Milk yield and composition in Swedish landrace goats (Capra hircus) kept together with their kids in two different systems

Abstract: Swedish goats are mainly held for cheese production and therefore, both milk quality and composition are of great importance for dairymen. Today, only few data exists on milk composition from Swedish dairy goats and the casein content is still unknown. One way to reduce the work load for goat farmers and increase animal welfare can be to keep goats and kids together for longer periods. The aims of this study were to investigate how milk yield and composition were affected when kids suckled their dams during 8 weeks, and to measure the casein content on farm level by a mid-infrared spectroscopy method, previously calibrated for goat milk. Lactating goats were kept in two different MIX- systems where the dams are both suckled and milked. All goats were machine milked twice daily. Group 1 (n=5) was kept together with one kid for 16 hours a day (T-16h), kids and dams were separated daytime between 7:30 and 15:00, kids were allowed to suckle before each milking. In group 2 (n=6) the dam and kid were kept together for 24 hours but the kid was only allowed to suckle one teat as the other teat was covered with a bra. The daily milk yield was higher in T-16h goats (P<0.05) compared with T-24h goats; 2.5 ± 0.8 and 2.1 ± 0.6 kg, respectively. The fat content was higher in T-16h 4.9 ± 0.9% than in T-24h goats; 4.4 ± 0.7% (P< 0.001). The protein and lactose content were 3.2 ± 0.4% and 4.8 ± 0.4% in T-16h goats and 3.1 ± 0.3 and 4.7 ± 0.3% in T-24 goats. The daily casein number (% of total protein) was 72 ± 5% in both groups. The results indicate that it is possible to maintain milk yield with one kid present. Suckling also increases the fat content if the kid is allowed to suckle before each milking. This study shows that the milk composition is positively affected by keeping goats and kids together, and that it is possible to measure the casein content in goat milk by a mid-infrared spectroscopy method on-farm.