The effect of milk production level on host resistance of dairy cows, as assessed by the severity of experimental Escherichia coli mastitis

Abstract

-This study investigated the possible effects of milk production level on the host resistance of dairy cows. High (n = 18) and low (n = 18) producing cows on a research farm, which respectively produced 11 443 and 7 727 kg milk in their previous lactation, were compared. To enhance the possible differences in host resistance between high and low producing cows, the animals in both groups were metabolically stressed by overfeeding during the dry period or were fed according to requirements, resulting in four groups of nine cows. The metabolic status was monitored from two weeks pre-partum until 2.5-4.5 weeks post-partum. Host resistance was assessed by measuring the severity of experimentally induced Escherichia coli mastitis. Pre-partum blood glucose levels tended to be higher in overfed cows than in cows fed according to requirements. The post-partum energy balance was significantly more negative in high producing cows than in low producers, and tended to be more negative in overfed cows compared to cows fed according to the requirements. Post-partum plasma glucose, NEFA, β-OH-butyrate and urea concentrations were similar in the four groups. Plasma glucose concentrations were significantly lower and liver triacylglycerol concentrations were significantly higher in third than in second parity cows. Host resistance was not affected by the production level or feeding regimen. There were no significant correlations between the metabolic status and the severity of experimental E. coli mastitis, except for the relatively more severe mastitis in the cows with β-OH-butyrate concentrations above 1.4 mmol/L. In conclusion, milk production level did not affect host resistance in dairy cows, as measured by the severity of experimental E. coli mastitis. Even in a situation where cows were metabolically stressed by overfeeding, high producers were as able as low producers to cope with the demands of milk production, without consequences for host resistance. dairy cow / milk production / host resistance / metabolism / E. coli mastitis * Corresponding author: j.e.kornalijnslijper@vet.uu.nl 722 E. Kornalijnslijper et al.

The effect of supportive E. coli mastitis treatment on PMN chemiluminescence and subpopulations of T lymphocytes

“…This is confirmed in the literature (Kornalijnslijper et al 2003). The increase in the percentage of CD4 + lymphocytes is associated with a change in the immunological profile towards Th1 cells.…”

Escherichia coli, but notStaphylococcus aureustriggers an early increased expression of factors contributing to the innate immune defense in the udder of the cow

“…A significant number of studies used experimentally infected udders to study the events after pathogen contact [23,24,31].…”

“…The time of the experimental infection differed between 72 h [26] and 48 days [39] for both bacterial species, sometimes with repeated infections of the animals [26]. The infection dose varied for both S. aureus and E. coli between 50 and about 10 000 colony forming units (CFU per udder quarter) [23,55]. In addition, animals were not always prescreened for a prolonged absence of pathogenic bacteria within the udder prior to experimental infections [40].…”

Genome-wide methylation analysis reveals differentially methylated loci that are associated with an age-dependent increase in bovine fibroblast response to LPS

“…Mastitis severity has also been shown to vary greatly, even under controlled experimental settings where pathogen factors are held constant. This suggests host factors play a significant role in mastitis outcome [11]. Several studies have shown a dysregulated population of milk and serum neutrophils, along with greater concentrations of TNF-α and reactive oxygen species, during the peri-partum period when animals are highly susceptible to severe mastitis [12].…”