Relationship between the number of lactation and milk yield on Saanen goat farms

Abstract

The authors examined the milk production, on five Saanen-goat farms at the time of the monthly milkrecordings. In their present study they endeavoured to examine the connection between lactation number and milk production. They tried to find out how the increase in the lactation number of the mother goats affect the milk yield; in which lactation these values are the highest and until which lactation it is worth keeping the mothers in production. There were 37 ewes on farm No. 1, 17 on farm No. 2, 45 on farm No. 3, 17 on farm No. 4 and 80-90 on farm No. 5. On farm No 1-4 the daily milk yield was measured five times a month from May to September. On farm No. 5 the examinations were continued for three years. The data were processed by Microsoft Excel 5.1 and analysed by SPSS for Windows 15.0 programmes. To determine the relationship between the data univariate variance analysis and Pearson' correlations were applied. The highest milk yield was observed in lactation 3 and 4. The most milk was produced by the does on farm 5 in lactation 4 (2.75 milk kg/day/doe; r = 0.31; P < 0.01), while the least yield was given by the ewes on farm 4 (lactation 7; 0.52 milk kg/day/doe). Based on the evaluation in the end the peak of the mild yield was in lactation 4. (2.46 milk kg/day/doe; r = 0.16; P < 0.01), and in lactation 7 the milk yield of the ewes was the same as that of the ewes in lactation 1. Based on these findings it was concluded that the mothers could be kept in production until their 7th - 8th lactation. When considering milk yield a value of h2 = 0.22 (P<0.05) was found in the given stock, which means the heritability of this parameter indicated a poor heritability, according to their results. The farm effect proved to be significant in case of the milk yield.