Seasonal grouping in a herd-year-season model of sire evaluation

Chauhan, V. P. S.; Hill, William G.

doi:10.1017/s000335610001833x

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…Since herd-year X month interaction is important (Chauhan and Hill, 1986), herd-year-month of calving is probably more appropriate effect for lactation traits. But for TD records, month of test is likely to be more important than month of calving due to environmental effects specific to the time of test.…”

Section: Methodsmentioning

confidence: 99%

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

1992

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Estimates 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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Section: Methodsmentioning

confidence: 99%

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

1992

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Section: 47mentioning

confidence: 99%

“…48 Histochemical studies of males of both lizards revealed that the lipid content and various enzymatic activities in the glandular tissues and/or secretions peak during the mating season. [49][50][51] An increase in enzyme activity associated with the citric acid cycle may reflect enhanced lipogenesis via acetyl CoA carboxylase. 51 The femoral gland secretions of males of the green iguana (Iguana iguana), a neotropical herbivorous iguanid, were found to contain FFAs and/or esterified fatty acids with chain lengths between C 14 and C 26 ; the steroids 3, epicoprostanol (4), 6, lanosterol (29), 33, 43, stigmasterol (46); and TLC components consistent with triacylglycerols, methyl esters, steryl esters, and phospholipids.…”

Section: Lizardsmentioning

confidence: 99%

Natural products from the integument of nonavian reptiles

2008

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“…Such biases between subclasses have been recognised in crop variety trials and models to overcome them have been proposed (W ilkinson , E ckert , H ancock and M ayo 1983). Using dairy cattle data, C hauhan and H ill (1986) reported significant covariances between cows calving in different months of a season within herd‐seasons. Subsequently, C hauhan and T hompson (1986) suggested the ‘rolling month’ sire model where the variance‐covariance matrix between months had unequal diagonal elements and non‐zero off‐diagonals.…”

Section: Introductionmentioning

confidence: 99%

Comparison of alternative methods of handling contemporary group effects in animal model prediction

Sivarajasingam¹

1993

J Animal Breeding Genetics

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Methods to associate animals between periods (grouping of records within a calving season into a 60-day interval starting from the date of the first calf born for 400-day weight analysis) within the contemporary group classification on sexmanagement group-date of weighing, using an animal model were compared. The data were derived from ten Angus herds. Assigning animals to more than one period and/or treating period as random or introducing days from start of calving period as a co-variate (linear and quadratic) did little to improve herd mean square error compared to the basic model where there were no associations between periods. The reduction in the standard errors of predictions were significant (p < 0.05) only when period within sex-management group-date of weighing was treated as random. However, the use of a similarity matrix S (which associates periods within the fixed contemporary group classification) in the mixed model equations reduced mean square error by as much as 7%. Using simulated observations for the ten herds, highest correlations between true breeding values and estimated breeding values were obtained only for the model using the similarity matrix. ZUSAMMENFASSUNG: Vergleich alternativer Methoden der Behandlung von Wirkungen kontemporärer Gruppen bei Tiermodellvoraussagen Methoden zur Verbindung zwischen Tieren verschiedener Perioden (Leistungsabschlüsse in 60-Tage-Intervallen einer Abkalbesaison für 400 Tagegewichte ab dem ersten geborenen Kalb) innerhalb kontemporärer Gruppenklassifikation und Geschlechts-Managementgruppen bei Tiermodellen wurden verglichen. Die Daten stammten von 10 Angusherden. Zuordnung von Tieren an mehr als eine Periode als zufällig oder Einbeziehung von Tagen von Beginn der Abkalbeperiode als Kovariable (linear und quadratisch) half wenig zur Verbesserung des Herdenfehlermittelquadrates im Vergleich zu dem Grundmodell, wo keine Verbindungen zwischen Perioden unterstellt wurden. Die Verminderung des Standardfehlers der Voraussage war signifikant (p < als 0,05) nur wenn Perioden innerhalb Geschlechts-Managementgruppen als zufällig betrachtet worden sind. Allerdings hat die Verwendung der Ähnlichkeitsmatrix S (welche Perioden innerhalb einer fixen kontemporären Gruppenklassifikation assoziiert) in der gemischten Modellgleichungen den Mittelquadratfehler um bis zu 7% reduziert. Unter Verwendung simulierter Beobachtungen für 10 Herden haben sich die höchsten Korrelationen zwischen wahren Zuchtwerten und geschätzten nur bei dem Modell ergeben, das die Ähnlichkeitsmatrix verwendet hat.

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Seasonal grouping in a herd-year-season model of sire evaluation

Cited by 9 publications

References 16 publications

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

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

Natural products from the integument of nonavian reptiles

Comparison of alternative methods of handling contemporary group effects in animal model prediction

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