Document Type : Research Paper
Authors
1 Department of Animal Science, Faculty of Agriculture, Bu-Ali Sina University
2 Department of Animal Science, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
Abstract
Introduction: The physical characteristics and nutrient composition of feed are among the most critical factors influencing animal health, performance, and feeding behavior. These factors not only directly impact the nutritional requirements of livestock but also play a pivotal role in enhancing production efficiency, improving product quality, and mitigating nutrition-related disorders. This study aimed to evaluate the effects of feed physical form during late gestation and early lactation in ewes on blood metabolites, antioxidant status, and lamb performance after birth.
Materials and methods: This study was conducted using 36 Mehraban ewes with an average body weight of 50.17 ± 2.09 kg and an average age of 3 to 4 years in a completely randomized experimental design. The experimental treatments included: (1) mash concentrate, (2) pelleted concentrate, and (3) pelleted total mixed ration (TMR). These treatments were provided to the ewes during the last two months of gestation and the first month of lactation. To evaluate blood biochemical parameters and antioxidant status, blood samples were collected from the ewes at three time points: 30 days before lambing, at lambing, and 30 days after lambing, prior to the morning feeding. Milk yield and milk fat content were also assessed on day 21 postpartum. Additionally, lamb performance was evaluated by weighing the lambs at birth and weekly until the end of the trial.
Results and discussion: The results indicated that feed intake during both the pre- and post-partum periods, as well as milk production, were significantly higher in ewes fed with pelleted total mixed ration (TMR) and pelleted concentrate compared to those fed with mash concentrate (P < 0.05). However, the milk fat percentage was not affected by the experimental treatments. Feeding pelleted TMR and pelleted concentrate significantly increased serum glucose and urea concentrations (P < 0.05), while other blood parameters, such as cholesterol, triglycerides, total protein, and liver enzymes, were not influenced by the treatments. Furthermore, feeding ewes with pelleted feed led to a significant reduction in malondialdehyde concentration and an increase in total antioxidant capacity at certain time points (P < 0.05), indicating a reduction in oxidative stress in animals fed this type of feed. Additionally, the body weight and daily weight gain of the lambs were influenced by the physical form of the feed consumed by the ewes at certain time points. Lambs born to ewes fed with pelleted TMR and pelleted concentrate had higher weight and daily weight gain between days 7 and 30 compared to those born to ewes fed with mash concentrate (P < 0.05). However, no significant difference in birth weight was observed among the different treatments.
Conclusions: Overall, the results of this study indicated that feeding ewes with pelleted total mixed ration (TMR) and pelleted concentrate during late gestation and early lactation can enhance ewe performance, improve lamb performance, increase certain biochemical parameters, and strengthen the antioxidant status of the ewes' blood. These findings underscore the significant role of feed physical form as an effective tool in optimizing animal health, production performance, and welfare.
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