Loading...
Please wait, while we are loading the content...
Similar Documents
Variantes genéticas de beta-lactoglobulina em vacas leiteiras e características físico-químicas e de composição do leite
| Content Provider | Semantic Scholar |
|---|---|
| Author | Botaro, Bruno Garcia |
| Copyright Year | 2007 |
| Abstract | BOTARO, B. G. Beta-lactoglobulin polymorphism in dairy cows and milk composition and physico-chemical characteristics. [Variantes genéticas de beta-lactoglobulina em vacas leiteiras e características físico-químicas e de composição do leite]. 2007. 74 f. Dissertação (Mestrado em Medicina Veterinária) – Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 2007. The objective of this study was to evaluate the association between beta-lactogobulin polymorphism and physico-chemical characteristics, composition (fat, total solids, urea, crude protein, true protein, non protein nitrogen and casein), and stability of milk. For this aim, 11 dairy herds were selected, six of them composed of crossbred Holstein-Zebu (H-Z) cows and five from Holstein cows. Milk samples were taken four times (twice in dry season and twice in rainy season), from 164 Holstein and 74 crossbred Holstein-Zebu cows. Individual milk samples were analyzed for milk composition and physico-chemical properties. For βlactoglobulin polymorphism analysis, blood samples were collected from each cow and then submitted to polymerase chain reaction (PCR) for genotype and allele frequencies determination. Heat stability of milk was determined by the alcohol-induced precipitation test, using the following ethanol concentrations 70, 76, 80 and 84oGL. The genotype frequencies were 0.28, 0.30 and 0.41 for AA, AB and BB, respectively. Allele B frequency was higher than A, 0.52 and 0.47, for Holstein cows, 0.58 and 0.41, for Holstein-Zebu, respectively. Genetic variants of β-lactoglobulin (AA, AB and BB) had no effect on physico-chemical and compositional characteristics, either among milk from Holstein cows, or from crossbred Holstein-Zebu. Breed effect was observed (Holstein and H-Z, respectively) on titrable acidity (16,16 and 17,07°D), pH (6,78 and 6,75), fat (3,31 and 3,20%), milk urea nitrogen (16,62 and 14,45mg/dL) and crude protein (3,13 and 3,04%) was observed. Effect of seasonality (rainy and dry season, respectively) was also observed on titrable acidity (16,62 and 16,34°D), pH (6,76 and 6,79) and freezing point (-0,5411 and -0,5376°H), lactose (4,34 and 4,50%), total solids (11,65 and 11,90%), LogCCS (2,44 and 2,34), crude protein (3,08 and 3,14%), true protein (2,84 and 2,91%), casein content (2,01 and 2,13%) and casein:true protein ratio (0,70 and 0,72). Effect of breed and seasonality on milk ethanol stability test was observed. The milk from Holstein-Zebu and from dry season was less stable than milk from Holstein cows and from rainy season. No effect of β-lactoglobulin polymorphism was observed on milk stability. |
| File Format | PDF HTM / HTML |
| DOI | 10.11606/D.10.2007.tde-04092007-082038 |
| Alternate Webpage(s) | https://teses.usp.br/teses/disponiveis/10/10135/tde-04092007-082038/publico/Bruno_Garcia_Botaro_sub.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Thesis |
