Population parameter estimation of daily milk yield of the Chios sheep using test-day random regression models and Gibbs sampling

2005 ◽  
Vol 81 (2) ◽  
pp. 233-238 ◽  
Author(s):  
G. Banos ◽  
G. Arsenos ◽  
Z. Abas ◽  
Z. Basdagianni
Keyword(s):  
Gibbs Sampling ◽  
Milk Yield ◽  
Fourth Order ◽  
Regression Models ◽  
Post Partum ◽  
Random Regression ◽  
Population Parameter ◽  
Residual Variance ◽  
Daily Milk Yield ◽  
Daily Milk

AbstractParameters of daily milk yield during the first three lactations of Chios ewes were estimated with random regression models. Data consisted of 42 675 test-day records of 7121 ewes from 75 flocks that had lambed between 1998 and 2000. Models fitted fourth order fixed regressions on Legendre polynomials of the number of days post partum and fourth order random regressions on the individual animal. (Co)variance components were estimated with Gibbs sampling. Lactations were analysed separately. The four eigen values accounted for 0·80 to 0·84, 0·11 to 0·15, 0·04 to 0·05 and about 0·01 of the animal variance, respectively, depending on lactation number. Animal variance estimates, including genetic and, partly, permanent environment effects, were high at the beginning of each lactation and decreased as lactation progressed, suggesting that the animal effect is most important to early daily records. Residual variance was highest in the middle of lactation, suggesting that non-systematic environmental factors play a bigger at that time. Animal correlation estimates between daily yield records ranged from 0·26 to 0·99, were highest for adjacent days and decreased for days further apart. The decline had a different shape in the three lactations and was more evident in the first, suggesting that the three lactations may be biologically distinct traits. Animal correlation estimates between daily and total lactation milk yield ranged from 0·61 to 0·98 and were highest in the middle and lowest towards the end of lactation. Early lactation daily yield had an animal correlation of 0·70 to 0·80 with total lactation milk yield, in all three lactations. Results of this study suggest that daily milk yield records in the early stages of lactation may be useful for selection of ewes with high producing ability and accurate prediction of total lactation milk yield.

Genetic modelling of daily milk yield using orthogonal polynomials and parametric curves

2000 ◽  
Vol 70 (3) ◽  
pp. 407-415 ◽  
Author(s):  
S. Brotherstone ◽  
I. M. S. White ◽  
K. Meyer
Keyword(s):  
Orthogonal Polynomials ◽  
Milk Yield ◽  
Measurement Errors ◽  
Regression Models ◽  
Genetic Correlations ◽  
Random Regression ◽  
Parametric Curve ◽  
Parametric Curves ◽  
Daily Milk Yield ◽  
Daily Milk

AbstractRandom regression models have been advocated for the analysis of test day records in dairy cattle. The effectiveness of a random regression analysis depends on the function used to model the data. To investigate functions suitable for the analysis of daily milk yield, test day milk yields of 7860 first lactation Holstein Friesian cows were analysed using random regression models involving three types of curves. Each analysis fitted the same curve to model overall trends through a fixed regression and random deviations due to animals. Curves included orthogonal polynomials, fitted to order 3 (quadratic), 4 (cubic) and 5 (quartic), respectively, a three-parameter parametric curve and a five-parameter parametric curve. Sets of random regression coefficients were fitted to model both animals’ genetic effects and permanent environmental effects. Temporary measurement errors were assumed independently but heterogeneously distributed, and assigned to one of 12 classes. Results showed that the measurement error variances were generally lowest around peak lactation, and higher at the beginning and end of lactation. Parametric curves yielded the highest likelihoods, but produced negative genetic associations between yield in early lactation and later lactation yields, while positive genetic correlations across the entire lactation were estimated with all models involving orthogonal polynomials. The fit of models using orthogonal polynomials to model test day yield was improved by including higher order fixed regressions.

scholarly journals Reproductivity, Productivity and Management System of Indigenous Buffalo (Bubalus bubalis) Cows in Costal Areas of Pirojpur and Borguna District of Bangladesh

2014 ◽  
Vol 24 (1-2) ◽  
pp. 117-122 ◽  
Author(s):  
MR Karim ◽  
MZ Hossain ◽  
MR Islam ◽  
MS Parvin ◽  
MA Matin
Keyword(s):  
Birth Weight ◽  
Milk Yield ◽  
Management System ◽  
Post Partum ◽  
Bubalus Bubalis ◽  
Gestation Length ◽  
Calving Interval ◽  
Lactation Length ◽  
Daily Milk Yield ◽  
Daily Milk

Twenty five buffalo cows of Mothbaria Upazila of Pirojpur district and another twenty five indigenous buffalo cows of Pathorghata Upazila of Borguna district of Bangladesh were randomly selected and interviewed to collect data on reproductivity (gestation length, birth weight, age of first calving, post partum heat and calving interval), productivity (lactation length and daily milk yield) and management system (general management, housing, feeding, calf rearing and treatment facilities) of indigenous buffalo cows using pre-tested questionnaire during the period from January to June 2010. The reproductive parameters including gestation length, birth weight, age of first calving, post partum heat and calving interval of Mothbaria Upazila of Pirojpur district were 319.56 ± 5.93 days, 24.28 ± 4 kilograms, 50.88 ± 1.71 months, 153.6 ± 6.13 days, 547.92 ± 10.88 days respectively whereas in case of Pathorghata Upazila of Borguna district these parameters were 319.12 ± 4.69 days, 24.12 ± 3.6 kilograms, 51 ± 1.8 months, 153.44 ± 6.78 days, 547.24 ± 14.32 days respectively. The productive parameters including lactation length and daily milk yield of Mothbaria Upazila of Pirojpur district were 286.12 ± 11.27 days and 3.33 ± 0.68 liters/day respectively while in case of Pathorghata Upazila of Borguna district these parameters 290.44 ± 10.92 days and 3.43 ± 0.744 liters/day respectively. So, reproduction and production are almost regular comparing with other published reports with the exception of age of first calving which is almost 12 months later than the buffaloes of other countries. It could be concluded that the buffalo owners of these areas do not follow any scientific method of buffalo husbandry; they just follow traditional rearing system. The farmers mostly use buffaloes for draught purpose in these costal areas.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19113 Progress. Agric. 24(1&2): 117 - 122, 2013

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

2005 ◽  
Vol 73 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Shehadeh H Kaskous ◽  
Daniel Weiss ◽  
Yassin Massri ◽  
Al-Moutassem B Al-Daker ◽  
Ab-Dallah Nouh ◽  
...  
Keyword(s):  
Milk Yield ◽  
Post Partum ◽  
Lactation Performance ◽  
Machine Milking ◽  
Oxytocin Release ◽  
Daily Milk Yield ◽  
Daily Milk

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0·05) and daily milk yield until day 91 post partum was higher in PC than in WC (12·6±0·3 v. 7·1±0·4 kg, P<0·05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Effect of pre and post-natal nutrition on the performances of ewes and lambs under semi intensive rearing system

2020 ◽  
Vol 26 (1-2) ◽  
pp. 43-50
Author(s):  
S Ahmed ◽  
MRH Rakib ◽  
M Yesmin ◽  
M Ershaduzamman
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Milk Yield ◽  
Post Partum ◽  
Live Weight ◽  
Daily Weight Gain ◽  
Weaning Weight ◽  
Concentrate Mixture ◽  
Daily Milk Yield ◽  
Daily Milk

The study was conducted to know the effect of different levels of pre and post-natal nutrition on the performances of ewes and their lambs until 1 year of age and the profitable slaughter age of lambs under semi intensive system. Twenty eight (28) native Bengal ewes at 7 weeks of gestation were randomly assigned to four groups (T0, T1, T2, T3) and supplemented with a concentrate mixture at 0.0, 1.0, 1.5, 2.0% of their body weight respectively. Ewes were allowed to graze 8 hours daily. Creep mixture (20 g/lamb/day) was provided to lambs from 2 weeks age with an increment of 10 g/lamb/week. After weaning, 20 growing male lambs were selected and reared 01 year of age with concentrate mixture at 1.5% of their body weight and 8 hours grazing irrespective of treatment groups. Parameters like, ewe’s litter size, daily milk yield, post-partum heat and lamb’s birth weight, weaning weight, live weight at 06, 09 and 12 months were recorded. The data were analyzed in an ANOVA with CRD by using SPSS v. 20. The mean differences were tested by DMRT at a probability level of P<0.05. After weaning, the lamb growths were analyzed considering age as fixed factor. Regression correlations among different parameters with different ages were also performed. Significantly higher daily milk yield (P<0.01), weaning weight (P<0.05) and daily weight gain of lamb until weaning (P<0.05) were observed in T2 group. Besides, lambs weight at 06, 09, and 12 months differ significantly (P<0.01) along with corresponding daily weight gain (P<0.05). Lambs daily weight gain did not differ significantly from weaning to 09 months of age but significantly reduced (P<0.05) from 09 to 12months age. Finally, it may be concluded that a concentrate diet containing 20% CP during late pregnancy to lactation should be supplied to obtain maximum performances of ewes and their lambs. Besides, native Bengal lamb would be slaughtered between 06 to 09 months of age to get maximum return. Bang. J. Livs. Res. Vol. 26 (1&2), 2019: P. 43-50

scholarly journals Prediction of 305-day first lactation milk yield in cows with selected regression models

2003 ◽  
Vol 46 (3) ◽  
pp. 213-224 ◽  
Author(s):  
W. Grzesiak ◽  
J. Wojcik ◽  
B. Binerowska
Keyword(s):  
Milk Yield ◽  
Prediction Error ◽  
Regression Models ◽  
Production Costs ◽  
Spline Regression ◽  
Predictive Values ◽  
Coefficient Of Correlation ◽  
Daily Milk Yield ◽  
Daily Milk

Abstract. In the present study, the prognostic values of multiple and spline regression models were tested for 305-day lactation milk yield of cows. The predictors were: HF genes proportion in cow's genotype; average milk yield for 305-day lactation from 4 first milkings of all cows in a barn, in which a cow was used in a given year; month of calving; and average daily milk yield from first four test-day milkings. Models were developed basing on 628 first lactations of BW cows with average 71% HF genes proportion. Subsequently, the predictive values of the models examined were verified on the grounds of next 105 first lactations. Prognostic differences of the models examined were determined, finding the prognosis obtained with the spline regression more accurate (smaller prediction error, higher coefficient of correlation for prognosis and real values in the model containing information from first three test-day milkings). These models are easy to construct and may be useful in practical estimation of cow lactation yields. They may be used for predicting the actual lactation yield in order to minimise production costs and achieve better production results.

scholarly journals Genetic and environmental parameters estimation for milk traits in Slovenian dairy sheep using random regression model

2013 ◽  
Vol 58 (No. 3) ◽  
pp. 125-135 ◽  
Author(s):  
A. Komprej ◽  
Š. Malovrh ◽  
G. Gorjanc ◽  
D. Kon ◽  
M. Kovač
Keyword(s):  
Regression Model ◽  
Protein Content ◽  
Milk Yield ◽  
Random Regression ◽  
Dairy Sheep ◽  
Milk Traits ◽  
Random Regression Model ◽  
Lactation Curve ◽  
Daily Milk Yield ◽  
Daily Milk

(Co)variance components for daily milk yield, fat, and protein content in Slovenian dairy sheep were estimated with random regression model. Test-day records were collected by the ICAR A4 method. Analysis was done for 38 983 test-day records of 3068 ewes in 36 flocks. Common flock environment, additive genetic effect, permanent environment effect over lactations, and permanent environment effect within lactation were included into the random part of the model and modelled with Legendre polynomials on the standardized time scale of days in lactation. Estimation of (co)variance components was done with REML. The eigenvalues of covariance functions for random regression coefficients were calculated to quantify the sufficient order of Legendre polynomial for the (co)variance component estimation of milk traits. The existing 13 to 24% of additive genetic variability for the individual lactation curve indicated that the use of random regression model is justified for selection on the level and shape of lactation curve in dairy sheep. Four eigenvalues sufficiently explained variability during lactation in all three milk traits. Heritability estimate for daily milk yield was the highest in mid lactation (0.17) and lower in the early (0.11) and late (0.08) lactation. In fat content, the heritability was increasing throughout lactation (0.08&ndash;0.13). Values in protein content varied from the beginning toward mid lactation (0.15&ndash;0.19), while they rapidly increased at the end of lactation (0.28). Common flock environment explained the highest percentage of phenotypic variability: 27&ndash;41% in daily milk yield, 31&ndash;41% in fat content, and 41&ndash;49% in protein content. Variance ratios for the two permanent environment effects were the highest in daily milk yield (0.10&ndash;0.27), and lower in fat (0.04&ndash;0.08) and protein (0.01&ndash;0.10) contents. Additive genetic correlations during the selected test-days were high between the adjacent ones and they tended to decrease at the extremes of the lactation trajectory.

scholarly journals Conditioning Factors of Linearized Wood’s Function Lactation Curve Shape Parameters, Milk Yield, Fat and Protein Content in Murciano-Granadina Primiparous Does

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2115
Author(s):  
Juan Vicente Delgado Bermejo ◽  
Francisco Antonio Limón Pérez ◽  
Francisco Javier Navas González ◽  
Jose Manuel León Jurado ◽  
Javier Fernández Álvarez ◽  
...  
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Random Regression ◽  
Total Production ◽  
Curve Shape ◽  
Conditioning Factors ◽  
Lactation Length ◽  
Lactation Curve ◽  
Daily Milk Yield ◽  
Daily Milk

A total of 137,927 controls of 22,932 Murciano-Granadina first lactation goats (measured between 1996–2016) were evaluated to determine the influence of the number of kids, season, year and farm on total milk yield, daily milk yield, lactation length, total production of fat and protein and percentages of fat and protein. All factors analyzed had a significant effect on the variables studied, except for the influence of the number of kids on the percentages of fat and protein, where the variation was very small. Goats with two offspring produced nearly 15% more milk, fat and protein per lactation compared to goats with simple kids. Kiddings occurring in summer–autumn resulted in average milk, fat and protein yields nearly 14, 19 and 23% higher when compared to winter–spring kiddings. Lactation curves were evaluated to determine the effects of the number of kids and season, using the linearized version of the model of Wood in random regression analyses. Peak Yield increased by about 0.3 kg per additional offspring at kidding, but persistence was higher in goats with single offspring. The kidding season significantly influenced the lactation curve shape. Hence summer-kidding goats were more productive, and peak occurred earlier, while a higher persistence was observed in goats kidding during autumn.

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