Variantes genéticas de kappa-caseína em vacas leiteiras e características físico-químicas e de composição do leite

Content Provider	Semantic Scholar
Author	Lima, Ygor Vinicius Real De
Copyright Year	2005
Abstract	LIMA, Y. V. R. de. Kappa-casein polimorphism in dairy cows and, physico-chemical properties and composition of milk. [Variantes genéticas de kappa-caseína em vacas leiteiras e características físico-químicas e de composição do leite]. 2005. 84 f. Dissertação (Mestrado em Medicina Veterinária) Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Pirassununga, 2005. The objective of this study were to determine the effects of kappa-casein gene polymorphisms, breed and season on physical-chemical properties (acidity, pH and cryoscopy), composition (fat, lactose, total solids, somatic cells count, urea, crude protein, true protein, non protein nitrogen and non casein nitrogen) and stability of milk. For this aim 11 dairy herds were selected, six of them composed of Girolando cows and five from Holstein cows, in average milk samples were taken of 112 cows from each herd, collected three times: twice in dry season and once on rainy season. Each cow were analyzed for milk composition, physico-chemical properties, and to determine its kappa-casein polymorphism. This study was divided in two, the first one analyzed possible breed and season effects over milk physicochemical characteristics, composition and stability. Breed effect was observed over acidity, pH, lactose, urea and milk stability. Season effects was significant for pH, cryoscopy, lactose, urea, CP, total solids, SCC, TP, casein, EqNPN and heat milk stability. In cows Girolando it was observed highest total solids in dry season. Milk cryoscopy had season effects only on Holstein cows, with highest results in dry season. Lactose concentration was greatest in Holstein cow in dry season. Urea concentration showed breed and season effect on this study. Crude protein was affected by breed and season, in dry season the concentration were highest for Holstein and Girolanda. Casein milk concentration demonstrated season effect. Heat milk stability showed breed stability, milk from Holstein cow were more stable that milk from Girolanda cows. Season is a determinant factor for milk stability, milk showed more stable in rainy season than during dry period. The second study analyzed: kappa-casein gene polymorphisms in Holstein and Girolando cows and its effects over milk physico-chemical characteristics, milk composition and milk heat stability. Kappa-casein allele A had a higher frequency, than allele B, in Girolando and Holstein cows in comparison with other polymorphisms. No effect of kappa-casein polymorphism was observed on milk phisicochemical characteristics and on milk fat, total solids, lactose, SCC, and milk urea. There were no difference for milk protein composition (EqNPN, NCNC, TP, casein and EqNCN) for kappa-casein polymorphism. Milk alcohol stability did not showed effect of gene polymorphism.
File Format	PDF HTM / HTML
DOI	10.11606/D.10.2005.tde-18092006-104611
Alternate Webpage(s)	https://teses.usp.br/teses/disponiveis/10/10135/tde-18092006-104611/publico/YgorViniciusReadeLima.pdf
Alternate Webpage(s)	https://doi.org/10.11606/D.10.2005.tde-18092006-104611
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article