PSII-3 - Daily Weather Patterns Associated with Colostrum Production in Dry Cows

Insufficient consumption of colostrum and/or intake of poor-quality colostrum reduces thriftiness and survival of dairy calves. Additionally, heat stress during gestation of primiparous Holstein cows can impact hormone synthesis, leading to decreased colostrum and milk production. Previous research has primarily focused on Holstein cows who have a larger frame compared to other breeds. It is possible heat stress may impact Jersey cow colostrum production differently. Therefore, the objective of this research was to determine the relationship between temperature-humidity index (THI) and colostrum volume and quality in Jersey cows. Colostrum data was collected from Jersey cows (n = 75) from three farms and compared to the average THI values during the dry period. Colostrum data included volume, Brix score, fat, true protein (TP), solids non-fat (SNF), lactose, somatic cell count (SCC), and urea. Daily air temperature and humidity records were determined via local weather stations and used to calculate THI values. These values were averaged for the far-off and close-up periods. The data were analyzed separately for each farm using linear regression models in R version 1.3.1073. Covariates included season, dry period length, date of colostrum collection, and parity. Close-up and far-off THI tended to predict an increased volume (β=0.3656; P = 0.0724) and somatic cell count (β=82.07; P = 0.0964) for Farm 1. Far-off THI was a significant predictor for Brix for Farm 2 (β=0.2482; P ≤ 0.01) and Farm 3 (β=-0.1762; P ≤ 0.01) and increased Brix score in Farm 2 but decreased it in Farm 3. THI was not a significant predictor for any other colostrum values. Based on these results, we suggest that an increased THI during the far-off period potentially increases Brix score without compromising other values. However, more research is needed to further investigate the effects of the close-up period on volume and of covariates on other values.