نوع مقاله : مقاله پژوهشی
نویسندگان
گروه تغذیه دام و طیور، دانشکده علوم دامی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: The first three months of a calf’s life play a crucial role in determining its future health and productivity. During this critical period, the physiological state of the animal includes the ability to absorb large molecules, especially immunoglobulins, from the intestine, as well as a high susceptibility to gastrointestinal infections and diarrhea. Moreover, the economic success of industrial dairy farms depends to a significant extent on the proper rearing of replacement calves. In modern dairy farming systems, calves are usually separated from their mothers immediately after birth and artificially fed whole milk or milk replacers. This separation deprives the calves of the natural microflora of the mother’s saliva and other cows, slowing down the formation of beneficial microbial communities and even creating an imbalance in the microbial flora of their digestive tract. On the other hand, if appropriate nutritional and management strategies are not adopted at this critical stage of life, the growth, health and production performance of calves will be negatively affected. Calves are at higher risk of mortality compared to other livestock due to specific physiological characteristics such as a weak immune system and the gradual transition of the digestive tract from processing milk to solids.
Materials and Methods: This study was conducted to compare the effect of feeding chelated and inorganic forms of trace elements (cobalt, iodine, selenium, zinc, manganese, iron and copper) on performance, blood parameters and skeletal growth indices of suckling Holstein calves. A total of 36 calves, aged 7 ± 3 days with an initial body weight of 36.2 ± 3.8 kg, were randomly exposed to three treatments with 12 replicates per treatment in a completely randomized design. Treatments included: 1- Control (without mineral supplementation), 2- Feeding with two grams of chelated supplement per calf per day. 3- Feeding with two grams of mineral supplement per calf per day. Calves were fed colostrum (10% of body weight) in the first three days of life and then from the fourth day to 60 days of age with four liters of milk twice a day (7 am and 7 pm). Water and starter feed were provided ad libitum. In order to investigate performance factors, calves were weighed on days 0, 30, and 60 to assess changes in body weight. Daily feed intake and refusals were recorded throughout the experiment. On day 60, fasting blood samples were collected from the jugular vein of calves using heparinized venoject tubes prior to the morning feeding to analyze blood parameters. In addition, skeletal growth indices including interocular distance, wither height, and body length were measured on the final day of the trial.
Results and Discussion: According to the results of the present study, supplementation with chelated minerals significantly improved 30-day and 60-day body weight, overall weight gain, and average daily gain (ADG) during both the first 30 days and the full pre-weaning period (P< 0.05). No significant differences were observed between calves receiving chelated and inorganic mineral supplements regarding 30-day body weight and ADG during the first 30 days. Supplementing calves' milk with chelate minerals increased total and daily dry matter intake, starter intake, and feed conversion ratio (P<0.05). Calves receiving chelate supplements had greater interocular distance compared to the other two groups (P<0.05). Also, the interocular distance, height at withers, and body length of calves receiving chelate supplements were greater than those in the control group (P<0.05); however, this difference was not significant with calves receiving inorganic supplements. No significant differences were observed in serum iron and copper concentrations among the treatment groups. However, supplementation with trace minerals increased serum concentrations of thyroid hormones triiodothyronine (T3) and thyroxine (T4) (P< 0.05). There was no significant difference in T3 concentration between the control and mineral supplement groups, nor between the mineral and chelated supplement groups. Similarly, T4 concentrations were comparable between calves receiving inorganic and chelated supplements.
Conclusion: The results of this study demonstrated that supplementing the milk of suckling calves with chelated minerals significantly improved their growth performance. Moreover, chelated mineral supplementation had a significant positive effect on skeletal growth parameters and starter feed intake. It also led to increased serum concentrations of zinc and thyroid hormones, including triiodothyronine (T3) and thyroxine (T4). Overall, the findings suggest that incorporating chelated mineral supplements into the milk diet enhances performance traits, skeletal growth, and measured parameters in suckling calves.
کلیدواژهها [English]
©2025 The author(s). This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source
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