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dc.contributor.author
Lacau, Isabel María
dc.contributor.author
Mejía, Miguel E.
dc.contributor.author
Becu, Damasia
dc.contributor.other
Di Alberto, P.
dc.contributor.other
Costa, C.
dc.date.available
2021-05-29T01:20:32Z
dc.date.issued
2009
dc.identifier.citation
Lacau, Isabel María; Mejía, Miguel E.; Becu, Damasia; Gastrointestinal nematode effects on grazing dairy herds during development and its impact on production; Nova Science Publishers, Inc.; 2009; 141-164
dc.identifier.isbn
978-1-60456-556-0
dc.identifier.uri
http://hdl.handle.net/11336/132804
dc.description.abstract
Most studies about the effects of gastrointestinal nematodes on bovines have been performed on beef herds, and relatively few trials have evaluated the effect of parasitism on dairy heifers and cows. We reviewed the results from our experiments in Holstein heifer calves grown on pastures, continuously treated with ivermectin from birth to puberty in comparison with naturally nematode infected untreated animals. Nematode eggs in feces of parasitized animals augmented rapidly during the 3rd and 4th months of life and then decreased, whereas treated animals remained egg-free throughout the same period. Treated animals grew faster than untreated ones and differences in body weight became significant in the 6th week of life. Parasite-free heifers reached puberty nearly four weeks earlier than infected ones. Besides, pelvic area at 39 weeks and at 15 months of age was greater in treated heifers when compared to parasitized animals. Age at first service was advanced by 10 weeks and age at calving by 3.5 months in treated versus untreated animals. Daily milk yield and fat content in milk during first lactation were similar in both groups but culling rate during first lactation was higher in untreated than in treated cows. Endocrine mechanisms involved in parasite action on growth, reproduction and production were investigated. Serum IGF-I levels increased from birth to 22 weeks of age and then reached a plateau in both groups, but levels were consistently higher in parasite-free heifers. Mean LH levels were diminished in untreated heifers 4 weeks before the first estrus and the amplitude of LH pulses were augmented in treated heifers when puberty was reached. Prolactin followed seasonal changes of sunlight duration and presented sporadic bursts in infected animals. These were related to high nematode infection and are probably involved in the immune response of the host. Furthermore, leptin which directly correlates with body weight during development showed a prepubertal surge two weeks before the first progesterone peak in both groups. We conclude that parasitism during growth in dairy heifers impairs full production as it delays onset of lactation and reduces productive life of the cows, and that those effects could be mainly ascribed to reduced IGF-1 levels during development.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Nova Science Publishers, Inc.
dc.rights
info:eu-repo/semantics/restrictedAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
DAIRY COW
dc.subject
PUBERTY
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REPRODUCTION
dc.subject
PARASITES
dc.subject.classification
Ciencias Veterinarias
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Ciencias Veterinarias
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CIENCIAS AGRÍCOLAS
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Producción Animal y Lechería
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Producción Animal y Lechería
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CIENCIAS AGRÍCOLAS
dc.title
Gastrointestinal nematode effects on grazing dairy herds during development and its impact on production
dc.type
info:eu-repo/semantics/publishedVersion
dc.type
info:eu-repo/semantics/bookPart
dc.type
info:ar-repo/semantics/parte de libro
dc.date.updated
2020-08-24T18:08:36Z
dc.journal.pagination
141-164
dc.journal.pais
Estados Unidos
dc.journal.ciudad
Hauppauge
dc.description.fil
Fil: Lacau, Isabel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina
dc.description.fil
Fil: Mejía, Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina
dc.description.fil
Fil: Becu, Damasia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.novapublishers.org/catalog/product_info.php?products_id=7175
dc.conicet.paginas
211
dc.source.titulo
New research on livestock science and dairy farming
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