Effects of starters containing different types of neutral detergent fiber on the growth performance, nutrient digestion and metabolism of Hu lambs

In this study, by adopting a controlled experimental design, we aimed to compare the differences in growth performance, nutrient digestion, and metabolism of Hu lambs, fed starters containing two types of neutral detergent fiber (NDF). As experimental subjects, we selected 28 male Hu lambs with similar birth weight (3.5 ± 0.7 kg), which had been breastfed from 0 to 2 days of age. At 3 days of age, the lambs were separated from ewes, and were fed a milk replacer until a weaning age of 28 days. At 7 days of age (prior to being fed starters), the lambs were divided into two treatment groups according to the principle of homogeneity. Each group comprised of 14 lambs, one of which was fed a total mixed ration containing alfalfa hay (AH) as the main source of NDF and the other was fed a total mixed ration containing beet pulp (BP). Digestive and metabolic tests were carried out on lambs from between 54 and 60 days of age. The feeding test was continued for 63 days. The results showed that from 7 to 28 days of age, the average daily gain, intake of nutrients, and metabolizable energy of lambs fed a starter containing AH were significantly higher than those in the BP group (P < 0.05). In contrast, from 29 to 70 days of age, there were no significant differences in these indices (P > 0.05). The apparent digestibility of dry matter (DM), NDF, and acid detergent fiber (ADF) of the lambs fed the starter containing AH were significantly lower than those of the BP group (P < 0.05). In summary, the starter containing alfalfa hay as a NDF source significantly improved the performance and intake of Hu lambs during the pre-weaning period, whereas the starter containing beet pulp as a NDF source significantly improved the apparent digestibility of DM, NDF, and ADF in Hu lambs during post-weaning.