scholarly journals Estimation of (co)variance components across breeds by a test-day model adapted to New Zealand dairy cattle

2005 ◽  
Vol 2005 ◽  
pp. 114-114
Author(s):  
S. Vanderick ◽  
B. Harris ◽  
P. Mayeres ◽  
A. Gillon ◽  
C. Croquet ◽  
...  
Keyword(s):  
New Zealand ◽  
Dairy Cattle ◽  
Variance Components ◽  
Dairy Farmers ◽  
Breeding Values ◽  
Dairy Heifers ◽  
Breed Differences ◽  
Genetic Contributions

In New Zealand, crossbreeding is largely used by dairy farmers. Currently an important proportion of cows are crossbreds, mostly Holstein-Friesians (HF) x Jersey (JE). Crossbred bulls are currently being progeny tested in New Zealand. Actually, more than one third of the replacement dairy heifers are crossbred animals (Montgomerie, 2002). However currently available methods to model genetic contributions of purebreds to crossbreds take breed differences only partly into account and therefore do not permit an optimal use of crossbred data. The first objective of our study was to allow the modelling of different additive breeding values according to parental breeds to define overall additive breeding values as a function of breed composition.

scholarly journals Estimated variance components and breeding values for pre-weaning growth criteria in Romney sheep

2017 ◽  
Vol 21 (2) ◽  
pp. 73
Author(s):  
Eslam Faid-Allah ◽  
E. Ghoneim ◽  
A.H.M. Ibrahim
Keyword(s):  
New Zealand ◽  
Variance Components ◽  
Genetic Factors ◽  
Gene Marker ◽  
Breeding Values ◽  
Factors Affecting ◽  
Kleiber Ratio ◽  
Body Weights ◽  
Estimated Breeding Values ◽  
Positive Coefficients

<p class="abstrak2">This study was carried out to investigate variance components, direct heritability, maternal genetic parameters, estimated breeding values and factors affecting pre-weaning growth criteria of Romney sheep. Data were collected over the period from 2006 to 2012 with records of 4989 lambs descended from 76 rams and 2190 ewes of Romney sheep maintained at S. Island of New Zealand via Gene Marker Lab., Faculty of Agric. and Life Sci., Lincoln Univ., New Zealand. Results proved that genetic and non-genetic factors affecting studied criteria had significant effects (P&lt;0.05). Genetic and environmental estimates of live body weights at birth (LBW), weaning (LWW) and Kleiber ratio (KR) were 0.20±0.074, 0.15±0.042 and 0.14±0.052 for direct heritability (h<sup>2</sup>a±SE); 0.59±0.219, 0.41±0.023 and 0.08±0.002 for maternal heritability (h<sup>2</sup>m±SE); 0.11684, 2.6378 and 0.27565 for additive variances (σ<sup>2</sup>a), 0.34596, 7.1179 and 0.14532 for maternal variances (σ<sup>2</sup>m); and 0.002395, 10.1262 and 0.509339 for permanent environmental variances (σ<sup>2</sup>e), respectively. EBV’s of LBW, LWW and KR ranged from -0.555: 0.502, -1.554: 3.006 and -0.633: 0.242 direct, -0.863: 0.954, -4.942: 2.554 and -0.469: 0.179 maternal for rams, respectively; and -0.664: 0.830, -2.996: 4.586 and -1.651: 0.677 direct, 1.429: 1.142, -7.541: 4.920 and -1.223: 0.492 maternal for ewes, respectively. Results suggest the importance of considering the non-genetic factors in pre-weaning growth performance of lambs. Moderate heritability and positive coefficients of phenotypic and genetic correlation for studied criteria indicate to the possibility of improving them using traditional selection.</p>

Genetic correlations between 305-day and monthly test day milk yield records in primiparous Iranian Holsteins

2001 ◽  
Vol 2001 ◽  
pp. 219-219
Author(s):  
H. Farhangfar ◽  
P. Rowlinson ◽  
M.B. Willis
Keyword(s):  
Dairy Cattle ◽  
Genetic Gain ◽  
Genetic Correlations ◽  
Cattle Breeding ◽  
Breeding Values ◽  
Dairy Heifers ◽  
The Past ◽  
Dairy Cattle Breeding ◽  
Adjustment Factors ◽  
Breeding Programmes

Traditionally, in most dairy cattle breeding programmes genetic evaluation of dairy sires and cows has been primarily based on 305-day lactation yield. To provide 305-day lactation yields many partial lactations have to be extended by adjustment factors resulting in overestimation or underestimation of 305-day yields which in turn leads to biased prediction of breeding values. Over the past decade there has been a considerable interest in using monthly test day records instead of 305-day lactation yield to predict breeding values of dairy cattle as early as possible and also to increase genetic gain through reducing generation interval. The main objective of present research was to estimate the genetic correlations between 305-day and monthly test day milk yields in Iranian Holstein dairy heifers.

scholarly journals Estimation of (co)variance components and breeding values for test-day milk production traits of Holstein dairy cattle via Bayesian approach

2014 ◽  
Vol 30 (1) ◽  
pp. 15-28 ◽  
Author(s):  
R. Mosharraf ◽  
J. Shodja ◽  
M. Bohlouli ◽  
S. Alijani ◽  
S.A. Rafat
Keyword(s):  
Dairy Cattle ◽  
Regression Model ◽  
Milk Production ◽  
Milk Fat ◽  
Variance Components ◽  
Random Regression ◽  
Production Traits ◽  
Milk Production Traits ◽  
Breeding Values ◽  
Random Regression Model

Genetic parameters of milk, fat, and protein yields were estimated in the first lactation of Holstein dairy cattle. The records were collected during the period 2006 to 2011 and analyzed fitting the random regression model. The data included 41178, 25397 and 18716 test-day records of milk, fat and protein yields, respectively that produced by 4746, 3437 and 2525 cows respectively. Fixed effects in model included herd-year-month of test day and age-season of calving. The fixed and random regressions were modeled with normalized Legendre polynomials and (co)variance components were estimated by Bayesian method and Gibbs sampling was used to obtain posterior distributions. Estimates of heritability for milk, fat and protein yields ranged from 0.18 to 0.26; 0.06 to 0.11 and 0.09 to 0.22, respectively. Heritabilities for 305-d milk, fat and protein yields were 0.36, 0.23 and 0.29, respectively. For milk and protein yields, heritabilities were lower at the early of lactation due to the trends of lower additive genetic variance, higher permanent environmental variance. Genetic correlations for milk, fat and protein yields ranged from 0.14 to 1.00; 0.39 to 1.00 and 0.27 to 1.00, respectively. Ranges of estimated breeding values for 305-d yield of milk, fat and protein yields were from -1194.48 to 1412.44; -210.57 to 271.22 and -194.08 to 203.25, respectively. According to the results of this study, random regression model seems to be a flexible and reliable procedure for the genetic evaluation of milk production traits and it can be useful in the breeding programs for Iranian dairy cattle.

scholarly journals Estimation of test-day model (co)variance components across breeds using New Zealand dairy cattle data

2009 ◽  
Vol 92 (3) ◽  
pp. 1240-1252 ◽  
Author(s):  
S. Vanderick ◽  
B.L. Harris ◽  
J.E. Pryce ◽  
N. Gengler
Keyword(s):  
New Zealand ◽  
Dairy Cattle ◽  
Variance Components

Use of molecular technologies for the advancement of animal breeding: genomic selection in dairy cattle populations in Australia, Ireland and New Zealand

2013 ◽  
Vol 53 (9) ◽  
pp. 869 ◽  
Author(s):  
Richard J. Spelman ◽  
Ben J. Hayes ◽  
Donagh P. Berry
Keyword(s):  
New Zealand ◽  
Dairy Cattle ◽  
Evaluation System ◽  
Test Results ◽  
Genomic Information ◽  
Breeding Programs ◽  
Breeding Values ◽  
Genetic Evaluations ◽  
Initial Results ◽  
Genomic Predictions

The New Zealand, Australian and Irish dairy industries have used genomic information to enhance their genetic evaluations over the last 2–4 years. The improvement in the accuracy obtained from including genomic information on thousands of animals in the national evaluation system has revolutionised the dairy breeding programs in the three countries. The genomically enhanced breeding values (GEBV) of young bulls are more reliable than breeding values based on parent average, thus allowing the young bulls to be reliably selected and used in the national herd. Traditionally, the use of young bulls was limited and bulls were not used extensively until they were 5 years old when the more reliable progeny test results became available. Using young sires, as opposed to progeny-tested sires, in the breeding program dramatically reduces the generation interval, thereby facilitating an increase in the rate of genetic gain by 40–50%. Young sires have been marketed on their GEBV in the three countries over the last 2–4 years. Initial results show that the genomic estimates were overestimated in both New Zealand and Ireland. Adjustments have since been introduced into their respective national evaluations to reduce the bias. A bias adjustment has been included in the Australian evaluation since it began; however, official genomic evaluations have not been in place as long as in New Zealand and Ireland, so there has been less opportunity to validate if the correction accounts for all bias. Sequencing of the dairy cattle population has commenced in an effort to further improve the genomic predictions and also to detect causative mutations that underlie traits of economic performance.

Adoption and Commercialization of Green Corn, Green Corn –Based Silage, Haylage and Ummb Production for Dairy Cattle in Cagayan Valley, Philippines

2019 ◽  
Vol 4 (4) ◽  
pp. 82-92
Author(s):  
Eva U. Cammayo ◽  
Nilo E. Padilla
Keyword(s):  
Dairy Cattle ◽  
Nutritive Value ◽  
Crop Residues ◽  
Smallholder Farmers ◽  
Corn Silage ◽  
Small Scale ◽  
Dairy Farmers ◽  
Feed Resources ◽  
Dry Spell ◽  
Dairy Animals

This research aimed to improve dairy production and increase the income of dairy farmers using locally available feed resources. Small-scale milk producers rely heavily on available feed resources in the locality which are either indigenous in the area or introduced species for feed and nutrition of their dairy cattle and buffalos. Their milk output depends mainly on seasonal fluctuations in the quality and quantity of natural forage. Crop residues such as corn stover and rice straw which are high in fiber but low in nutrients serve as a feed supplement and filler to the daily diets of dairy cattle and buffalos. Cagayan Valley is an ear of top corn and rice-producing region. The potential of crop residues as feed supplements or raw materials of dairy cattle/buffalo feed mix is great. But dairy farmers still face the scarcity problem of quality feed resources for dairy animals especially during the dry season. The supply of forage is very low during the dry spell. Inadequate feed mix and low nutritive value of feed mix result in low or no milk production. Producing green corn and ensiling it to produce green corn silage preserves and prolong the storage life of forages. In this way, a stable supply of feed mix for dairy animals is assured year-round. Type of Paper: Empirical. Keywords: adoption and commercialization, dairy industry, financial viability, green-corn silage production, indigenous grasses, smallholder farmers.

Influence on the implementation of biosecurity measures in dairy cattle farms: Communication between veterinarians and dairy farmers

2021 ◽  
Vol 190 ◽  
pp. 105329
Author(s):  
Sebastián Moya ◽  
Kin Wing (Ray) Chan ◽  
Stephen Hinchliffe ◽  
Henry Buller ◽  
Josep Espluga ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Dairy Farmers ◽  
Cattle Farms

scholarly journals Additive genetic variance and covariance between relatives in synthetic wheat crosses with variable parental ploidy levels

Genetics ◽  
2021 ◽  
Vol 217 (2) ◽  
Author(s):  
L E Puhl ◽  
J Crossa ◽  
S Munilla ◽  
P Pérez-Rodríguez ◽  
R J C Cantet
Keyword(s):  
Hexaploid Wheat ◽  
Variance Components ◽  
Bayesian Model ◽  
Synthetic Hexaploid Wheat ◽  
Data Sets ◽  
Hierarchical Bayesian Model ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Values ◽  
Synthetic Hexaploid

Abstract Cultivated bread wheat (Triticum aestivum L.) is an allohexaploid species resulting from the natural hybridization and chromosome doubling of allotetraploid durum wheat (T. turgidum) and a diploid goatgrass Aegilops tauschii Coss (Ae. tauschii). Synthetic hexaploid wheat (SHW) was developed through the interspecific hybridization of Ae. tauschii and T. turgidum, and then crossed to T. aestivum to produce synthetic hexaploid wheat derivatives (SHWDs). Owing to this founding variability, one may infer that the genetic variances of native wild populations vs improved wheat may vary due to their differential origin and evolutionary history. In this study, we partitioned the additive variance of SHW and SHWD with respect to their breed origin by fitting a hierarchical Bayesian model with heterogeneous covariance structure for breeding values to estimate variance components for each breed category, and segregation variance. Two data sets were used to test the proposed hierarchical Bayesian model, one from a multi-year multi-location field trial of SHWD and the other comprising the two species of SHW. For the SHWD, the Bayesian estimates of additive variances of grain yield from each breed category were similar for T. turgidum and Ae. tauschii, but smaller for T. aestivum. Segregation variances between Ae. tauschii—T. aestivum and T. turgidum—T. aestivum populations explained a sizable proportion of the phenotypic variance. Bayesian additive variance components and the Best Linear Unbiased Predictors (BLUPs) estimated by two well-known software programs were similar for multi-breed origin and for the sum of the breeding values by origin for both data sets. Our results support the suitability of models with heterogeneous additive genetic variances to predict breeding values in wheat crosses with variable ploidy levels.

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