پژوهشهای تولیدات دامی (Dec 2023)
Effect of Milk Replacer Plane of Nutrition on Intake, Weight Gain, and Skeletal Growth in Cold-Stressed Newborn Holstein Calves
Abstract
Extended Abstract Introduction and objectives: The lower limit of critical temperature for a newborn calves is between 5 (from 3 weeks and later) to 15°C (up to 3 weeks). As the temperature declines below the calf's lower critical temperature, a calf requires more dietary energy supply to maintain body temperature. Hence, the main goal of this trial was to investigate milk replacer feeding level on nutrient intake, weight gain and skeletal growth in newborn Holstein calves under cold stress. Material and Methods: The number of twenty-four neonatal Holstein calves were randomly assigned to receive either restricted (4 L/d; RPN) or moderated (6 L/d; MPN) milk replacer plane of nutrition. Calves were weaned on d 61 and remained in the study until d 91. Milk replacer intake, starter feed intake, and ambient temperature were measured daily. Body weight was measured immediately before initiation of study and every 10 d thereafter. The average daily gain (g of BW gain/d) was computed as the difference between BW recorded at 10-d intervals divided by 10. Body frame size was measured immediately before initiation of study, at weaning, and at the end of the trial. Results: Nutrient intake originating from milk replacer were greater in MPN fed calves before weaning (P < 0.001); however, nutrient intake originating from starter feed and also total nutrient intake (except for crude fat and ME) were not affected by treatment groups before and after weaning. Average daily gain was greater in MPN fed calves (P = 0.04). Body weight gain before and after weaning and over the study period was greater in MPN (P = 0.01). Withers height (at the end of trial), body barrel (at weaning and at the end of trial), hip height (before weaning and overall period), and hip width (after weaning and overall period) gained more in MPN fed calves (P ≤ 0.05). Conclusion: Changing the feeding level of milk replacer did not affect starter feed intake before and after weaning but calves fed with medium level of milk replacer hand more weight and skeletal growth. In general, feeding a moderated level of milk replacer is recommended in newborn Holstein calves under cold stress conditions.
