1- PhD student in Department of Animal Sciences, University of Sari Agricultural Sciences and Natural Resources, Sari, Iran
2- Faculty member of Department of Animal Sciences, University of Sari Agricultural Sciences and Natural Resources, Sari, Iran
3- Animal Science Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, AREEO, Isfahan
2- Faculty member of Department of Animal Sciences, University of Sari Agricultural Sciences and Natural Resources, Sari, Iran
3- Animal Science Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, AREEO, Isfahan
Abstract: (57 Views)
Background and objective: The importance of calf breeding in the economic sustainability of dairy herds is clear. Apart from the milk feeding program, the physical form of the starter feed as well as the forage intake are effective factors in the growth of dairy calves. So far, no research has investigated the interaction effect of the physical form of the starter feed and the inclusion time of forage on the digestibility, rumen and blood parameters of Holstein dairy calves. The purpose of this experiment is to investigate the effect of forage inclusion time and the physical form of the starter feed on digestibility, rumen and blood parameters of Holstein dairy calves.
Materials and methods: This experiment was conducted in the form of a completely randomized design and with a 2 x 2 factorial method and for 85 days. For this purpose, 40 calves were used and the calves were divided between 4 experimental treatments (each treatment included 10 calves). Experimental diets include 1- ground starter feed with forage (10% alfalfa hay) from the first day of the experiment 2- ground starter feed with forage from the 21st day of the experiment 3- pelleted starter feed with forage from the first day of the experiment 4- pelleted starter feed with forage from the 21st day of the experiment. Statistical analyzes were performed using the MIXED method by SAS software with the effect of time as repeated measurements.
Results: Feeding forage from day one of age compared to day 21 of age (P=0.078) and pellet compared to ground diet (P=0.064) tended to increase protein digestibility throughout the period. On the other hand, feeding pellet compared to ground starter increased fat digestibility throughout the period (P=0.033). Feeding forage from one day of age compared to 21 days of age increased the digestibility of neutral and acid detergent insoluble fiber. Also, feeding pellet diet increased the digestibility of neutral and acid detergent insoluble fiber compared to ground. Also, feeding forage from one day of age compared to 21 days of age increased pH and cellulase activity and decreased rumen ammonia nitrogen. Also, cellulase activity was higher in pellet-fed groups than in ground-fed groups. An interaction between feed texture × time of forage initiation was observed, such that feeding pelleted feed with forage from 1 day of age had the highest cellulase activity, pH, and the lowest ammonia nitrogen. Feeding forage from 1 day of age compared to 21 days of age increased rumen acetate concentration. Also, calves consuming pelleted feed tended to have higher acetate concentration as well as higher levels of propionate and butyrate and total rumen fatty acids compared to ground feed. On the other hand, ground feed increased serum glucose concentration compared to pelleted feed, and forage consumption from 1 day of age led to a decrease in serum glucose and β-hydroxybutyrate levels.
Conclusion: Alfalfa intake at 10% at 1 day of age compared to 21 days of age resulted in increased rumen fiber digestibility, which is due to increased rumen health and higher rumen cellulase activity. Also, feeding pelleted compared to ground diets resulted in increased rumen fatty acid production. The interaction between feed texture and time of forage initiation showed that the use of forage at 1 day of age in calves consuming pelleted diets resulted in increased rumen function.
Materials and methods: This experiment was conducted in the form of a completely randomized design and with a 2 x 2 factorial method and for 85 days. For this purpose, 40 calves were used and the calves were divided between 4 experimental treatments (each treatment included 10 calves). Experimental diets include 1- ground starter feed with forage (10% alfalfa hay) from the first day of the experiment 2- ground starter feed with forage from the 21st day of the experiment 3- pelleted starter feed with forage from the first day of the experiment 4- pelleted starter feed with forage from the 21st day of the experiment. Statistical analyzes were performed using the MIXED method by SAS software with the effect of time as repeated measurements.
Results: Feeding forage from day one of age compared to day 21 of age (P=0.078) and pellet compared to ground diet (P=0.064) tended to increase protein digestibility throughout the period. On the other hand, feeding pellet compared to ground starter increased fat digestibility throughout the period (P=0.033). Feeding forage from one day of age compared to 21 days of age increased the digestibility of neutral and acid detergent insoluble fiber. Also, feeding pellet diet increased the digestibility of neutral and acid detergent insoluble fiber compared to ground. Also, feeding forage from one day of age compared to 21 days of age increased pH and cellulase activity and decreased rumen ammonia nitrogen. Also, cellulase activity was higher in pellet-fed groups than in ground-fed groups. An interaction between feed texture × time of forage initiation was observed, such that feeding pelleted feed with forage from 1 day of age had the highest cellulase activity, pH, and the lowest ammonia nitrogen. Feeding forage from 1 day of age compared to 21 days of age increased rumen acetate concentration. Also, calves consuming pelleted feed tended to have higher acetate concentration as well as higher levels of propionate and butyrate and total rumen fatty acids compared to ground feed. On the other hand, ground feed increased serum glucose concentration compared to pelleted feed, and forage consumption from 1 day of age led to a decrease in serum glucose and β-hydroxybutyrate levels.
Conclusion: Alfalfa intake at 10% at 1 day of age compared to 21 days of age resulted in increased rumen fiber digestibility, which is due to increased rumen health and higher rumen cellulase activity. Also, feeding pelleted compared to ground diets resulted in increased rumen fatty acid production. The interaction between feed texture and time of forage initiation showed that the use of forage at 1 day of age in calves consuming pelleted diets resulted in increased rumen function.
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