Influence of lactation order and live weight on milk yield and fertility traits in domestic Balkan goat

Abstract

The goal of investigation in the domestic Balkan goat was to establish the effect of body weight and lactation number on milk yield and fertility. Research was done in herds belonging to private farmers, during a one-year period, on a total of 578 goats. Investigated herds were monitored also by lactation number, i.e. kidding number (lactations 1,2 and 3 individually, lactation 4 and following lactations investigated together). Body weight and milk yield were measured, while fertility was determined as the number of live born kids per 100 goats. Goats were also sorted into groups by age and body weight, while the interval within groups and between groups was 5 kg. Average total milk yield in the investigated population of the domestic Balkan goat was 177.5 kg. A statististically significant difference (P<0,01) was established for milk yield depending on body weight and age, except for goats in lactation 1 (P<0,05). In lactation 3 and 4, goats with body weights over 45 kg, comprising 30.23% of the total number in these groups, had the highest milk yields (over 200 kg). Pertaining to lactation number, i.e. kidding number, as well as body weight in both years of investigation, lowest fertility was found in lactations 1 and 2 (112%), and in goats with lowest body weight (25-30 kg), while this considerably increased lactation 4 and later lactations (136%), and body weights of over 40 kg (140%).