Developing a criteria to select colostrum samples of poor quality

View the project final report

• 2015 annual report

Commodities

• Animal Products: dairy

Practices

• Animal Production: animal protection and health

           Internal herd growth is a key indicator of profitability, so every heifer calf born on the farm should be treated as a future milk cow.  Good colostrum management is essential to the health of newborn animals, because it is directly linked to an adequate transfer of immunity to the calf. Optimal intestinal absorption of immunoglobulin G (IgG), the main antibody in blood, provides the calf with a means to defend itself against invading pathogens.  Failure of the calf to absorb an adequate concentration of IgG is associated with an increase incidence of morbidity and mortality in the first two months of life.

            Surveys have indicated that colostrum management on small farms is often inadequate.  Despite the availability of on-farm measurement tools, such as the colostrometer or refractometer, the majority of small dairy producers fail to assess colostrum quality.  Colostrum quality varies widely among cows, based on factors such as parity, udder health, leakage of colostrum before calving and calving difficulties.  The first objective is to assess the accuracy of the colostometer and the Brix refractometer in an average, small farm setting.  Because in a typical production setting it can be impractical to test the colostrum of every fresh animal, the second objective is to create guidelines for identifying animals with exceptionally poor colostrum.  Then, the colostrum from these animals can be discarded or supplemented.  Outreach efforts will include training farmers to properly test colostrum quality on-farm and providing selection guidelines to identify animals that produce colostrum of inferior quality.

           The first objective of this project is to assess the accuracy of both the colostometer and the Brix refractometer in an average, small farm setting.  The second is to create guidelines for identifying animals with exceptionally poor colostrum.  As a farmer, I fully understand that although colostrum management guidelines strongly recommend testing the colostrum quality of every fresh cow or heifer on the farm prior to feeding the calf, this recommendation is not practical for the small commercial dairy farm.  Farmers generally rely on some type of record keeping system to track information, such as milk production, somatic cell counts, length of dry period, voluntary and involuntary culls and calving difficulties.  Based on these records, farmers can identify particular cows that should have their colostrum assessed for quality.  If an animal’s colostrum is deemed to be of inferior quality, the colostrum can be discarded and replaced with either a colostrum replacer or stored high quality colostrum from another animal in the herd. 

            All of the cows and pregnant heifers at Hazel-Rod farm are housed in a tie-stall barn, with seasonal access to pasture.  Dry cows and pre-fresh heifers are moved to a particular section of the barn, where they will be assured individual access to a complete, balanced diet.  Daily feed intake, fecal output and overall animal health is visually monitored on a daily basis.

            Cows and heifers are milked for the first time within 6 h of calving.  Colostrum is collected directly into a clean, stainless steel bucket milker. The bucket milker and milking claw is cleaned with the same system and chemicals used to clean the milk pipeline.  Immediately after collection, the colostrum is transferred directly from the bucket milker to a clean calf bottle. 

            Parameters such as calving difficulty and leakage of colostrum prior to calving will be recorded for each cow.  Parity of the cow and SCC for the previous lactation, if applicable, will be recorded, as well. The colostrum of every cow and heifer will be tested for IgG concentration via colostrometer and refractometer at the time of collection, which is immediately prior to feeding the newborn calf.  IgG concentration of each sample will be recorded for both the colostrometer and refractometer. 

            Colostrum samples with IgG concentrations of less than 50 mg/ml will not be fed to the calf.  Colostrum that measures above 50 mg/ml IgG concentration will be fed to the calf.  Typically heifer calves are fed 3 quarts of colostrum at first feeding and bulls are fed 4.5 quarts.  Each animal gets an additional 3 quarts of colostrum 12 h after the first feeding.  Animals are fed via milk bottle, unless they fail to consume colostrum within the first 12 h.  If they will not consume colostrum from a bottle, the calf will be fed colostrum via an esophageal feeder.

            Five small aliquots (5 mL) of each colostrum sample will be frozen for IgG ELISA analysis. ELISA has been chosen over radial immunodiffusion, because ELISA is more precise, accurate and less labor intensive.  In order to minimize the effect of freeze/thaw cycles on sample quality, sample aliquots will only be thawed once and then discarded.  ELISAs will be run in the molecular biology lab at Mansfield University.  The head of the Biology Department has agreed to help me identify an undergraduate biology student with an interest in animal agriculture.  I will work with and train the student to run an ELISA for bovine IgG on the colostrum samples. All samples will be run in duplicate.

             The resulting ELISA values will be compared to the refractometer and colostrometer values via a statistical analysis. The selection criteria for animals that may be at risk of producing low quality colostrum will be any animal with one of more of the following characteristics: high SCC or chronic mastitis in the previous lactation, calving difficulties that could be linked to nutritional deficiency during the dry period, leakage of colostrum prior to calving and primiparous animals.  Statistical analysis will also be used to determine possible correlations between lower quality colostrum and animals that fit the selection criteria.  I have been trained to run statistical analysis, and have done so for previous research projects, so I will run the analysis.

           Based on our DHIA records, we should average three heifers and four cows calving per month.  Ideally, we would like to examine the colostrum from 20 heifers and 20 cows.  Based on our calving projections for the spring and summer of 2015, it should take six months to reach our set number of heifers and cows.  Based on a mid-May 2015 start date, I will collect colostrum samples from May 2015 – November 2015.  In the event of my absence, I will train two employees to measure colostrum with both the colostrometer and refractometer and to properly aliquot and store a sample of colostrum.  The bovine IgG ELISA will be run periodically throughout the sampling period by the undergraduate student and I.  I will do a statistical analysis of the data in December 2015 and review the data with my technical advisor.  With the help of the local Agriculture Extension Agent, outreach efforts will commence in January 2016.

           In January 2016, I will create a pamphlet that gives a step-by-step guide to using a colostrometer and refractometer and highlights the benefits of using these tools on-farm.  This pamphlet would be available at the county extension office, local farm supply stores, local Pennsylvania Holstein events and the Tioga County Fair.  In addition, the Tioga County Agriculture Extension Agent has agreed to help facilitate a demonstration workshop day.  The ideal time for a workshop day would be in February of 2016, because farmers will not be busy prepping for the upcoming planting season yet.  Lastly, if the selection criteria data proves significant, I will submit an article to Farmshine Newspaper and the Journal of Dairy Science.