Effects of a sustained-release multi-trace element ruminal bolus on sex ratio, reproductive traits and lambs growth in synchronized Afshari ewes

Effects of a sustained-release multi-trace element ruminal bolus on sex ratio, reproductive traits and lambs growth in synchronized Afshari ewes

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The objective of the present study was to investigate the effects of a sustained-release multi-trace element ruminal bolus on sex ratio, the reproductive performance and lambs growth of Afshari ewes.Eighty Afshari cycling ewes during ah6789-001 breeding season were used in the trial.The animals were synchronized using CIDR for 14 days and assigned into 4 groups including: group 1 (n=20) received a single Ferrobloc bolus four weeks prior to CIDR insertion following 400 IU eCG on CIDR removal, group 2 (n=20) received two boluses four weeks prior to CIDR insertion following 400 IU eCG on CIDR removal, group 3 (n=20) received only 400 IU eCG on CIDR removal and group 4 (n=20; control) received no bolus and no eCG.Growth traits were analyzed using the mixed procedure of SAS.

Number of observations (lambing rate, litter size, barren rate and the male / female lamb rate) in different groups was compared using the Chi-Square test.Results showed that ruminal bolus can play an indirect role in skewing sex ratio toward male offsprings.Given 1 or 2 sustained-release essie day drift away multi-trace element ruminal boluses four weeks before synchronization programme using eCG, causes the pregnancy of all ewes.Of the four treatments tested, the 2 boluses+eCG showed superiority on reproductive performancein terms of lambing rate (150%) and litter size (150%) in Iranian Afshari ewes during breeding season.

Also, bolus supplementation enhances lamb body weight at birth up to 60 days of age.