Journal of Animal Production, Print ISSN: 2008-6776., Online ISSN: 2382-994X

Abstract Objective: The suckling calf is particularly susceptible to digestive and respiratory disease because of its immature immune system and increased mortality, making it one of the major challenges of the livestock industry. The nutritional strategy to enhance the performance of suckling calves by supplementing their diet with feed additives, such as probiotic and biochar, was evaluated in this study. Method: Twenty-eight female newborn Holstein calves (41.2 ± 3.8 kg) were used in a 2×2 factorial arrangement within a completely randomized design over a 70‑day experimental period. Experimental treatments were as follows:1- basal diet without additive (control), 2- basal diet with 2 g/day of probiotic, 3- basal diet with 1% biochar and 4- basal diet with 2 g/day of probiotic plus 1% biochar. The basal diet was formulated with a 10:90 forage-to-concentrate ratio to meet nutrient requirements. Water and starter feed were provided ad libitum throughout the experiment. Feed intake was recorded daily, body weight and skeletal growth changes were assessed every two weeks. Blood samples were collected on days 0 (birth time), 35 and 70, and fecal samples were collected to evaluate diet digestibility in the last week of the experiment from all calves. All calves were observed for three days at the end of the experiment to record their feeding behaviors (standing, lying, eating, and ruminating) and non-feeding behaviors (licking, sucking, and chewing on environmental objects). Results: Results indicated that calves that were supplemented with dietary biochar had significantly higher starter feed intake and weaning body weight compared with the non‑biochar groups (P<0.05). Wither height, hip height and abdominal circumference of the calves also increased with biochar supplementation (P<0.05). Concurrent supplementation with probiotic and biochar (treatment 4) further enhanced wither height and hip height (P<0.05). probiotic and biochar supplementation improved apparent digestibility of organic matter and crude protein (P<0.05), respectively, whereas the digestibility of other nutrients was unaffected by experimental treatments. Biochar supplementation also increased blood glucose concentration (P<0.05). Dietary treatments did not significantly affec any of the feeding behaviors. Interaction effects of probiotic and biochar were not significant on any of the parameters measured in this study. Conclusions: Overall, dietary supplementation with biochar, either alone or in combination with probiotic, showed significant positiv effects on performance, skeletal growth indices, and digestibility of nutrients in suckling calves, suggesting that biochar may be used as a functional feed additive to support early-life health and productivity.

Abstract Objective: High incidences of diarrhea and pneumonia, along with suboptimal growth, remain major challenges in the calf-rearing industry, leading to increased treatment costs, elevated mortality rates, and reduced profitability. Considering the crucial role of dietary energy in supporting immune function, promoting growth performance, and maintaining liver health during the pre-weaning period, this study aimed to evaluate the effects of supplementing dairy calf diets with varying levels of Lipidol and fat powder on growth performance, hematological and hepatic biochemical parameters, vital signs, and the incidence of diarrhea and pneumonia. The ultimate objective was to identify an effective nutritional strategy to enhance performance and reduce disease occurrence in pre-weaned calves. Method: In this study, thirty-six Holstein suckling calves (5 ± 2 days of age) were randomly allocated to four experimental treatments in a 2 × 2 factorial arrangement within a completely randomized design. The treatments consisted of a basal diet supplemented with either 0.15% or 0.30% Lipidol in combination with either 0% or 3% added fat powder. Body weight was recorded at the beginning and end of the experimental period, and daily dry matter intake was measured throughout the study. Physiological parameters, including respiratory rate, heart rate, and rectal temperature, were assessed at 30 and 60 days of age. Blood samples were collected at 08:00 h to evaluate hematological parameters (white blood cell count, red blood cell count, hemoglobin concentration, and hematocrit), liver enzyme activities (aspartate aminotransferase and alanine aminotransferase), and serum urea concentration. The incidence of common diseases, including diarrhea and pneumonia, was monitored throughout the rearing period and analyzed statistically using odds ratio estimates. Results: The results demonstrated that supplementation with 0.15% Lipidol, either alone or in combination with 3% fat powder, significantly increased final body weight compared with the other treatments. In contrast, supplementation with 0.30% Lipidol did not produce a comparable effect. Growth performance parameters, including total weight gain, dry matter intake, and feed conversion ratio, were not significantly affected by treatment. Hematological variables did not differ significantly among experimental groups. However, calves receiving 0.30% Lipidol combined with 3% fat powder exhibited significantly higher (p < 0.05) aspartate aminotransferase activity and serum urea concentrations, suggesting a greater metabolic burden on the liver under this treatment. Physiological parameters, including respiratory rate, heart rate, and rectal temperature, remained within normal physiological ranges at both 30 and 60 days of age, with no significant differences observed among treatments. Conclusion: The findings of this study indicate that dietary supplementation with 0.15% Lipidol enhances growth performance in suckling calves without inducing adverse physiological effects or increasing disease incidence. In contrast, the higher supplementation level (0.30%), particularly when combined with fat powder, was associated with elevated liver enzyme activity and serum urea concentrations, suggesting an increased hepatic metabolic load, likely related to intensified lipid metabolism.Hematological parameters and physiological indicators remained within normal ranges across all treatments, indicating no evidence of systemic stress or clinical disorders. Overall, these results suggest that supplementation with 0.15% Lipidol represents an optimal inclusion level for improving growth performance in suckling calves while minimizing potential metabolic risks.

Abstract Objective: Proper raising of suckling calves is important in creating a profitable productive herd. In this regard, the three important principles of nutrition, preservation of the environment and disease control will be effective in reducing losses caused by losses from birth to weaning. In recent years, efforts have been made in calf nutrition to find the best combination of starter diets to justify the best growth and health. Grain processing makes starch available to microbes and increases the rate and extent of starch degradation in the rumen. Considering that there is little information about the effect of barley processing on feed intake and performance behavior in dairy calves, therefore, this study aims to compare non-steamed flaked barley with milled barley on performance, fecal score, chewing behavior and blood parameters of Holstein suckling calves. Materials and Methods: In this study, 12 Holstein female calves aged 20 to 25 days and an initial body weight of 44±2.7 kg were used in two treatments and six replications. The treatments included: 1- starter diet containing milled barley, and 2- starter diet containing non-steamed flaked barley. The duration of the trial period was 35 days. The experimental diets were isoenergetic and isonitrogenous. On the 58th and 59th days of the experiment, feed intake behavior was calculated by recording activity for 24 hours. During the research period, the calf fecal score was also checked. To measure blood parameters on the 35th day of the experiment, blood was taken four hours after morning feeding using heparinized venoject tubes from the jugular vein of the calves. Results and Discussion: The results comparing the effect of milled and non-steamed flaked barley on the performance of Holstein calves showed that there is a significant difference between the calves fed non-steamed flaked barley in terms of final weight, weight changes, average daily gain (ADG), dry matter intake (DMI) and feed conversion ratio (FCR) than calves fed milled barley (P<0.05). The calves fed non-steamed flaked barley had more weight changes (11.66) during the experimental period. There was a significant difference in eating behavior, rumination, chewing and rest of calves between experimental treatments (P<0.05). The fecal consistency score, the number of calves with diarrhea and the average days with diarrhea were not affected by the treatments Blood glucose concentration of calves fed non-steamed flaked barley was higher than that of calves consumed milled barley (P<0.05). However, blood concentrations of triglyceride, cholesterol, urea, total protein, albumin, globulin and their ratio were not affected. Conclusion: The results of the present study showed that the use of non-steamed flaked barley compared to milled barley increased DMI and ADG, and improved FCR and eating behavior of dairy calves.

Abstract To determine the effect of mixed thyme and eucalyptus leaves aqueous’ extract on the performance and health of Holstein suckling calves, an experiment using 32 calves (16 females and 16 males) with 7±3 days old and an average weight of 40.4±3 kg was carried out in a completely randomized design with four treatments and 8 replicate for 70 days. The treatments were: diets with no extract (control); and diets containing10, 15, and 20 ml of extract (50 % thyme + 50% eucalyptus) in consumed milk. In order to evaluate changes in body weight, chest circumference and height, the data were measured and recorded on days 7, 28, 49, and 70 at 10 a.m. To determine the blood parameters, blood samples were taken from the jugular vein on the 70th days. It turned out that the extract can result in a higher mean body weight gain and larger body size (P <0.05). Moreover, thyme and eucalyptus extracts appeared not to have any effect on digestibility and feed intake, but feed efficiency improved with 20 ml (P <0.05). Fecal and eye secretion index in calves receiving diets containing 15 and 20 ml of extract improved compared to the control group (P <0.05). Also, adding 20 ml of the extract reduced the amount of glucose and increased the number of red blood cells and hematocrit in the blood of the receiving calves compared to other experimental groups. The findings indicated that adding 20 ml eucalyptus and thyme extracts in daily milk, can improve the performance and health of Holstein suckling calves

Abstract Effect of different processing methods of corn grain were investigated in 36 Holstein suckling female calves (body weight = 38.2 ± 1.20 kg) on performance and blood and ruminal parameters. Treatments were whole corn, ground corn, cracked corn and steam-flaked corn. Starter diets were mixed five percent of the chopped wheat straw and offered to calves from day 4. Milk was fed in a gradual step-up step-down method to all calves. Calves weaned at 71 days and total intake of starter and body weight of calves were measured until 84 days. Starter intake and ADG were significantly higher for cracked corn and steam-flaked corn than for ground corn and whole corn treatments in pre- and post-weaning and overall period (P≤0.01). At weaning and day 84, the average body weight of calves fed cracked corn and steam-flaked corn were significantly higher than those fed whole corn and ground corn treatments (P≤0.01). Treatments also affected serum protein of calves (P<0.05). According results of this study, feeding calves with cracked corn or steam-flaked corn increased feed intake and improved ADG and body weight through pre- and post-weaning periods.