Genetic and environmental effects on milk yield of Pitangueiras cattle

ABSTRACTData from 5270 lactation records of 1380 cows sired by 132 bulls and recorded from 1962 to 1977 were analysed. Statistical analyses, using least squares and maximum likelihood methods, showed significant effects for genetic group, age of cow, month and year of calving, and lactation length. Overall mean milk yield was 2780 kg (CV = 0·31) with mean lactation length of 281 days. Maximum production occurred in the fifth lactation (104 or 105 months of age at calving) with a yield of 1·3 times that of the first lactation. Repeatability estimated by intraclass correlation was 0·40 (s.e. 0·03). Heritability estimated from paternal half-sib correlation was 0·16 (s.e. 0·06). Overall results were very similar to those obtained from research with European breeds in temperate areas.

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A comparison of least squares and maximum likelihood methods using sine fitting in ADC testing

Measurement ◽

10.1016/j.measurement.2013.05.004 ◽

2013 ◽

Vol 46 (10) ◽

pp. 4362-4368 ◽

Cited By ~ 11

Author(s):

Ján Šaliga ◽

István Kollár ◽

Linus Michaeli ◽

Ján Buša ◽

Jozef Lipták ◽

...

Keyword(s):

Maximum Likelihood ◽

Least Squares ◽

Likelihood Methods ◽

Maximum Likelihood Methods ◽

Fitting In ◽

Adc Testing

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Least Squares/Maximum Likelihood Methods for the Decision-Aided GFSK Receiver

IEEE Signal Processing Letters ◽

10.1109/lsp.2009.2016832 ◽

2009 ◽

Vol 16 (6) ◽

pp. 517-520 ◽

Cited By ~ 4

Author(s):

Dah-Chung Chang

Keyword(s):

Maximum Likelihood ◽

Least Squares ◽

Likelihood Methods ◽

Maximum Likelihood Methods

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Genetic parameters of test day records of British Holstein-Friesian heifers

Animal Science ◽

10.1017/s0003356100037211 ◽

1992 ◽

Vol 55 (1) ◽

pp. 11-21 ◽

Cited By ~ 64

Author(s):

B. L. Pander ◽

W. G. Hill ◽

R. Thompson

Keyword(s):

Maximum Likelihood ◽

Milk Yield ◽

Milk Fat ◽

Genetic Parameters ◽

Genetic Correlations ◽

Lactation Performance ◽

Likelihood Methods ◽

Holstein Friesian ◽

Maximum Likelihood Methods ◽

Heritability Estimates

AbstractEstimates of genetic parameters for test day records of yields of milk, fat and protein and concentrations of fat and protein were obtained on 47 736 British Holstein-Friesian heifers in 7973 herds, progeny of 40 proven (to improve connectedness) and 707 young sires (comprising about one-fifth of the progeny), using multivariate restricted maximum likelihood methods with a sire model.Heritability estimates for lactation yields of milk, fat and protein and concentrations of fat and protein were 0·49, 0·39, 0·43, 0·63 and 0·47, respectively. Estimates for individual test day records of these traits ranged from 0·27 to 0·43, 0·16 to 0·34, 0·22 to 0·33, 0·11 to 0·48 and 0·21 to 0·43, respectively. Generally, heritability estimates for test day records were lowest at start and highest in mid lactation.Estimates of genetic correlations among yields of a trait on different test days ranged from 0·57 to 0·99, and for fat and protein concentrations from 0·34 to 0·99, the correlations being highest for adjacent tests. Phenotypic correlations were lower than genetic correlations. Genetic correlations of test day records with corresponding lactation traits were high (0·76 to 0·99), being highest in mid lactation.Genetic correlations of test day milk yield with test day yields and concentrations of fat and protein throughout the lactation were similar to those for complete lactation.The high heritabilities of test day yields and their high genetic correlations with complete lactation, except for the first 1 or 2 test days, suggest that lactation performance may be predicted from test days in early and mid lactation.

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