Relationship Between Days Open and Cumulative Milk Yield at Various Intervals from Parturition for High and Low Producing Cows

Oltenacu, P.A.; Rounsaville, T. R.; Milligan, Robert A.; Hintz, Raymond L.

doi:10.3168/jds.s0022-0302(80)83083-9

Cited by 62 publications

(34 citation statements)

References 11 publications

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“…However, elementary curves representing the effect of gestation on milk production showed that in fact the negative effect of pregnancy began at DCC 112, 131 and 132 for first-, second-and third-lactation cows, respectively. The results observed were in agreement with the stage of 100 to 150 days after conception reported by many authors (Oltenacu et al, 1980;Danell, 1982;Coulon et al, 1995). Similar to many other authors (Louca and Legates, 1968;Oltenacu et al, 1980;Coulon et al, 1995), we also observed that the effect of pregnancy was lower in primiparous than in multiparous cows.…”

Section: Discussionsupporting

confidence: 93%

“…The results observed were in agreement with the stage of 100 to 150 days after conception reported by many authors (Oltenacu et al, 1980;Danell, 1982;Coulon et al, 1995). Similar to many other authors (Louca and Legates, 1968;Oltenacu et al, 1980;Coulon et al, 1995), we also observed that the effect of pregnancy was lower in primiparous than in multiparous cows. The milk yield drop-off observed at DCC 230 ( Figure 4) was consistent with the 3.0 to 5.0 kg/day reported by Danell (1982) for Swedish Red and White and Swedish Friesian.…”

Section: Discussionsupporting

confidence: 93%

“…Environmental effects on lactation curves particular, from the second-third of pregnancy were considered to be responsible (Bauman and Currie, 1980;Oltenacu et al, 1980). Foetus growth might have an impact on rumen volume and distribution of nutrients between the foetus, milk synthesis and replenishment of energy reserves for the next lactation (Oltenacu et al, 1980).…”

Section: Discussionmentioning

confidence: 99%

“…Foetus growth might have an impact on rumen volume and distribution of nutrients between the foetus, milk synthesis and replenishment of energy reserves for the next lactation (Oltenacu et al, 1980). However, foetus growth essentially occurred during the last 2 months of pregnancy (Bauman and Currie, 1980), when cows were usually dried off.…”

Section: Discussionmentioning

confidence: 99%

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Environmental effects on lactation curves included in a test-day model genetic evaluation

Leclerc

Duclos²,

Barbat³

et al. 2008

Animal

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A large number of environmental factors affect the daily milk production of a cow. Lactation curves included in the French test-day model are modelled as a function of days in milk with semi-parametric curves (splines). The proper modelling of environmental effects in the test-day analysis was investigated using test-day records collected from the first three lactations of French Montbé liarde cows from 1988 to 2005. Four lactation-curve effects describing calving month, length of dry period, age at calving and gestation defined within parity-class were fitted. The shape of lactation curves did not depend on year of calving, which can be modelled as a constant over the whole lactation. To reduce computational requirements and time, data were pre-adjusted in a first step for fixed effects with no year interaction, and then used for genetic evaluation. Correlations for each lactation between 305-day estimates of genetic and permanent environment effects computed using pre-adjustment factors obtained at a 4-year interval were virtually one. The use of a two-step procedure had a very limited impact on the estimates of genetic and permanent environment effects. The minimum correlations with values estimated with a one-step procedure were 0.9984 and 0.9974, respectively. The knowledge of systematic environmental effects affecting the cow daily yield through lactation curves offers interesting perspectives to predict future daily milk production.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Environmental effects on lactation curves included in a test-day model genetic evaluation

Leclerc

Duclos²,

Barbat³

et al. 2008

Animal

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“…Contudo, a produção de leite deve ser ajustada para período de serviço somente se tiver efeito sobre a produção. Efeitos significativos foram relatados em vários trabalhos (OLTENACU et al, 1980;THOMPSON et al, 1982;FUNK et al, 1987;SADEK e FREEMAN, 1992;TEIXEIRA et al, 1999). TEIXEIRA et al (1999), utilizando modelo de touro, sugeriram fatores de ajustamento da produção de leite para período de serviço anterior e corrente e concluíram ser conveniente o ajustamento da produção de leite para período de serviço, ao se estimarem valores genéticos de touros.…”

Section: Introductionunclassified

Efeito do ajustamento da produção de leite para período de serviço anterior sobre os valores genéticos de bovinos da raça Holandesa

Teixeira

Ferreira²,

Freitas³

et al. 2001

R. Bras. Zootec.

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RESUMO -Registros de produção e reprodução de 6.877 lactações de 4.673 vacas foram usados para se determinar o efeito do ajustamento para período de serviço anterior em avaliações genéticas. Os valores genéticos previstos para produção de leite em kg foram calculados usando-se três modelos: Modelo 1 -sem correção para período de serviço, com os efeitos fixos de rebanho-ano-estação de parto, grupo genético (1-PO, 2-PC), idade ao parto como covariável até 2º grau e os efeitos aleatórios de animal, meio permanente e erro; Modelo 2 -mesmo anterior com a inclusão de período de serviço anterior; Modelo 3 -mesmo que o modelo 1, com as produções padronizadas para 100 dias de período de serviço anterior, por meio de fatores de ajustamento. Os valores genéticos previstos obtidos para cada modelo foram comparados. Vacas entre as 2% melhores apresentaram, em média, mudanças de nove e onze posições, respectivamente, quando os modelos 2 e 3 foram usados, comparadas com suas ordens obtidas com o modelo 1. Além disso, oito e onze vacas foram excluídas da relação das 2% melhores quanto aos seus valores genéticos para produção de leite, quando avaliadas, respectivamente, pelos modelos 2 e 3. As confiabilidades dos valores genéticos previstos obtidos usando-se os três modelos foram semelhantes. As correlações de ordem entre os valores genéticos estimados, tanto para vacas quanto para touros, para todos os modelos foram próximas de um. Portanto, o ajustamento para período de serviço anterior não alterou a ordem dos animais nesta avaliação genética na raça Holandesa no Estado de Minas Gerais.Palavras-chave: ajustamento, período de serviço, produção de leite, raça Holandesa Effect of Adjusting Production Records for Days Open on Breeding Values in HolsteinsABSTRACT -Production and breeding records from 6,877 lactations of 4,673 cows were used to evaluate the effect of adjusting for previous days open on genetic evaluations. Predicted breeding values for kg of milk were calculated using three animal models. Model 1 -contained no adjustment for days open and accounted for the fixed effects of herd-year-season, genetic group, age of calving (covariate) and the random effects of animal, permanent environment effect and error; Model 2 -same as one with previous days open included; Model 3 -production records were standardized to 100 days open before using model 1. Predicted breeding values from each model were compared. Cows in the 2% top had their ranks changed nine and 11 places for models 2 and 3, respectively, when compared to their rank from model 1. Furthermore, eight and 11 cows dropped from the top 2%, when evaluated with models 2 and 3, both accounted for days open. The reliabilities of the predicted breeding values for the three models were almost equal. The rank correlations between estimated breeding values for cows and sires for all models were near one. Therefore, adjustment for previous days open did not change the rank of animals in this genetic evaluation for Holsteins in the State of Minas Gerais. IntroduçãoNas avaliaçõ...

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Comparison of a prostaglandin-F2α-based reproductive program with an estrus detection-based reproductive program on a large commercial dairy herd

Slenning¹

1992

Theriogenology

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Relationship Between Days Open and Cumulative Milk Yield at Various Intervals from Parturition for High and Low Producing Cows

Cited by 62 publications

References 11 publications

Environmental effects on lactation curves included in a test-day model genetic evaluation

Environmental effects on lactation curves included in a test-day model genetic evaluation

Efeito do ajustamento da produção de leite para período de serviço anterior sobre os valores genéticos de bovinos da raça Holandesa

Comparison of a prostaglandin-F2α-based reproductive program with an estrus detection-based reproductive program on a large commercial dairy herd

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