Survey of colostrum quality and management practices on commercial dairy farms in the Eastern Cape Province of South Africa

Abstract

Bovine maternal antibodies are not transferred across the placenta during pregnancy and newborn calves are unable to produce their own antibodies within the first weeks after birth. As neonates are born agammaglobulinemic they need to acquire immunoglobulins (Ig) from their dam’s colostrum to acquire passive immunity. Colostrum fed to dairy calves, which is not timeous, of inadequate quantity and of unverified quality, might result in decreased neonate health. The aim of this study was to conduct a survey of the management of colostrum on commercial dairy farms, to estimate the quality of the Ig titre of colostrum fed to neonates and finally to recommend methods and techniques critical to the successful management of colostrum. The methods used included a questionnaire which was conducted as a structured interview on a one-on-one basis among 50 randomly selected commercial dairy farmers in the Eastern Cape Coastal Region of South Africa. The estimation of the colostrum Ig titre of colostrum fed to neonates was made by the on-farm measurement of specific gravity (SG) by making use of a commercially available KRUUSE colostrometer (Fleenor and Stott, 1980). A pooled colostrum sample, from each of the four quarters, from 90 randomly selected post-partum cows was collected on a leader commercial dairy farm. This method was used to compare colostrum samples from cows run under similar management practices. These samples were collected for analysis within 6 hrs of calving and were done over 3 seasons (autumn, winter and spring). Survey - The colostrum mass and timing of the initial feed are the most important factors when aiming to achieve adequate passive immunity. The results of the survey indicated that most of the farmers of this region feed an inadequate mass of colostrum (volume and Ig concentration) and only 52% of farmers surveyed feed colostrum less than 6 hrs post- partum. The majority (78%) of surveyed farmers did not follow up their initial colostrum feeding.Colostrum sampling - At the trial site only 10% (9 from 90 colostrum samples measured), were found to be of adequate SG quality. Cow age (parity), season of calving and colostrum temperature had an influence on the estimated colostrum SG. However, season of calving was found to have the greatest influence on SG values. These results were consistent with findings from previous studies that SG values from the cooler months were higher than those of the hotter months. Tables 4.7 (P=0.330), 4.8 (P=0.012) and 4.9 (P=0.005) showed that regression analysis confirmed that LS means across seasons were inadequately below the required 50 mg/ml Ig required for sufficient passive immunity. Tables 4.1 (P=0.164), 4.2 (P=0.011) and 4.3 (P=0.021) shows that season of calving had a much greater effect on CR than did parity, Table 4.5 (P=0.177). Table 4.4 shows that colostrum temperature has an significant effect on SG value. Recommendations for methods and techniques critical to the successful management of colostrum were made. These recommendations were based on the analysis of the data obtained from the questionnaire and the on-farm colostrum sampling study. The most important and critical management practices surveyed includes the timing of the cow and calf separation where it was found that only 30 from the 50 (60%) of the farms surveyed separate calves and dams at day (0), 19 from 50 farms (38%) separate at day (3-5) and 1 from 50 farms (2%) separate only at day 7 or later. Thus 40% of surveyed farms allow cows to nurse their calves. With regards to early exposure to pathogens this is a high risk management practice. Further to that, only 2 from 50 surveyed farms (4%) measure the colostrum quality fed to their calves and 48 from 50 farms (96%) feed colostrum of unmeasured quality. The mass of colostrum fed to calves is an important parameter for successful transmission of Ig. In the survey it was found that 28 from 50 farms (56%) feed 2L – 4L of colostrum and 11 from 50 farms (22%) feed 2L of colostrum. Thus 78% of farms feed approximately 50% of the amount of colostrum required for successful transmission of Ig. Finally only 1 from 50 farms (2%) freeze excess colostrum and 1 from 50 farms (2%) pool excess colostrum. Both these farms measure colostrum quality by colostrometer.