[Effects of rumen-protected conjugated linoleic acid supplementation on production responses, milk composition and blood metabolites in holstein dairy cows]

Rumen-protected conjugated linoleic acid [CLA] may increase the protein to fat ratio in milk, and potentially improve the energy balance of early lactation cows. The objective of this study was to evaluate the production performance and blood metabolite changes in Holstein cows supplemented with four different doses of CLA postpartum in early lactation. Eight multiparous Holstein cows with at least 25 kg/day milk production were randomly chosen and were included in an experimental design with four three week periods [7 days of adaptation and 14 days of treatment and sampling]. The experiment was carried out with four levels of protected CLA supplement including 0, 50, 100, and 150 g per day per cow. Blood metabolites such as cholesterol and LDL-C content decreased significantly [p<0.05], but other metabolites such as HDL-C, VLDL-C, triglyceride and BHBA did not change [p>0.05]. Milk production increased significantly [p<0.05], and 100 g/day of CLA supplemented treatment resulted in the highest production compared with the other groups. Milk fat percentage of the treated cows was reduced significantly and followed a dose-dependent response. No significant results were observed with regard to the protein content, solids-non-fat and milk density of the milk [p>0.05]. The increased milk production, and decreased blood LDL-C and cholesterol levels indicate an improvement in the physiological state of the cows. Given the enrichment of produced milk using this supplement, it is highly recommended to provide these supplements in dairy cow diets

[Comparison of voluntary intake, digestibility of nutrients of the ewe milk and a commercial milk replacer and their effects on performance in dalagh breed suckling lambs]

Early weanling and rearing of lambs on milk replacer is an important act to increasing flock productivity. Two experiments were carried out to compare the voluntary intake and nutrients digestibility ewe milk and commercial milk replacer and their feeding effects on the growth rate, feed intake and feed efficiency of suckling lambs. In experiment 1, eight lambs [two 4-lamb groups] at 31 to 34 days of age for 14 days and in experiment 2, thirty [two 15-lamb groups] Dalagh breed male lambs at 3 +/- 1 days of age for 90 days were reared in individual cages. In both the experiments, one group was fed with ewe milk and the other one with milk replacer. In experiment 1, the average of dry matter intake per Kg metabolic weight, dry matter, crude protein and crude fat digestibility of lambs which were fed with those which were fed with ewe milk and milk replacer had statistically significant difference [p< 0.01]. In experiment 2, the average of daily weight gain, dry matter intake and feed efficiency of lambs fed with ewe milk and milk replacer did not have statistically significant differences [p>0.05]. These experiments showed that suckling lambs fed with milk replacer in comparison with those fed with ewe milk; did not have any difference in growth, feed intake and feed efficiency