2024 : 12 : 4
Mehdi Mirzaei

Mehdi Mirzaei

Academic rank: Assistant Professor
ORCID: https://orcid.org/0000-0002-1445-2986
Education: PhD.
ScopusId: 57004439300
HIndex:
Faculty: Agriculture and Environment
Address: Arak University
Phone:

Research

Title
Effects of low‑quality forage and starter protein content in starter diet of young calves on growth performance, rumen fermentation, and urinary purine derivatives
Type
JournalPaper
Keywords
Low-quality forage · Heat stress · Young calf · Rumen development
Year
2024
Journal Tropical Animal Health and Production
DOI
Researchers Reza Jalayernejad ، Mehdi Kazemi bonchenari ، Mehdi Mirzaei ، Mehdi Hossein Yazdi

Abstract

Feeding low-quality forage (LQF) has been evaluated in mature ruminants and results show that it has been improved nitrogen utilization efficiency. The present study evaluated the interaction effect of feeding wheat straw as LQF (0 and 7.5%, DM basis) and starter protein level (20 vs. 24%, DM basis) on growth performance, ruminal fermentation, and microbial protein synthesis in Holstein dairy calves raised under moderate heat stress condition. Forty-eight 3-day old dairy calves (averaging 40.6 kg) were assigned in four experimental treatments as follow; 1) no LQF with 20% CP (NLQF-20CP), 2) no LQF with 24% CP (NLQF-24CP), 3) 7.5% LQF with 20% CP (LQF-20CP) and 4) 7.5% LQF and 24% CP (LQF-24CP). The calves were weaned on d 53 of age but the experiment extended until d 73 of age. Feeding LQF increased starter intake, average daily gain (tendency), ruminal acetate concentration, and improved fecal score of calves. The average daily gains before and after weaning were positively influenced with greater starter protein content. Hence, weaning and final BWs were improved when calves received greater CP content. In addition, greater starter CP content increased total ruminal volatile fatty acid concentration. With respect to the interaction effect between LQF feeding and starter protein content, the lower nitrogen excretion through urine was obtained for LQF-20CP diet among experimental treatments. The results of the current study showed that feeding LQF improved ruminal fermentation pattern and improved growth performance through increased starter intake. In addition, greater starter protein content is advisable during pre-weaning period for calves raised under mild heat stress condition. In conclusion, based on the results found in the current study, it can be suggested that feeding LQF for calves under heat stress condition can improve nitrogen utilization when dietary protein content is low. This can be opportunity to formulate starter diets with greater nitrogen utilization efficiency which is critical for accelerated growth programs at early stages of growth for young calves while calves raised under hot season condition.