Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
Medicine & Epidemology
Non Technical Summary
Successful rearing of dairy calves requires ingestion of sufficient colostrum to provide passive immunity in order to reduce morbidity and mortality.1 Despite vast information on the importance of feeding colostrum, prevalence of failure of passive immunity (FPI) in calves remains high, ranging from 19-45%.Feeding of antibiotics to pre-weaned calves has been an accepted practice in order to address FPI as a risk for morbidity and mortality. Although colostrum absorption occurs from the calf's gut efficiently during the first 12-24 hours, studies have demonstrated that colostral immunoglobulin G (IgG) in the gut provides local immunity against viral and bacterial agents that cause diarrhea in calves older than 24 hours. Diarrhea is the most common disease in pre-weaned calves, hence oral administration of colostral IgG may provide local immunity thereby reducing use of antibiotics and treatment days in calves older than 24 hours. To the investigators' knowledge, no peer-reviewed studies have evaluated the use of colostral IgG supplementation as part of management of pre-weaned calves older than 24 hours, with diarrhea. We anticipate that the results of the proposed study will help producers better manage calf diarrhea on dairies and calf ranches.We hypothesize that oral supplementation with colostral IgG in dairy calves with diarrhea will reduce treatment events (including antibiotic treatments) and deaths. The objectives of this study is to 1) determine the effect of oral colostral IgG supplementation for 14 days on the number of treatment events, weight gain and mortality in pre-weaned calves with diarrhea and 2) determine the effect of oral IgG supplementation for 14 days on treatment duration in pre-weaned calves with diarrhea.We anticipate that the results of this study will generate recommendations on using colostrum to manage diarrhea in calves and reduce the need or longer duration of treating calves with antibiotics.
Animal Health Component
50%
Research Effort Categories
Basic
40%
Applied
50%
Developmental
10%
Goals / Objectives
Justification - In January 2017, FDA's guidance documents 209/213 will phase out the use of medically important antibiotics (MIA) as growth promoters and the modernization of the veterinary feed directive (VFD) allowing producers to add MIA to feed for therapeutic and prevention uses, and only under veterinary approval, and transfer of all over the counter (OTC) drugs into the previously described VFD. The changes to the prophylactic and metaphylactic use of antibiotics in livestock are due to increased concerns for antibiotic resistance and its potential adverse effects on human health. Due to potentially higher prevalence of failure of passive immunity in calves and common use of prophylactic or metaphylactic antibiotics therapy on calf ranches, these facilities are a focus for finding alternatives to antibiotic use in calves with diarrhea.Documented importance to California - Calf ranches are a vital part of the $12.8 billion California livestock industry. Management of calf diarrhea with alternatives that reduce antibiotic use will contribute toward reduction of antibiotic resistance. The research proposal fits within the high priority issues of alternatives to medically important antimicrobial drugs, antimicrobial and antiparasitic drugs, and sustainable production systems as well as the low priority issue of production systems management.Expected impacts and outcomes - The proposed study will provide recommendations to producers regarding the clinical utility of colostral IgG supplementation for management of calves with diarrhea.Research hypothesis:Oral supplementation with colostral IgG in dairy calves with diarrhea will reduce treatment events (including antibiotic treatments) and mortality.Specific objectives:a. Determine the effect of oral colostral IgG supplementation for 14 days on the number of treatment events, weight gain and mortality in pre-weaned calves with diarrhea.b. Determine the effect of oral IgG supplementation for 14 days on treatment duration in pre-weaned calves with diarrhea.
Project Methods
Project Description:a. Design: A double blinded randomized trial will be conducted on a single calf ranch (Merced County) raising ~10,000 replacement dairy heifers. At enrollment, calves will be weighed and identified upon arrival to the ranch. At 2 days of age, blood samples for serum IgG estimation by radial immunodiffusion (RID) will be collected. Following assessment of serum IgG concentrations, calves will be blocked into adequate passive transfer (IgG concentrations ≥1000mg/dL) and FPI (IgG concentrations <1000mg/dL) groups. The sample size required in each group (adequate transfer or FPI) will be at least 246 calves based on 5% level of significance, 80% power, assuming control calves are twice or more likely to be treated compared to treatment calves and a difference of at least 2 treatment days between the control (5d) and treatment (3d) calves, a standard deviation of 2 treatment days and a 20% drop-out due to loss of follow-up. Calves deemed to have non-septic diarrhea based on the fecal consistency scores and septic scores from the adequate passive transfer or FPI groups will then be randomly assigned using a random number generator by the study personnel into one of the following 3 groups (at least 82 calves in each group); non-supplemented control (NS); colostrum supplement (CS) and the placebo supplement (PS). The NS group of calves will act as a negative control by receiving no supplements in the milk replacer. The CS group calves will be supplemented with 10 g of IgG delivered through 70 g of colostrum replacer,b twice daily in the milk replacer for 14 days. The PS group calves will be supplemented with 70 g of a supplementc of similar matched nutritional value as the CS group calves, but without the IgG, twice daily in milk replacer for 14 days. Supplements fed to the PS and CS groups completely mix with milk replacer. Calves will be evaluated daily by blinded farm personnel for milk intake and signs of disease. All treatments for diarrhea based on farm records including number of days of treatment, antibiotic treatments and other medications performed will be recorded. Medical treatment of calves for diarrhea will be discontinued when fecal scores indicate normal fecal consistency. Calves will be weighed at the onset of a diarrhea event, 30 days of age and at weaning (60 days). Causes of mortality up to weaning will be recorded. To maintain blinding, farm personnel who will monitor calves for signs of diarrhea will not be present at the time of group assignment or mixing of the supplements with the milk replacer and containers with supplements will be identified by letters, for instance, A and B.