Document Type : Complete scientific research article
Authors
1
Department of Animal Science, Faculty of Agricultural Engineering, Semnan University. Semnan, Iran
2
Department of Animal Science, Faculty of Agricultural Engineering, Semnan University, Semnan, Iran
3
Department of Health Food Education, Faculty of Veterinary Medicine, Semnan University, Semnan, Iran
Abstract
Background and objectives: One of the most critical goals in the dairy cattle industry is calf rearing. The pre-weaning period serves as the foundation for calf health and proper growth, as optimal growth in accordance with the animal's genetic potential can reduce the age at first breeding and the slaughter age of male calves. The use of trace elements such as copper, manganese, zinc, and cobalt in the diet of pre-weaned calves plays a significant role in growth, health, and reducing weaning stress. These elements are available in both organic and inorganic forms. The objective of this study was to compare the effects of organic and inorganic supplements on growth performance, blood metabolites, and the alleviation of weaning stress in calves, using domestically produced chelated supplements as an alternative to imported supplements.
Materials and methods: In this study, 30 Holstein calves (on the first day after birth) with similar average body weight of 39.6 ± 0.4 kg were randomly assigned to three groups of ten calves each (5 males and 5 females) and subjected to experimental treatments. The experimental treatments included: a control group receiving inorganic mineral supplements, a group receiving Iranian organic mineral supplements (in the form of organic chelate complexes produced by Zista Group – Parsa Holding), and a group receiving a commercial foreign organic supplement (Availa Four). In all three groups, colostrum quality (Brix index ≈ 25), water and starter feed were similar. Calves were weaned at 75 days of age, and the total experimental period lasted 100 days. Parameters such as feed intake, average daily gain, blood metabolites, immunoglobulin G levels, immune-related enzyme activities, and mineral digestibility and absorption were measured. Data were analyzed in a completely randomized design using SAS software version 9.1 (2005), and means were compared at a significance level of 0.05.
Results: In this study, dry matter intake was affected by the experimental treatments only during the pre-weaning period (P<0.05). Accordingly, the highest dry matter intake was observed in the Availa-supplemented group (1320 g/day), while the lowest intake was recorded in the inorganic supplement group (1250 g/day) (P<0.05). A significant difference in body weight gain was observed among the experimental groups during the pre-weaning, post-weaning, and entire periods (with the Availa group showing the highest and the inorganic supplement group the lowest values, P<0.05). However, feed efficiency was not influenced by the experimental treatments. At weaning, the highest blood glucose concentration was measured in the inorganic group, and the lowest value was observed in the Availa (foreign) group (100.2 vs. 88.6 mg/dL). Additionally, the highest plasma beta-hydroxybutyric acid (BHBA) concentration was related to the inorganic group, and the lowest was observed in the domestic organic group (1.546 vs. 0.726). The highest cobalt absorption was recorded in the Availa group, and the lowest in the inorganic group (75.992 vs. 40.728). The highest organic matter and dry matter digestibility values were observed in the Availa group (74.116% and 87.764%, respectively), while the lowest values (70.600% and 74.700%, respectively) were found in the inorganic group.
Conclusion: Throughout the study period, the Availa group demonstrated superior performance in various parameters, including blood glucose concentrations, beta-hydroxybutyrate levels, nutrient digestibility, mineral absorption, and body weight gain.
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