The major acute phase proteins of bovine milk in a commercial dairy herd.
BACKGROUND
Milk acute phase proteins (APP) have been identified and show promise as biomarkers of mastitis. However analysis of their profile in dairy cows from a production herd is necessary in order to confirm their benefits in mastitis diagnosis. The profiles of milk haptoglobin (Hp), mammary associated serum amyloid A3 (M-SAA3) and C-reactive protein (CRP) were determined in 54 composite milk (milk from all functional quarters of a cow's udder collected in a common receptacle) samples (CMS) from a commercial dairy farm. Milk Hp was also determined in individual quarter milk (milk from a single udder quarter) samples (QMS) (n = 149) of the cows. An ELISA was developed and validated for the determination of milk Hp while commercial kits were used for M-SAA3 and CRP assay respectively. Composite milk APP results were compared with cow factors including parity, stage of lactation, percentage protein and fat as well as somatic cell counts (SCC).


RESULTS
Composite milk Hp ranged from <0.4-55 μg/ml with a median of 3.5 μg/ml; composite milk M-SAA3 ranged from <0.6-50 μg/ml and had a median of 1.2 μg/ml, while CRP ranged from <1.80-173 ng/ml and had a median of 24.6 ng/ml. Significant correlations were found between composite SCC and Hp (P-value <0.009) as well as parity and Hp (P < 0.009), but not between M-SAA3 and SCC, M-SAA3 and Hp, M-SAA3 and CRP or M-SAA3 and parity. Milk CRP was correlated with % fat (P = 0.002) and % protein (P = 0.001) of the milk samples. The lack of correlation of SCC with the M-SAA3 and CRP could result from these APP being more sensitive to intra-mammary infection than SCC. Quarter milk Hp had a range of <0.4-420 μg/ml with a median value of 3.6 μg/ml, with 92 % of samples below 20 μg/ml.


CONCLUSIONS
Baseline values of Hp, M-SAA3 and CRP were established in composite milk from cows with normal SCC on the dairy farm. Parity was recognized as a possible confounding factor when diagnosing mastitis using Hp. The value of the APP, Hp, M-SAA3 and CRP as substitutes or to complement SCC in indicating udder inflammation, was demonstrated.
Institute of Biodiversity, Animal Health and Comparative Medicine, College of Veterinary Medical and Life Sciences, University of Glasgow, Bearsden Rd, Glasgow, G61 1QH, UK. f.thomas.1@research.gla.ac.uk.
Funmilola Clara
FC
Thomas
Institute of Infection Immunity and Inflammation, College of Veterinary Medical and Life Sciences, University of Glasgow, University Avenue, Glasgow, G12 8QQ, UK. Mary.Waterston@glasgow.ac.uk.
Mary
M
Waterston
School of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. Peter.Hastie@glasgow.ac.uk.
Peter
P
Hastie
School of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. Tim.Parkin@glasgow.ac.uk.
Timothy
T
Parkin
School of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK. Hayley.Haining@glasgow.ac.uk.
Hayley
H
Haining
Institute of Biodiversity, Animal Health and Comparative Medicine, College of Veterinary Medical and Life Sciences, University of Glasgow, Bearsden Rd, Glasgow, G61 1QH, UK. David.Eckersall@glasgow.ac.uk.
Peter David
PD
Eckersall
D000209:Acute-Phase Proteins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers; D002417:Cattle; D003612:Dairying; D005260:Female; D008414:Mastitis, Bovine / Q000378:metabolism*; D008892:Milk / Q000737:chemistry* / Q000166:cytology
D000209:Acute-Phase Proteins; D015415:Biomarkers