by Penning and Gibb (1977) and by Ingoldby and Jackson (2001).…”

Effect of different doses of dexamethasone on labor in Santa Inês ewes and its influence on the onset of labor and the expulsion of fetal membranes

“…In this sense, the present study also evaluated in G2 whether the administration of half the conventional dose (8mg) would have the potential to induce labor with the same efficiency. Tsiligianni et al (2008) were able to induce the birth process with just two mg and one and a half mg of dexamethasone at 146 days of gestation, which suggests that induction of labor in ewes with advanced gestation, close to the date of physiological birth, may be performed with low doses. However, the same authors observed dystocia in some births, which made it necessary to use obstetric maneuvers.…”

“…There was also the occurrence of stillbirths and placental retention in a 10% average among induced groups, which justified the use of dexamethasone. In the present study, it was used a higher dose than that reported by Tsiligianni et al (2008) in an attempt to avoid occurrences of the problems above.…”