The effects of dry period length and dietary energy source on natural antibody titers and mammary health in dairy cows.
In earlier studies, natural antibodies (NAb) were related not only to the energy balance (EB) of dairy cows, but also to somatic cell count (SCC) and clinical mastitis (CM). The first objective of our study was to evaluate the effects of dry period length and dietary energy source on titers of NAb binding keyhole limpet hemocyanin (KLH) and lipopolysaccharide (LPS) in plasma and milk, SCC and CM occurrence in dairy cows in two subsequent lactations. Our second objective was to study the relationship between NAb levels and mammary health. Holstein-Friesian dairy cows (N=167) were randomly assigned to three dry period lengths (0, 30 or 60-d) and two early lactation rations (glucogenic or lipogenic). Treatments were repeated during two subsequent lactations (years 1 and 2). In year 2, 19 cows which were planned to have 0-d dry period dried off naturally and were assigned to an additional group 0→30-d dry period. In year 1, cows with a 0-d dry period had a higher SCC, a higher titer of immunoglobulin G (IgG) binding LPS in plasma, and higher titers of IgG and IgM binding KLH and LPS in milk compared with cows with a 30-d or 60-d dry period. In year 2, cows with a 60-d dry period had a lower SCC than cows with a 30-d and 0→30-d dry periods. In year 2, dry period length did not affect NAb titers in plasma or milk. The CM occurrence was 17 percent in year 1 of the experiment and 25 percent in year 2, and did not differ according to dry period lengths or rations. For both years, an increasing titer of IgG binding LPS in plasma was associated with decreased odds of a high SCC and decreased odds of CM occurrence. Also up to three weeks before the CM occurrence, an increasing titer of IgM binding KLH and LPS in plasma was associated with a decreased odds of CM occurrence. In conclusion, omitting the dry period increased SCC, NAb titers in milk and IgG binding LPS in plasma compared with a short (30-d) or conventional (60-d) dry period. The effects on NAb titers, however, were only present in the first year after omitting the dry period and disappeared after repeated omitting the dry period. Moreover, an increasing titer of IgG binding LPS in plasma was associated with decreased odds of high SCC and CM occurrence.
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands; Faculty of Animal Husbandry, Universitas Padjadjaran, 45363 Bandung, Indonesia. Electronic address: novim001@gmail.com.
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Mayasari
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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Rijks
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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de Vries Reilingh
Livestock Research, Wageningen University and Research Centre, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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GJ
Remmelink
Animal Breeding and Genomics Centre, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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Ducro
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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Kemp
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands.
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Parmentier
Adaptation Physiology Group, Department of Animal Science, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands. Electronic address: vanknegsel@wur.nl.
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Van Knegsel
D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D003612:Dairying; D004734:Energy Metabolism / Q000187:drug effects; D006433:Hemocyanins / Q000494:pharmacology; D007774:Lactation; D008070:Lipopolysaccharides / Q000097:blood / Q000494:pharmacology; D008414:Mastitis, Bovine / Q000276:immunology*; D008892:Milk / Q000737:chemistry*; D011897:Random Allocation; D013997:Time Factors
D008070:Lipopolysaccharides; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin
Clinical mastitis; Continuous milking; Nutrition; Somatic cell count