Measurement of adaptive and innate immune function in calves raised under traditional and accelerated growth regimens
Date
2010-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
This study compared conventional and accelerated milk replacer feeding
regimens on growth, respiratory and digestive health, vaccination response, and
neutrophil mRNA levels. Holstein calves (10 male and 5 female) were randomly
assigned to a 10-week study on their second day of life. Treatments were control
(CON; n = 8) and accelerated (ACC; n = 7) milk replacer feeding programs. CON
calves were fed a 20% crude protein (CP) and 20% fat milk replacer (Advance Calvita
Supreme; Milk Specialities Global, Carpentersville, IL) at 1.25% birth body weight
daily from weeks 1 through 6 of life and 0.625% birth body weight daily during week
7. A 28.5% CP and 15% fat milk replacer (Advance Excelerate; Milk Specialities
Global, Carpentersville, IL) was fed to ACC calves at 1.5% birth body weight daily
during week 1, 2% current body weight daily from weeks 2 through 6, and 1% current
body weight daily during week 7. All calves were given milk replacer twice daily
during weeks 1 though 6, once daily during week 7, and were completely weaned
during week 8. Calf starter intake was measured daily through week 8. Body weight
and wither height were measured weekly. Fecal scores (1 = firm to 4 = liquid) and
respiratory scores (1 = normal; 2 = abnormal) were recorded twice daily. Neutrophils
were isolated from blood at weeks 1, 3, 5, and 8. Quantitative PCR was used to
measure neutrophil mRNA levels of 9 functionality genes: L-selectin, BPI, IL-1R1,
TNF-αR, TLR-2, TLR-4, SOD1, MPO, and NCF1. Adaptive immune function was
measured by vaccinating calves against ovalbumin at weeks 1, 3, and 5 and measuring
serum anti-ovalbumin IgG concentration at weeks 1, 3, 5, and 8. There was no treatment effect on wither height, respiratory score, or serum anti-ovalbumin IgG
concentration. Body weight during weeks 4 through 10 was greater for ACC than
CON calves (P < 0.01). Calf starter intake was greater for CON than ACC calves
during weeks 4 through 7 (P < 0.01), with no difference during week 8. CON calves
had firmer feces than ACC calves (fecal score 1.4 vs. 1.7, P = 0.02). Neutrophil Lselectin
mRNA levels were 51% greater in ACC than CON calves (P = 0.03). Feeding
calves a 28.5% CP and 15% fat milk replacer in an accelerated feeding regimen
increased growth and may enhance innate immune function, as indicated by the
increased neutrophil mRNA levels of L-selectin.