Physiological and Pathological Factors Influencing Bovine α-Lactalbumin and β-Lactoglobulin Concentrations in Milk

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Abstract
Bovine .alpha.-lactalbumin and .beta.-lactoglobulin concentrations were determined by radial immunodiffusion in 354 milk samples from uninfected and 98 samples from infected quarters from 42 Holstein-Friesian cows taken at 30, 150 and 270 days of lactation. .alpha.-Lactalbumin and .beta.-lactoglobulin concentrations were not affected by quarter location. The .alpha.-lactalbumin decreased at the end of lactation and in samples collected beyond 2nd lactation. The .beta.-lactoglobulin concentration increased with stage of lactation. There was a positive correlation between .alpha.-lactalbumin and .beta. lactoglobulin (r = 0.12). Milk from uninfected quarters had mean .alpha.-lactalbumin and .beta.-lactoglobulin concentrations of 1.47 and 4.6 mg/ml, respectively. Milk from quarters infected by major pathogens or Corynebacterium bovis had less .alpha.-lactalbumin. Milk from quarters infected by minor pathogens had less .beta.-lactoglobulin. There was a negative correlation between .alpha.-lactalbumin concentration and somatic cell count (r = 0.31), which was amplified by infection status of quarters. No correlation was noted between somatic cell count and .beta.-lactoglobulin concentration when considered over the whole sampling period, but the correlation became negative in quarters infected by major pathogens.