Factors affecting the shape of the lactation curve in cattle

Wood, P. D. P.

doi:10.1017/s0003356100026945

Cited by 153 publications

(95 citation statements)

References 6 publications

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“…As a result, although only morning milk yield which is higher than evening milk yields (Quist et al, 2008) was evaluated, the estimated shape of lactation curves during the first 20 weeks of lactation were consistent with those reported by numerous previous studies (e.g. Wood, 1969;Walsh et al, 2007). Decline of milk protein and milk fat concen- tration during the first two months after parturition followed by a respective increase of values is in agreement with findings of Friggens et al (2007).…”

Section: Milk Yield and Milk Compositionsupporting

confidence: 89%

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

Sigl¹,

Meyer²,

Wiedemann³

2012

CZECH J ANIM SCI

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ABSTRACT:The objective of the present study was to refine a previously developed method to isolate primary bovine mammary epithelial cells (pBMEC) from fresh milk. Using this method, it was tested whether the number of pBMEC and the relation of recovered pBMEC to total somatic cell count vary within the individual lactation stages. Furthermore, the expression levels of the milk protein genes during the first twenty weeks of lactation were determined by quantitative PCR method. A total number of 152 morning milk samples were obtained from twenty-four Holstein-Friesian cows during the first 20 weeks of lactation (day 8, 15, 26, 43, 57, 113, and 141 postpartum). Numbers of extracted pBMEC were consistent at all time-points (1.1 ± 0.06 to 1.4 ± 0.03 ×10 3 /ml) and an average value of RNA integrity number (RIN) was 6.3 ± 0.3. Percentage of pBMEC in relation to total milk cells (2.0 ± 0.2 to 6.7 ± 1.0%) correlated with milk yield. Expression patterns of the casein genes alpha (α) S1 , (α) S2 , beta (β), and kappa (κ) (CSN1S1, CSN1S2, CSN2, CSN3, respectively) and the whey protein genes α-lactalbumin (LALBA) and progestagen-associated endometrial protein (PAEP; known as β-lactoglobulin) were shown to be comparable, i.e. transcripts of all six milk protein genes were found to peak during the first two weeks of lactation and to decline continuously towards mid lactation. However, mRNA levels were different among genes with CSN3 showing the highest and LALBA the lowest abundance. We hypothesized that milk protein gene expression has a pivotal effect on milk protein composition with no influence on milk protein concentration. This paper is the first to describe milk protein gene expression during lactation in pBMEC collected in milk. Future studies will be needed to understand molecular mechanisms in pBMEC including regulation of expression and translation throughout lactation.

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Section: Milk Yield and Milk Compositionsupporting

confidence: 89%

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

Sigl¹,

Meyer²,

Wiedemann³

2012

CZECH J ANIM SCI

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“…As reported by many authors (Wood, 1969;Danell, 1982;Wilmink, 1987b;Pé rochon et al, 1996), this study showed that daily yield was strongly affected by environmental factors such as region, year, parity, month of calving, age at calving, length of dry period before calving and pregnancy. In the 1980s, the objectives of most studies were to develop additive or multiplicative adjustment factors for lactation yield.…”

Section: Discussionsupporting

confidence: 73%

“…Calving month effect Many authors mentioned calving month as an effect with considerable influence on the cow's milk production (Wood, 1969;Danell, 1982;Wilmink, 1987b;Ptak et al, 1993). In this study, the effect of calving month was found to be significant on daily milk yield (Table 3).…”

Section: Discussionmentioning

confidence: 57%

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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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“…Diversos estudos têm sido feitos em bovinos (WOOD, 1967(WOOD, , 1969(WOOD, , 1974, utilizando equações que possibilitem representar a curva de lactação com precisão.…”

Section: Introductionunclassified

Estudo de efeitos ambientais que influem na forma da curva de lactação de cabras mestiças no estado da Paraíba

Ribeiro

Filho

1999

R. Bras. Zootec.

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RESUMO -O objetivo deste experimento foi estudar a influência de efeitos ambientais sobre a forma da curva de lactação (produção no pico, tempo de pico e persistência) de cabras mestiças Alpina x Gurguéia, ajustada pela função gama incompleta. Dados de 6126 controles, referentes a 877 lactações de 366 cabras criadas na Fazenda Carnaúba, localizada no município de Taperoá, Estado da Paraíba, no período de 1988 a 1995, foram usados. A função foi ajustada por regressão linear, após transformação logarítmica, e pelo método iterativo não-linear. Os parâmetros obtidos por regressão linear tiveram coeficiente de determinação ajustado ( 2 a R ) de 71% versus 2 a R de 90% obtido para a regressão não-linear. Produção máxima, tempo de pico e produção no pico foram obtidos por intermédio da função ajustada por regressão não-linear, que apresentou ajuste superior. O estudo dos efeitos ambientais sobre estas características foi realizado pelo método dos quadrados mínimos, usando um modelo contendo os efeitos de tipo de parto, ordem de parto, ano do parto e estação de parto. Os efeitos ambientes influenciaram todas as características estudadas. Maiores picos de produção foram observados para as cabras adultas, o que foi justificado pelo completo desenvolvimento fisiológico dos animais.Palavras-chave: curva de lactação, cabras, função gama incompleta Study of the Environmental Effects that Affect the Shape of Lactation Curves of Crossbred Goats in Paraíba StateABSTRACT -The objective of this experiment was to study the effect of environmental factors on the shape of lactation curves (peak yield, time of peak and persistency) of crossbred Alpine x Gurguéia goats fitted by Incomplete gamma function. Data from 6126 records of 877 lactation of 366 goats raised on Carnaúba Farm, Taperoá city, Paraíba State in the period from 1988 to 1995 were used. The function was fitted by linear regression, after logarithmic transformation and by non-linear iterative method. Adjusted coefficient of determination ( 2 a R ) for linear regression was 71% versus a 2 a R of 90% obtained by non-linear regression. Peak yield, time of peak and persistency were obtained by fitting the non-linear regression, that showed superior fit. The study of environmental effects on those traits was made by least squares method, including in the model the following factors: calving type, calving order, calving year and calving season. The environmental effects affected all the studied traits. Higher milk peak yields were observed for adult goats, which was justified by the complete physiological development of these animals.

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Factors affecting the shape of the lactation curve in cattle

Cited by 153 publications

References 6 publications

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

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

Estudo de efeitos ambientais que influem na forma da curva de lactação de cabras mestiças no estado da Paraíba

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