Controlling energy intake during the dry period may help dairy cows ward off metabolic disease in early lactation. Now researchers want to know what effect this type of dry period diet has on the immunological status of newborn calves.
To find out, researchers at the University of Illinois fed close-up cows either a stepwise moderate energy diet or a controlled energy diet during the last 21 days of gestation. All cows received the controlled energy diet during the far-off dry period (50 to 21 days pre-calving).
Serum IgG concentration, serum total protein and albumin levels of the calves born to these dams were not affected by treatment diet, say the study’s authors in a research abstract presented in March at the 2011 American Dairy Science Association Midwestern sectional meeting in Des Moines, Iowa.
However, calves born to dams fed moderate energy tended to have higher insulin concentrations than calves born to dams fed controlled energy during late gestation. There also seemed to be more neutrophil activity in the blood of calves whose dams were fed the moderate energy treatment. Neutrophils are a type of white blood cell responsible for fighting infection.
“Nutrient status of the cow during late gestation could impact immunological status of the newborn calf, although the mechanisms are not known,” say study authors.
Target immunity levels for Holstein calves can be found in the Dairy Calf & Heifer Association’s Gold Standards I. Serum total protein is one measure of immune status. It should be greater than 5.2 grams per deciliter in animals two to seven days of age.