Determination of lactation curve and factors affecting laktation curve parameters of Awassi ewes in Ceylanpınar State Farm

83 7. SUMMARY Determination of Lactation Curve and Factors Affecting Lactation Curve Parameters of Awassi Ewes in Ceylanpinar State Farm In this study was determined the lactation milk yield, lactation duration, lactation curve parameters and lactation persistency of Awassi sheep in Ceylanpinar State Farm. The milk yield records kept between 1993-1995 for milk yield characteristics and the yield records kept between 1992-1995 for lactation curves were used. As related to the lactation curve, the shape of the lactation curve, lactation curve parameters (A, B, C), persistency of lactation (S), daily yield at the time of peak lactation (Ymax) and the time of peak lactation (Tmax) were determined. In determination of the effects of the lambing season, lambing year and ewe age on the lactation curve characteristics and milk yield was used the Least Squares Estimation Method The significance of the results was determined by variance analysis. The effect of lambing season was found as significant while determined as non-significant the effect on milk yield of ewe age and lambing year. The effect of lambing season and lambing year were found to be significant (P<0.01) on lactation duration but effect of the ewe age was found non-significant. The averages of lactation milk yield and lactation duration were found to be 176.61 ±0.93 kg and 204.12±1.73 day, respectively. Lactation curves and shapes were estimated by the parameters of Gamma Functions (Yt = At& e-ct). The 2.0 % of lactation curves were atypical which was 79 % concave (B, C negative) and 21 % down-hill (B negative). The84 distribution of typical and atypical lactation curves found to be independent upon the lambing season, lambing year and ewe age. The determination coefficient (r2) for lactation curves of gamma function was found between 59.14 - 84.64. The effect of lambing season on B, C values were non-significant (P<0.01) whereas effect of A value was found to be significant (P<0.01), on the other hand, the effect of ewe age was non significant on A, B, C parameters. The effect of lambing season and lambing year on S value were significant (PO.01) whereas the effect of ewe age was found to be insignificant. The average of Ymax was determined as 1575±29.08 g. The effect of lambing season and lambing year on Ymax value were found to be significant statistically (P<0.01) but, the effect of ewe age was been as non-significant. The average of Tmax was found 55.30+0.94 days. The effect of lambing season on Tmax value was found to be non-significant. But, ewe age and lactation year were been to be significant (PO.01). Correlations between persistency with A parameters and Ymax value (respectively -0.53 and -0.81) were determined negatively and significantly. Correlation between A parameter with Ymax and Tmax values (respectively 0.95 and 0.22) were found significantly and positively. Correlations between lactation duration with Ymax value and lactation milk production (respectively, 0.19 and 0.22) were found significantly and positively. Correlations between lactation duration with Ymax value and lactation milk production (respectively, 0.019 and 0.54) were determined significantly and positively.