Assessment of Goat Colostrum Quality and Passive Transfer Status AASRP Research Summaries AABP Annual Conference 2019 St. Clair EV, Russell RW, Van Saun RJ* Department of Veterinary and Biomedical Sciences Pennsylvania State University

Introduction Importance of Ig transfer from colostrum Fleenor and Stott, JDS 1980 Importance of Ig transfer from colostrum Health status Growth performance Consumption of adequate amount of high quality colostrum most critical factor in kid survival Methods to assess quality? AASRP Research Summaries 2019

Introduction Feeding of high-quality colostrum is the single most important event in a kid’s life to ensure viability and survivability Colostrum quality is based on concentration of immunoglobulin-G (IgG) Effectiveness of passive transfer is based on delivering sufficient quantity of colostrum in a timely manner relative to birth to achieve adequate blood IgG concentration that would be protective from disease In dairy calves: 10 mg/ml of serum IgG concentration is desired Heinrichs et al., USDA:APHIS:VC:NAHMS, 1992 AASRP Research Summaries 2019

Study Objectives Evaluate relationships between colostrum quality, feeding practices and evaluation methods of colostrum absorption Determine serum IgG concentrations in goat kids post-colostrum feeding Relate total IgG consumed to serum IgG concentration – evaluate any factors influencing serum IgG concentration Establish if any relationship between serum total protein and IgG concentration for evaluating colostrum intake AASRP Research Summaries 2019

Materials and Methods Colostrum and serum samples were collected from a commercial 900-doe goat dairy All procedures approved by Penn State IACUC Colostrum IgG determined by Brix and RIA methods Colostrum feeding protocol: 6-8 oz twice within 24 hrs. Blood samples were collected from kids between 1-4 days post birth and frozen for analysis Herd records were collected: Ewe data: age, LN, # kids (live, dead), dry period, previous lactation lengths, previous production, date of kidding Mode of feeding (bottle, tube, bucket), volume, timing relative to birth AASRP Research Summaries 2019

Materials and Methods Kid serum samples (n=57) were analyzed for total IgG concentration Total serum IgG concentration was determined with an ELISA assay (ZeptoMetrix, Buffalo, NY) Kid serum samples analyzed for Total Protein (TP; g/dL) by a digital refractometer (MISCO, Solon, OH) Hemolyzed samples resulted in extremely high TP and were removed from data analysis (n=30 for analysis) Efficiency calculation assumed 10% of birth weight as blood volume to determine total IgG in blood AASRP Research Summaries 2019

Statistical Analysis SAS 9.4 Proc GLM, ANOVA to determine significant effects on serum IgG concentration or IgG absorption efficiency: Model main effects were: IgG consumed; Timing to colostrum feeding and their interaction Other effects tested included ewe age, LN, #kids, dry period length, kid age at bleeding Correlation and regression modeling were used to determine predictive relationship between serum IgG and total protein concentration AASRP Research Summaries 2019

Results Paired (n=114 total) Brix and RID determinations were performed on 58 individual and 56 pooled doe colostrum samples. These samples were all post-thaw while 58 Brix determinations were made on fresh colostrum samples Mean ± standard deviation (median, range) RID concentrations for all samples was 71.0 ± 36.8 mg/mL (74.2 mg/mL, 4.2-180.5 mg/mL). Paired (n=114 total) Brix and RID determinations were performed on 58 individual and 56 pooled doe colostrum samples Overall post-thaw Brix determinations were 20.7 ± 4.5 (20.3, 8.7-34.3). Fresh sample mean Brix values were 21.2 ± 4.7 (21.7, 9.1-34.0) AASRP Research Summaries 2019

Brix Determination Brix measurements determined in fresh and thawed colostrum were highly correlated (P<0.0001) for all (r=0.97), individual (r=0.98) or pooled (r=0.76) samples. Similarly, post-thaw Brix and RID measures were highly correlated (P<0.0001) in overall (r=0.85), individual (r=0.89) and pooled (r=0.77) samples. Accounting for type of sample (individual vs pooled) influenced (P=0.045) the association between Brix in fresh and post-thaw samples (r2=0.94, P<0.0001) RID (mg/mL) = 6.97(Brix)-73.65 (r2=0.73, P<0.0001) AASRP Research Summaries 2019

Results Mean ± SD Median Range Serum Total Protein, g/dL 6.0 ± 0.8 6.0 4.5 – 7.2 Serum IgG, mg/mL 15.8 ± 7.3 15.3 3.1 – 36.1 First feeding colostrum IgG, g 17.6 ± 6.3 18.0 6.0 – 39.0 Total colostrum IgG, g 35.0 ± 11.2 36.1 11.9 – 64.3 Time to first feeding, min 106 ± 136 60 5 - 765 IgG Absorption Efficiency, % 16.8 ±8.8 16.4 3.6 – 52.9 AASRP Research Summaries 2019

Factors influencing serum IgG concentration: Results Factors influencing serum IgG concentration: Total IgG consumed showed the greatest influence (P=0.0020) with no effect of method of feeding or time to feeding. Amount of IgG fed at 1st feeding (P=0.0069), volume at first feeding (P=0.10), time to second feeding (P=0.061) and age (P=0.047) accounted for more variation (r2=0.45, P=0.0093) in serum IgG concentration than total IgG consumed (r2=0.36, P=0.013). Serum TP (P<0.0001), amount IgG at first feeding (P=0.083), kid age (P=0.017) and interaction of amount at first feeding and kid age (P=0.033) influenced IgG concentration (r2=0.82, P<0.0001) AASRP Research Summaries 2019

Results Factors influencing serum TP: Overall model (P<0.0001) accounting for time to first and second colostrum feedings, amount fed, age of kid and serum IgG concentration accounted for 84% of variation in TP, but only serum IgG was significant (P=0.0003) Serum IgG concentration alone accounted for 73% of variation in serum TP (P<0.0001) Incorporation of age at bleeding (P=0.08) only slightly improved the relationship between TP and serum IgG concentration (r2=0.76, P<0.0001). Best model (r2=0.82, P<0.0001) included serum IgG (P<0.0001), first feeding amount (P=0.05), kid age (P=0.008) and interaction of first feeding amount and age (P=0.01) AASRP Research Summaries 2019

Serum IgG Relationships AASRP Research Summaries 2019

Results Total IgG consumed was negatively associated (P=0.012) with IgG absorption efficiency Time to second feeding (P=0.023) and IgG amount at second feeding (P=0.015) explained the greatest amount of variation (r2 = 0.23, P=0.0016) in calculated efficiency of colostrum absorption AASRP Research Summaries 2019

Conclusions Brix refractometer can accurately evaluate IgG content in goat colostrum similar to dairy cattle These data suggest feeding a total of 35 g IgG in two feedings can achieve a serum IgG concentration of 15 mg/mL A serum total protein value of 6.0 g/dL is associated with a serum IgG concentration of 15 mg/mL Further research to assess the relationship between health status and IgG transfer to better define passive transfer guidelines. AASRP Research Summaries 2019

Acknowledgements Cypress Grove Chevre goat dairy and farm crew Dr. Andrea Mongini Louise Byler for statistical support American Dairy Goat Association for partial funding Department of Veterinary & Biomedical Sciences for partial funding AASRP Research Summaries 2019