تاثير استفاده همزمان ايمونوگلوبولين Y، پروبيوتيك و الكتروليت بر عمكرد، سلامت و اسهال در گوسالههاي شيرخوار هلشتاين.

Introduction: The future of any dairy farm depends on the success of its calf and heifer-raising programs. Regarding the risk of gastrointestinal diseases and the prevalence of diarrhea, suckling calves are among the most sensitive animals in dairy herds. Gastrointestinal diseases are most prevalent in the first two weeks of calves' life and are the reason for 32% of deaths. In addition to short-term economic losses, diarrhea in female calves will delay sexual maturity and reduce milk production performance in the first lactation period. The use of antibiotics to prevent and treat diarrhea in suckling calves is always limited due to antibiotic resistance and some side effects. Research shows that between different anti-diarrhea feed additives, prebiotics and probiotics have the most positive effects in the first weeks of suckling calves' lives. In addition, it has been demonstrated that immunoglobulin Y can be effectively used to inhibit calves' gastrointestinal pathogens such as Escherichia coli and Salmonella species. Also, the use of electrolytes during diarrhea to prevent dehydration in young animals has been known to be positive. However, the synergistic effects of the simultaneous use of the mentioned additives are not clearly defined. Therefore, the present study was conducted to investigate a combination of immunoglobulin Y, probiotics, and electrolytes' effect on growth performance, feed intake, fecal consistency, health status, and blood parameters of Holstein suckling calves. Materials and methods: In this study, 24 suckling Holstein calves from birth to 28 days old were divided into two experimental groups (12 replications in each group) in a completely randomized design. The experimental groups included: 1) the control group (without additive) and 2) the group that received 10 grams per day of an anti-diarrheal feed additive contained 1.2 grams of probiotics with 5×10⁸ cfu/g, 1 g IgY, and 7.8 g electrolytes. All animals had free access to clean water and the ad libitum basal starter feed. The anti-diarrheal additive was dissolved in the calves' morning meal colostrum or milk. Feed intake, growth performance, and Escherichia coli fecal count were measured weekly. Rectal temperature and calves' fecal scores were evaluated daily (according to the method provided by Wisconsin University). Also, at birth, 14 and 28 days, blood samples were taken from the jugular vein. The repeated measurement data were analyzed by the MIXED procedure of the SAS version 9.4 statistical software. The means were reported as LSMEANS, and the significance level was considered as P<0.05. Also, for the statistical analysis of the fecal scores data, the days of each score were counted. Results and discussion: The results showed that the average daily weight gain in the third week in the antidiarrhea group was significantly higher than the control group (P<0.05). As a result, the live weight of the third and fourth weeks in the anti-diarrhea group was significantly higher than the control group (P<0.05). The starter intake in the anti-diarrhea group was 25% higher in the third week and 12% higher in the whole period than in the control group (P<0.05). Also, the feed conversion rate in the anti-diarrhea group in the second and third weeks was significantly lower than the control group (P<0.05). No significant difference was observed in the blood urea nitrogen, glucose, albumin, cholesterol, and triglyceride concentrations. Also, the anti-diarrheal additive had no significant effect on the count of white blood cells and the percentages of lymphocytes, neutrophils, monocytes, and eosinophils. According to the results, the anti-diarrhea additive had no significant effect on the calves' rectal temperature. The count of fecal Escherichia coli in the anti-diarrhea group was significantly lower than the control group in the first week, the first two weeks, and the whole period (P<0.05). The anti-diarrhea additive led to a significant increase in the number of days with zero scores (improvement of feces consistency) and a significant decrease in scores two and three (reduction of diarrhea prevalence) in calves (P<0.05). The results showed that in the first, second, and third weeks, the number of days with diarrhea significantly decreased in the anti-diarrhea group (P<0.05). In addition, the anti-diarrheal additive led to a significant decrease (58%) in the diarrhea length period. According to the period length and hardness of diarrhea, the cost of treating diarrhea in 28 days was estimated to be 830000 Rials and 470000 Rials in the control and anti-diarrhea groups, respectively. Therefore, the anti-diarrhea additive resulted in a 43% reduction in treatment costs. Conclusions: The results of the present study showed that the supply of an anti-diarrheal additive containing probiotics, immunoglobulin Y, and electrolytes to suckling calves led to a significant increase in growth performance, starter intake, improvement in feed conversion rate, reduction in the count of fecal Escherichia coli, and shortening of the diarrhea duration period. However, this additive did not affect rectal temperature, white blood cell status, and blood parameters such as glucose, cholesterol, triglyceride, albumin, total protein, and blood urea nitrogen. Therefore, the anti-diarrheal additive can reduce the prevalence, duration, and grade of diarrhea and its harmful effects and improve suckling calves' growth performance and health status. [ABSTRACT FROM AUTHOR]