Goats' Milk Production and Kids' Growth: Effects of Supplementation Type Under Forest Pasture System

The objective of this study was to evaluate the effect of concentrate type on goat’s milk yield and quality under forest grazing conditions as well as on their kids’ growth performances during pre-weaning. The experiment was conducted in the Ain Drahem region using a total of 26 local breed goats, divided into two groups, each managed by a breeder. Within each farm, the goats were divided into three homogeneous sub-groups based on their milk production levels. The first diet: farmer’s feed (FF) represented the control and the traditional diet combining forest grazing with occasional supplementation of fresh forage (barley, oats, and triticale). The second diet (CC) composed by forest grazing and a conventional concentrate consisting of 80% barley, 17.5% soybean meal, and 2.5% mineral-vitamin mixture. The third diet: rosemary concentrate (RC) included forest grazing and a concentrate incorporating distilled rosemary leaves (DRL) (73.5% DRL, 22.5% wheat bran, and 4% soybean meal). Each goat received 400 g of concentrate daily. During the trial, the goats had free access to water throughout the day. Goats ‘milk yield and composition, and kids’ growth parameters were recorded. The milk yield was affected neither by the diet nor by the breeder; the average milk production was 352, 293, and 338 ml for FF, CC, and RC groups, respectively. The protein content remained unchanged among groups (3.8, 3.6, and 3.5% for FF, CC, and RC, respectively; P > 0.05). Similarly, the fat content did not vary with DRL inclusion (4, 4, and 3.8% for FF, CC, and RC, respectively; P > 0.05) nor with the breeder. Despite a lower initial body weight (7 kg), kids in the RC group reached a final body weight comparable to those in the other groups. This was supported by similar average daily weight gain values (86 g/day; P > 0.05). It could be concluded that DRL incorporation in concentrate resulted in comparable milk production and kids’ growth, highlighting the potential of substituting barley with DRL in goat feeding strategies without altering the animals’ performances.