An evaluation of on-farm and laboratory analysis to assess colostrum quality of UK dairy ewes
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An evaluation of on-farm and laboratory analysis to assess colostrum quality of UK dairy ewes
Title: “An evaluation of on-farm and laboratory analysis to assess colostrum quality of UK dairy ewes”
This study was shortlisted for the 2024 Thesis of the Year Award and was completed as part of Molly Bampton's studies for a BSc (Hons) in Agriculture at Harper Adams University, supervised by Emma Bleach.
Over the past 50 years, European small ruminant dairy production has doubled, accounting for 1.3% of the global milk production. Currently, there is a distinct gap in our knowledge of factors influencing colostrum quality in ewes. Brix refractometers are recommended for use in assessing ewe colostrum quality, which can help estimate IgG levels. Lambs should receive colostrum for the first 36 hours post-partum, to enable IgG to be absorbed to achieve passive transfer of immunity.
Previous research has indicated that the variation in colostrum quality can be impacted by different factors: Breed, IgG, dry matter, and management strategies. Additionally, studies have reported variations in the colostrum composition, such as IgG (mg/ml), protein (%), fat (%), and lactose (%). This makes creating a benchmark an issue because of this variation. This study aimed to evaluate the quality of colostrum and investigate the constituents of dairy ewe colostrum.
Colostrum samples (n=31) from pedigree Friesland ewes were collected on a farm using an indoor system <3 hours post-partum. Brix testing occurred on the farm, and samples were then frozen and taken to Harper Adam’s University laboratory and thawed 7 months after initial collection. Laboratory analysis of the colostrum composition (dry matter, crude protein, total fat etc) to calculate significance. To measure the components, influence on colostrum in Brix (%) a multiple linear regression was used in GenStat 23rd edition.
Firstly, this study identified that the quality of colostrum was not impacted by the freeze-thawing process and can provide an accurate comparison. The average Brix value was 27.4% which in this study was categorised as ‘good’ and similar to the previous studies results. The quality of colostrum samples was significantly (p=<0.001) influenced by dry matter (%), crude protein (%), and total fat (%) (table 1 below).
In addition, the colour profiles showed to indicate the Brix quality (p=0.034). Samples that were darker in colour had the highest Brix value (32%), dry matter (51.7%), and crude protein (25.8%). Other factors such as viscosity, parity, and litter size showed no statistical influence on Brix percentage.
The study supports the use of a Brix refractometer, and the composition of colostrum is likely due to flock management systems. The author noted that the limitations of this study include the number of samples, volume of colostrum, and the unbalanced distribution of parity and litter size. Overall, the data collected in this study are reflective of the Friesland breed in a UK dairy flock management system. This study provides a step in the right direction, contributing to the current body of knowledge on ewe colostrum in the UK.
Summarised by Doctor Issy Bacon, Animal Health Lecturer, Hartpury University.
