BOLETÍN ELECTRÓNICO CIENTÍFICO
DEL NODO BRASILERO
DE INVESTIGADORES COLOMBIANOS
Número 2(Artículo 07), 2000
TÍTULO
Metabolic profile variations and reproduction performance in Holstein cows of different milk yields in Southern Brazil
TIPO: Trabajo publicado en Arq. Fac. Vet. UFRGS v.26, n.1: 53-64. 1998
AUTOR: Félix H. D. González felixgon@ufrgs.br and Jorge Antônio da Rocha
IDIOMA: Inglés
DIRECCIÓN PARA CONTACTO
Clinical Pathology Department, Faculty of Veterinary, Federal University of Rio Grande do Sul (UFRGS)
Av. Bento Gonçalves 9090. Porto Alegre - RS - Brazil. 91.540-000
PALABRAS CLAVE: Clinical Biochemistry, Reproductive Performance, Dairy Cows
RESUMEN
Variations in the components of blood chemistry could be indicative of metabolic or nutritional imbalances in dairy cattle. Production disorders, as lactation ketosis or imbalances in nitrogen metabolism could be detected through the profile analysis [1]. Metabolic imbalances are frequent in dairy cows of high production, usually as a consequence of feeding problems. Metabolic profiles could identify potential problems before they can be expressed as production losses or health and fertility disorders [2]. This work aims to study variations in the metabolic profile of Holstein cows under intensive husbandry with different levels of milk yield and to relate metabolic profile with reproductive performance. Blood samples for biochemical analysis were collected from 120 cows in 4 herds of Rio Grande do Sul State (Southern Brazil, latitude 30šS). Groups of animals included: high production cows (>9000 kg/lactation, n= 42), mild production cows (6000-7500 kg/lactation, n= 38) and pregnant dry cows (n= 40). Results showed that lactating cows had higher levels of cholesterol, total proteins, globulins and urea than dry cows. Urea levels in lactating cows were above reference interval (>42 mg/dl), and significantly higher than the mean obtained for dry cows (31.3 mg/dl). This changes should be associated with differentiated feeding management for lactating cows (confinement) and dry cows (grazing) [3]. The difference of milk production between two groups studied was significant (34.9 for high yield cows vs 23.4 kg/cow/day for mild yield cows). Higher production cows had higher concentrations of cholesterol, urea, albumin and aspartate transaminase (AST), and lower concentrations of glucose and calcium than mild production cows. It is reasonable to establish that plasma levels of cholesterol would be an indicator of the ability of the cow to produce milk, as a result of lipid mobilization from body reserves for lactogenesis [4]. Also, it is generally accepted that albumin levels are positively related with productive and reproductive performance [5]. The idea that glucose concentration can be diminished in blood of high milk yield cows [6], is reasserted by this study. In lactating cows it is common to observe hepatic injuries as a consequence of massive lipid mobilization, especially in high producing cows. In the present work, a higher level of AST was found in more productive cows, suggesting liver injuries. The high urea level found in more productive cows could indicate some degree of energetic deficiency or, more probably, an excess of nitrogen compounds [7] . The mean of days open was 122.7 for high production cows and 167.9 for mild production cows. Records of 49 cows were used to study the metabolic profile variations in relation to reproductive performance considering cows with less (n= 22) or more (n= 27) than 120 days open. Cows with more than 120 days open had higher levels of urea, AST and cholesterol and lower levels of proteins than cows with less than 120 days open. Collectively, the findings of the present study suggest that cows with poorer reproductive performance showed a metabolic profile compatible with an excess of ingested protein, as well as a restricted energy diet, which is leading to a moderate hepatic lesion, and to an impaired fertility.
BIBLIOGRAPHY
[1] PAYNE, J.M., PAYNE, S. The Metabolic Profile Test. Oxford University Press. 1987.
[2] KELLY, J.M. The use of metabolic profiles in dairy cows. Cattle Practice 18, 46-48. 1996
[3] JONES, G.M., WILDMAN, E.E., TROUTT, H.F. et al. Metabolic profiles in Virginia dairy herds of different milk yields. J. Dairy Sci. 65, 683-688. 1982.
[4] INGRAHAM, R.H., KAPPEL, L.C. Metabolic profile testing. Vet. Clin. N. Amer.: Food Anim. Pract. 4, 391-411. 1988.
[5] GONZALEZ, F.H.D., HAIDA, K., ZANELLA, R., FIGUR, K. Influência da época do ano no perfil metabólico em gado leiteiro no sul do Brasil. Arq. Fac. Vet. UFRGS 24, 11-24. 1996.
[6] SOMMER, H. Preventive Medicine in Dairy Cows. Vet. Med. Rev. 1, 42-63. 1975.
[7] MOORE, D.A., VARGA, G. BUN and MUN: urea nitrogen testing in dairy cattle. The Compendium - Food Animal 18(6): 712-720. 1996
BECNBIC,2(07)2000