Composition and Functional Capacity of Blood Mononuclear Leukocyte Populations from Neonatal Calves on Standard and Intensified Milk Replacer Diets

Abstract

Effects of increased dietary energy and protein on the composition and functional capacities of blood mononuclear leukocyte populations from milk replacer-fed calves were investigated. Holstein bull calves (average age: 4.2 d; n = 19) were assigned randomly to one of two treatment groups. Treatment 1 calves (n = 9) were fed a 20% crude protein, 20% fat milk replacer at a rate of 1.4% body weight of dry matter/d for 8 wk, whereas treatment 2 calves (n = 10) were fed a 30% crude protein, 20% fat milk replacer at a rate of 2.5% body weight of dry matter per day. Composition and functional capacities of mononuclear leukocyte populations from blood samples collected at 4, 18, 32, 46, and 60 d of age were characterized by flow cytometry and ex vivo cell function assays. From 11 to 60 d of age, the mean daily weight gain of treatment 2 calves (1.20 kg/d) was greater than daily weight gain of treatment 1 calves (0.55 kg/d). At 60 d of age, the mean body weight of treatment two calves was 53% (39 kg) greater than the mean body weight of treatment 1 calves. Total numbers of blood leukocytes and the composition of the mononuclear leukocyte population were unaffected by the plane of nutrition. Mitogen-induced DNA-synthesis and immunoglobulin M secretion also were unaffected by dietary treatment. Blood mononuclear leukocytes from calves on intensified diets, however, produced less interferon-gamma and more inducible nitric oxide, suggesting that increased dietary energy and protein affects specific aspects of leukocyte function associated with cell-mediated immunity. The impact of altered interferon-gamma and NO production on the calf s susceptibility to infectious disease are not known. Mononuclear leukocyte populations from all calves also demonstrated age-related changes in composition and functional capacity, likely reflecting natural exposure to infectious agents and maturation of the calfs immune system.

Plane of nutrition during the preweaning period but not the grower phase influences the neutrophil activity of Holstein calves

“…The innate and adaptive branches of the immune system are not mutually exclusive, so more microbial-induced activation of neutrophil responses may improve the adaptive immunity and the subsequent health of calves. The data from Pollock et al (1994) and Nonnecke et al (2003) both report that calves fed LPN had greater measures of adaptive immunity (mitogen-stimulated IFN-γ and antigen-specific IgA and IgG 2 ), which may be due to differences in microbial exposure or the microbiome. This is largely speculative, but it is important to note that an evaluation of microbial exposure, the microbiome, and adaptive immunity should be included in future research on the role that plane of nutrition plays in leukocyte responses and health of calves.…”

“…Nonnecke et al (2003) found that blood mononuclear leukocytes produced less mitogen-induced IFN-γ and more inducible nitric oxide from calves fed an HPN compared with calves fed a low plane of nutrition (LPN). Pollock et al (1994) also reported that calves fed an HPN had decreased concentrations of antigen-specific IgA and IgG 2 .…”

Effects of hydrolyzed yeast supplementation in calf starter on immune responses to vaccine challenge in neonatal calves

“…Davis et al (2004) found a tendency toward a lower level of neutrophils and a greater proportion of lymphocytes in blood of mannan-fed weanling pigs. In addition, Nonnecke et al (2003) reported that total numbers of blood leukocytes and the composition of the mononuclear leukocyte population from neonatal calves were affected by level of energy and protein intake. To obtain more insight into the effects of yeast products on blood cell composition in an experimental infection model using neonatal calves, we conducted blood cell composition analysis.…”

Effects of different liquid feeding strategies during the pre-weaning period on the performance and carcass characteristics of dairy bull calves

“…The disadvantages of providing more milk or MR include reduced solid feed intake during the pre-weaning period (Terré et al, 2007;Huuskonen & Khalili, 2008;Weary et al, 2008) and slower rumen development (Khan et al, 2007). It is concluded that a greater nutrient supply through an increased amount of milk appears to improve the immune function (Nonnecke et al, 2003) and long-term performance of heifer calves (Bach & Ahedo, 2008); for example, reducing the age at first breeding and increasing the firstlactation milk yield. However, to our knowledge, there is lack of information on the effects of the milk or MR allowance of dairy bull calves on the subsequent fattening and slaughter performance of bulls reared and finished for beef production.…”