Effect of grain source (corn or barley) and the ratio of rumen undegradable protein to rumen degradable protein on performance, skeletal growth indices and blood metabolites of Holstein calves
2020
Basereh, K. | Fattahnia, F. | Kazemi-Bonchenari, M. | Ahmadian, A.
The present study evaluated the interaction of grain source (corn vs. barley) and ruminal undegradable protein: ruminal degradable protein ratios (RUP: RDP; 27:73 and 36:64) on growth performance and blood metabolites of Holstein calves. Forty three-day-old male calves with a body weight of 42.6 ? 2.9 kg were used in a completely randomized design with a 2 ? 2 factorial arrangement of treatments. Treatments were: (1) corn grain with low RUP: RDP; (2) corn grain with high RUP: RDP; (3) barley grain with low RUP: RDP; (4) barley grain with high RUP: RDP. Calves were weaned on d 53 of age but remained in the study until d 63. The results showed that starter intake was similar among treatments. The average daily gain and feed efficiency were improved in calves fed barley grain (p < /em> = 0.04). Wither height was improved in high RUP: RDP fed calves. Hip height was improved in barely fed calves (p < /em> = 0.06). Blood concentration of beta hydroxyl butyric acid was 0.33 mmol and greater in barley fed calves (p < /em> = 0.02). The total protein level was greater in calves fed higher RUP: RDP. Barley fed calves had lower blood concentration of blood urea nitrogen (p < /em> = 0.01). The blood insulin concentration was increased in barley fed calves along with increase in RUP: RDP (p < /em> = 0.02). In conclusion, results indicated that feeding starter contained barley grain and high ratio RUP: RDP and also starter contained corn grain with low RUP: RDP is recommendable for starter diet of dairy calves.
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