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: Calf rearing is one of the most important and sensitive management programs in livestock farms. Calves are a key factor in profitability; therefore, using appropriate nutritional methods for better growth and health is crucial. One such method is transitioning calves earlier from milk feeding to a dry diet. Faster feeding of the starter diet and the development of rumen villi prepare the calf for the transition period and reduce labor and feeding costs. Early weaning shortens the liquid feeding period. Since calves are susceptible to diarrhea and digestive issues during this phase, reducing its duration can be highly beneficial; However, one of the most important points in the livestock industry is animal nutrition, which is directly related to the growth, health, and mortality of livestock; Therefore, to achieve proper growth and health of livestock in order to improve production efficiency in animal husbandry, new methods are needed in the livestock nutrition sector.
Materials and methods: This study was conducted to compare the effect of feeding chelated and mineral forms of trace elements (cobalt, iodine, selenium, zinc, manganese, iron, and copper) on performance, nutrient digestibility, blood parameters, and stool consistency of suckling Holstein calves. Accordingly, calves with an age of 7±3 days and an initial body weight of 36.2±3.8 kg were divided into three treatments and 12 replications in a completely randomized design. Treatments included: 1- Control (without mineral supplementation), 2- Feeding with two gr of mineral supplement per calf per day 3- Feeding with two gr of chelated supplement per calf per day. For the first three days of life, calves were fed colostrum equal to 10% of their body weight. From day four to day 60, they received four liters of milk twice daily (7 AM and 7 PM).. During the experiment, calves had free access to water and feed. To assess performance, calves were weighed on days 0, 30, and 60 to monitor weight changes. Also, the amount of feed consumed and post-feeding was recorded daily. Fecal and feed samples were collected on days 55 to 59 for five days to perform digestibility tests. In order to measure blood parameters on day 60 of the study, fasting blood was drawn from the jugular vein of the calves before morning feeding using heparinized venoject tubes. Also, fecal score was measured daily.
Results and discussion: According to the results of the present study, adding chelated supplements improved the weight at 30 days, 60 days, weight changes, daily weight gain from 1 to 30 days, and the entire period of suckling calves (P<0.05). There was no significant difference in body weight at 30 days or daily weight gain (1–30 days) between calves receiving chelated and mineral supplements. Supplementing calf milk with chelated minerals increased total and daily dry matter intake, starter intake, and feed conversion ratio (P<0.05). The results of the present study show that adding mineral supplements and chelated trace elements to calf milk improved the digestibility of dry matter, organic matter, crude fat, and neutral detergent insoluble fiber (P<0.05). However, no significant difference was observed between calves receiving trace elements. According to the results, adding mineral elements to calf milk increased blood glucose concentration (P<0.05). However, the addition of trace minerals had no significant effect on the concentrations of cholesterol, triglycerides, urea nitrogen, total protein, albumin, and globulin. Serum zinc concentrations in calves receiving mineral supplements were higher than in the other two groups (P<0.05); while this difference was not significant with calves receiving chelated supplements. Calves in the control and chelated supplements groups had the highest (2.30) and lowest (1.86) fecal score among the experimental treatments (P<0.05).
Conclusions: Overall, this study suggests that supplementing milk with chelated minerals, rather than inorganic sources, improves performance traits, enhances stool consistency, and positively influences key physiological parameters in suckling calves.
کلیدواژهها [English]
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