G. STAYKOVA, P. PENCHEV and N. STANCHEVA
Agricultural institute – Shumen, 3 Simeon Veliki Blvd., Shumen 9700, Bulgaria
STAYKOVA, G., P. PENCHEV and N. STANCHEVA, 2013. Interrelationship between body condition score at different physiological statuses and some economic traits in the Caucasian sheep breed. Bulg. J. Agric. Sci., 19: 1105-1111
Subject of the study were 241 primiparous Caucasian Merino ewes born in 2009 and bred on the state farm “Kabiuk”. In correspondence to the physiological status, three sessions of body condition score (BCS) assessment were accomplished using the five-rank system: during first lactation month, prior to artificial insemination, and during first gestation half. It was established that BCS was affected significantly by physiological status (P<0.001), the average estimates being higher in early pregnancy (2.89) and before insemination (2.75) compared to post-partum period (2.37), all three just within lower recommended limit for adult ewes. BCS constitutes relatively low portion of the variation of live weight, expressed in directly proportional change of up to 4 kg per BCS-unit (P≤0.001) and in phenotypic correlations ranging from rP = 0.446 to rP = 0.523 (P≤0.001). Wool yield in first lactation month is significantly improved by 550 g with each unit increase in BCS (P≤0.01, P≤0.001), the correlation coefficient being rP = 0.371 (P≤0.001). In terms of biological prolificacy, the ewes with BCS of 2.5 to 3.5 tend to be in most optimal breeding condition before the insemination campaign (P>0.05), while conception rates are highest in those with low BCS. Most obese body condition during pregnancy is associated with lowest incidence of abortions and still-births.