Date

3-2012

Degree Name

BS in Dairy Science

Department

Dairy Science Department

Advisor(s)

Leanne M. Berning

Abstract

The objective of this study was to determine the success of current calf management protocols at the Cal Poly dairy by measuring Immunoglobulin (Ig) uptake at 48-hours post-partum, and by following mortality rate through weaning. By measuring serum protein concentrate (SPC) and using it as a direct indicator of Ig uptake we were able to grade the rate of passive immunity. Serum protein concentrate levels were obtained using a refractometer, and were measured in degrees Brix (°Bx). Blood samples were acquired via jugular venipuncture at the 48-hour mark from a mixed breed, mixed gender sample comprised of both Holstein and Jersey breeds of Cal Poly calves (n=73). Samples were collected over three winters (Jan.-Mar.). With 7 total calves lost out of the original sample, the true mortality rate is 9.6%. Due to incomplete or missing data on 16 of the calves within the sampling range, our sample size was corrected to n=57, and the mortality rate amended to 12.3%. A scoring system was adapted to assign grade values to °Bx recorded for each sample. Ranges of °Bx to grade and description are: 7.0-5.5°Bx=A “Ideal”, 5.4-5.3°Bx=B “Borderline”, 5.2-5.0°Bx=C “Poor”, 4.9-4.5°Bx=D “Inadequate”,7.0°Bx= “Likely Dehydrated”. Results of the data collection showed 70.1% of calves fell within ideal range, 1.75% of calves were borderline, 1.75% of calves displayed poor uptake, 3.5% of calves received scores of inadequate uptake, and 1.75% showed scores of no uptake. The remaining 21.5% were likely dehydrated, alluding to the idea that calves did not initially receive adequate amounts of Ig. As a cost of inadequate transfer of immunity, calves are more susceptible pathogens known to cause diarrhea. Diarrhea leads less water in the blood translating into a higher percentage of protein concentrated in the serum. In an effort to discover statistically significant correlations between our results and pre-weaning mortality rate, statistics were run using the PROC PROBIT feature of the SAS program. No statistically significant conclusions could be reached when correlating SPC scores against breed, gender, or date of birth. When using the same model to compare actual SPC values against pre-weaning mortality rate, our data approached statistical significance (P>0.058). Nevertheless, these observations are congruent with the precept that adequate amounts of Ig lead to a decrease pre-wean mortality.

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