Forage to concentrate ratio in Jonica breed goats: influence on lactation curve and milk composition.

The aim of the work is to evaluate the effects of different forage to concentrate rations on milk yield, composition and renneting properties of milk of Jonica breed goats. Twenty-four Jonica goats received diets with forage to concentrate ratio of 35/65, 50/50 or 65/35, providing respectively a low, medium and high energy level. Goats were divided into three homogenous groups and confined in individual pens for 152 days to assess the daily feed intake and milk yield and composition. The main conclusions show that animal body weight did not change significantly with the increasing levels of forage, whereas significant differences (P<0.05) for daily dry matter intake were observed in relation to the evolution of lactation. Milk production was influenced (P<0.05) by dietary treatments and was higher in the diet with the greatest energy level. Forage to concentrate ratios did not significantly affect milk characteristics, milk renneting properties, initial production, rate of increase until reaching the peak and rate of decline after peak production. However, the day of peak production and peak production of goats were linearly reduced when the level of forage increased within the diet. In conclusion, the results indicate that both forage to concentrate ratio and energy level improve goat's production without influencing the milk composition.