Beschreibung
The objective of this cross-sectional study was (1) to evaluate relationships between the prepartum metabolic status of dams and the colostrum quality as determined by Brix-refractometry and (2) to determine the influence of the prepartum metabolic status of dams on the serum immunoglobulin (Ig) and total protein (TP) concentrations of their dairy calves, taking other relevant management factors into account.
From March 2017 to March 2018, a total of 124 farms participated in the study. Farms were recruited from among the Thuringian Animal Health Service’s clientele (97 farms) and from the clientele of two large animal practices in Southern Bavaria (27 farms). Participation in the study was voluntary. Seven to ten multiparous cows per dairy farm about three to one weeks prepartum were selected based on the expected calving date. The clinical examination included rectal temperature as well as body condition score, lameness score, and degree of rumen fill. Where applicable, administration of anionic salts as a low dietary cation-anion difference-diet, the administration of vitamin E and selenium, and vaccination of dams during the dry period were recorded. Blood was harvested from the coccygeal vessels and urine samples were collected in tubes using a sterile stainless-steel bladder catheter. Clinical examination and sampling took place about three to one weeks before the expected calving date. In the laboratory of the Thuringian Animal Health Service, serum and urine samples were analyzed by automated spectrophotometry (Beckman Coulter Unicel D×C 600). Selected metabolites were serum concentration of cholesterol, bilirubin, urea, TP, albumin, non-esterified fatty acids (NEFA), calcium, phosphorus, magnesium, as well as serum activity of aspartate aminotransferase, glutamate dehydrogenase (GLDH) and creatine kinase, and urine concentration of calcium, sodium, creatinine, and potassium Net acid-base excretion was determined by titrimetric method. Selenium serum concentration was analyzed by an external laboratory (Synlab Analytics & Services Germany GmbH, Jena, Germany). Colostrum samples were collected after birth and analyzed using a digital Brix-refractometer. Calves were sampled between one and nine days of age. Blood was harvested from the jugular vein and analyzed for serum concentration of albumin and TP by automated spectrophotometry (Beckman Coulter Unicel D×C 600) and Ig was measured photometrically using an indirect proxy measurement (precipitation with sodium sulfate solution). In addition, the following data on newborn calf management was recorded for each farm: time and amount of first colostrum feeding, colostrum quality testing, first colostrum-feeding from the own dam, separate primary calf caretaker and birth control. Multivariable linear regression models with stepwise backward elimination of variables were used in the statistical analysis. Overall, 873 of the 1053 originally tested cows were included in the data analysis for question one. The data analysis for question two included 551 cows with their calves kept in herds where each calf received first-feeding colostrum from its own dam.
The following results were obtained in the data analysis for question 1:
• An increase of the serum activity of GLDH is associated with lower Brix values (p = 0.002).
• An increase of the serum concentration of calcium is associated with lower Brix values (p = 0.05).
• The concentration of serum globulins in the cow is positively associated with the Brix value of the colostrum (p < 0.01).
• Cows entering second parity have lower Brix values than cows entering third or greater parity (p < 0.01).
• Prepartum vaccination of cows leads to higher Brix values (p < 0.01).
• Cows with low-grade lameness show higher Brix values of the colostrum than cows with moderate to high-grade lameness (p = 0.02).
The following results were obtained in the data analysis for question 2:
• Increasing serum NEFA concentration of the cow is associated with higher serum
Ig concentration of the calf (p = 0.03).
• Calf serum concentration of albumin is negatively associated with calf serum concentration of Ig (p < 0.01).
• The Brix value of colostrum is positively associated with Ig and TP concentrations in the serum of the calf (p < 0.01 for Ig and TP).
• In herds with established frequent birth monitoring during night serum Ig- and TP concentrations are higher compared to herds with no birth monitoring at night (p = 0.05 and p = 0.03 respectively).
• Calves fed more than 2 liters of colostrum at first feeding have higher serum Ig- and TP concentrations compared to calves fed 1-2 liters (p < 0.01).
The results of this study provide evidence that prepartum metabolic health is associated with colostrum quality as well as the serum Ig- and TP concentrations of calves. The serum activity of GLDH, as well as serum concentrations of calcium, NEFA, and serum globulins are of particular interest. Further research on the pathophysiological mechanisms is desirable. Metabolic monitoring of close-up cows may contribute to identify potential causes of failure of passive transfer at individual and herd level. Prepartum vaccination of the cows and whole-day birth monitoring, which enables timely colostrum supply and minimizes the risk of dystocia, were proven to be a relevant factor to improve APT and calf health.
