Holstein-Friesian Population Research Articles

Detection of Quantitative Trait Loci Influencing Conformation Traits and Calving Ease in Holstein-Friesian Cattle

An extension of our previous genome scan of a North American Holstein-Friesian population was conducted to identify quantitative trait loci (QTL) affecting conformation traits. Resource families consisted of 1404 sons of 10 elite sires. Genome coverage was estimated to be 2713.5 cM (90%) for 406 markers using a granddaughter design. Regression interval mapping was used to detect QTL affecting 22 conformation traits, including body, udder, feet and legs, and dairy conformation as well as calving ease. Analysis of the families jointly identified 41 chromosome-wise significant QTL influencing conformation traits and 3 significant QTL influencing calving ease on 20 chromosomes. The false discovery rate method was used to account for multiple testing and 3/4 of the suggestive and 5/6 of significant QTL should be real effects. Fourteen of the 44 QTL were significant at the genome-wise level. Comparison of these results with other published reports identifies common QTL affecting conformation traits. Regions on 10 chromosomes appear to affect multiple traits, including conformation, milk production, and somatic cell score, within these particular US Holstein families. Additional work is needed to determine the precise locations of the QTL and select positional candidate genes influencing these traits.

Genetic and Environmental Trends for Milk Traits in the Zimbabwean Holstein-Friesian Population

Genetic and Environmental Trends for Milk Traits in the Zimbabwean Holstein-Friesian Population

Environmental Factors Affecting Milk Production in the Holstein-Friesian Population of Zimbabwe

Environmental Factors Affecting Milk Production in the Holstein-Friesian Population of Zimbabwe

Genetic trends for milk, fat and protein in the Zimbabwean Holstein-Friesian population from 1973 to 1994

Abstract. Genetic trends based on 30 395 records with parities 1 to 8 were estimated using average information restricted maximum likelihood algorithm (AIREML), which had overall mean, herd, month of calving, year of birth, parity and linear and quadratic effects of days in milk. Due to changes in the Zimbabwean milk recording system data set was split into records of cows born from 1973 to 1989 and the other from 1987 to 1994. The first data set was further split into even numbered herds (EVNH73) and odd numbered herds (ODNH73), due to computational limitations. The highest milk production was from May to August. Peak milk production was observed in parity 4. The heritabilities for FCM (0.22 to 0.26), fat percent (0.24 to 0.28) and protein percent (0.21) were comparable to literature values. The annual genetic trends of FCM ranged from 8.36 kg to 13.2 kg, fat per cent ranged from 0.0 % to −0.008 % and protein per cent was −0.003 % in the three data sets. Genetic trends for milk yield, fat and protein yield were also positive but overally lower than in most other countries. The positive genetic trends obtained for milk, fat and protein yields imply that some progress has been made in increasing the milk production despite the relatively small population and significant restrictions. There is need to develop a selection index to improve milk yield and milk composition.

A mammary gland EST showing linkage disequilibrium to a milk production QTL on bovine Chromosome 14.

As part of a genome scan, ESTs derived from mammary gland tissue of a lactating cow were used as candidate genes for quantitative trait loci (QTL), affecting milk production traits. Resource families were genotyped with 247 microsatellite markers and 4 polymorphic ESTs. It was shown by linkage analysis that one of these ESTs, KIEL_E8, mapped to the centromeric region of bovine Chromosome (Chr) 14. Regression analysis revealed the presence of a QTL, with significant effect on milk production, in this chromosome region, and analysis of variance showed no significant interaction of marker genotype and family. The estimated significant differences between homozygous marker genotypes were 140 kg milk, -5.02 kg fat yield, and 2.58 kg protein yield for the first 100 days of lactation. Thus, there was strong evidence for a complete or nearly complete linkage disequilibrium between KIEL_E8 and the QTL. To identify the biological function of KIEL_E8, we extended the sequence for 869 bp by 5'-RACE. A 560-bp fragment of this shows a 90.9% similarity to a gene encoding a cysteine- and histidine-rich cytoplasmic protein in mouse. Although such a protein may have a regulatory function for lactation and a linkage disequilibrium between the EST marker and the QTL has been observed, it remains to be elucidated whether they are identical or not. Nevertheless, KIEL_E8 will be an efficient marker to perform marker-assisted selection in the Holstein-Friesian population.

Review of Holsteinization on Intensive Pastoral Dairy Farming in New Zealand

During the last 20 yr, the percentage of Holstein Friesian (HF) cows in the New Zealand (NZ) herd with North American Holstein genetics has increased from 2 to 38%. The use of North American Holstein genetics was increased to broaden the genetic base of the HF population in NZ and to incorporate traits for high productivity. Analysis of the national database and several comparative studies have shown that, in general, North American-derived Holstein cows were heavier, produced more milk volume and protein yield, had lower concentrations of fat and protein, and had poorer fertility and survival than NZ HF cows. Failure to get in calf and maintain a 365-d calving interval appears to be one of the key reasons for the reduced survival of North American Holstein cows within a seasonal dairying system. Analysis of the productive, reproductive, and survival characteristics of North American Holstein and NZ HF cows revealed an average advantage of $NZ 4950 per farm per year in favor of NZ HF cows, which represented approximately a 12% difference in economic farm surplus. If the population of Holstein genetics outside New Zealand is to be used in NZ pastoral dairying systems, these results suggest that fertility traits should be included in the national breeding objectives.

Effects of cow families on production traits in dairy cattle

AbstractThe components of phenotypic variance attributable to maternal lineage for production traits of the UK Holstein Friesian dairy population were estimated. First lactation production records of 55 230 cows calving between 1996-1998 in the UK Holstein Friesian population were used in the analysis. Maternal pedigree records were traced back to 1960 to establish maternal lineages. The tracing resulted in 36 320 cows being assigned to 11 786 cow families with more than one cow per maternal lineage. Using test day records it was possible to explore aspects of the lactation curve in terms of persistency and different periods of production. The traits analysed were 305-day milk yield and composition traits, the first three milk yield tests of lactation and two measures of persistency. A contemporary record design was used to minimize pair-wise additive direct genetic relationships between cows within a maternal lineage and to remove both the effect of heterogeneous variance over time and the complications of permanent environment effects. No significant component of variance attributable to maternal lineage was found for yield traits. When data were restricted to maternal lineages with five or more records, persistency, as a ratio of cumulative yield in the last third to that in the first third of a 300-day lactation, was estimated to have a 4·4% component due to maternal lineage variance significant at the 5% level. The study also investigated the preferential treatment of cow families. Some evidence of maternal lineage×herd interaction was found.

Effect of Milk Protein Genotypes on Milk Protein Composition and Its Genetic Parameter Estimates

The effects of κ-casein (CN) and β-lactoglobulin (LG) genotypes on milk protein concentration and composition were estimated for the US Holstein-Friesian population using a single-trait, mixed, linear animal model on 592 individual milk samples from 233 cows. Both milk protein genotypes had no statistically significant effect on the total milk protein concentration; however, substitution of the κ-CN A allele additively increased the proportion of κ-CN, and substitution of the β-LG B allele additively increased the proportion of β-LG in total milk protein. In response, proportions of the other milk proteins, mainly αS1-CN, were decreased. For proportions of αS1-CN, κ-CN, and β-LG in total milk protein, κ-CN and β-LG genotypes explain more than 50 and 25% of the heritability and repeatability estimates, respectively. We concluded that κ-CN and β-LG genotypes affect the phenotypic and genetic variation of milk protein composition but do not significantly affect milk protein concentration. A possible explanation for our conclusion is that altered gene sequences in the promoter region of κ-CN B and β-LG A, linked closely to the respective genotypes, favor the transcription or translation of their own protein at the expense of the synthesis of other milk proteins, in particular of αS1-CN.

A genome scan for QTL influencing milk production and health traits in dairy cattle.

A genome scan was conducted in the North American Holstein-Friesian population for quantitative trait loci (QTL) affecting production and health traits using the granddaughter design. Resource families consisted of 1,068 sons of eight elite sires. Genome coverage was estimated to be 2,551 cM (85%) for 174 genotyped markers. Each marker was tested for effects on milk yield, fat yield, protein yield, fat percentage, protein percentage, somatic cell score, and productive herd life using analysis of variance. Joint analysis of all families identified marker effects on 11 chromosomes that exceeded the genomewide, suggestive, or nominal significance threshold for QTL effects. Large marker effects on fat percentage were found on chromosomes 3 and 14, and multimarker regression analysis was used to refine the position of these QTL. Half-sibling families from Israeli Holstein dairy herds were used in a daughter design to confirm the presence of the QTL for fat percentage on chromosome 14. The QTL identified in this study may be useful for marker-assisted selection and for selection of a refined set of candidate genes affecting these traits.

Quantifying genetic contributions to a dairy cattle population using pedigree analysis

A variety of techniques were employed in the analysis of the change in genetic diversity of the UK Holstein–Friesian population over the last 30 years using the Holstein Friesian Society database (which has a base year of 1960). The parameters estimated were average inbreeding coefficient, average degree of relationship between cows, and two measures of genetic diversity, founder equivalent and founder ancestor number. The cow population was seen to change in founder origin from 96% British Friesian in 1967 to 24% British Friesian and 76% North American Holstein in 1997. The change in origin was seen to affect the rate of increase in inbreeding and to a lesser extent relationship, however the measures of genetic diversity were largely unaffected by the Holstein importation. In 1997 average relationship between cows had reached 1.34%, average inbreeding coefficient was 0.4% and the founder equivalent and founder ancestor number had converged at 93. The average inbreeding coefficient was seen to fall from 0.74% in 1982 to 0.38% in 1992 and to remain fairly constant up to 1997. The maternal structure of the cow population born in 1997 was also analysed. It was found that 93% of the cows were in maternal families of only one to four cows and only 0.5% of cows were in maternal families with more than 100 members, where a maternal family is a group of cows related only by maternal lineage.

Identification of sources of heterogeneous residual and genetic variances in milk yield data from the Spanish Holstein-Friesian population and impact on genetic evaluation

Data from the Spanish Holstein-Friesian milk recording system were used to investigate sources of heterogeneity of genetic and residual variation and to evaluate the impact in the genetic evaluation. Factors such as period of time, herd level of production, geographical region, herd size and year of calving were found to be associated with heterogeneity of genetic and residual variation. This stratified the 7664 herd-year of calving into 395 strata defined by combinations of levels of these factors. In order to improve the accuracy of estimates of strata dispersion a mixed model structure in the log–linear model was considered which included the single factors acting additively as fixed effect plus the random third order interaction for residual variance and the single factor acting additively as fixed effect for sire variance. The average value for heritabilities estimated was 0.26, with maximum and minimum values being 0.52 and 0.11, respectively. The 25 and 75 percentiles were 0.20 and 0.32, respectively. Genetic evaluations were compared using three alternative models differed in the dispersion structure: Homogeneous genetic and residual variance, homogeneous genetic and residual variance after data standardization and the heterogeneous variance model with the current genetic and residual variance estimated. Assuming a homogeneous variance model produced an overdispersion with respect to the expected dispersion of both yield deviations and predicted genetic values in large variance environments and the contrary was observed in low variance environments. Precorrection by phenotypic standardization seems to correct for the phenotypic adequately but dispersion of predicted genetic values of animal in environments with large heritability was underestimated with respect to the heterogeneous variance model.

BLAD genotypes and cow production traits in Hungarian Holsteins

BLAD genotypes and cow production traits in Hungarian Holsteins

Use of test day yields for the genetic evaluation of production traits in Holstein-Friesian cattle

Bayesian methods and Gibbs sampling techniques have been applied to estimate genetic parameters for test-day (TD) yields in the Spanish Holstein-Friesian population. Three models were analyzed: (a) multitrait model on successive TD yields within the first lactation; (b) multitrait model on the first three lactations considering TD yields as repeated measures within lactations; (c) random regression model (RRM) on first lactation TD yield. Two alternative RRM were adjusted, RRM1 considered random regression on the genetic effects only, RRM2 included random regressions for the genetic and permanent environmental effects and allowed for heterogeneous residual variances. In model (a), heritabilities tended to be larger in middle lactation and genetic correlations among TD measures were large (>0.80). Large genetic correlations among lactations (>0.89) and heterogeneous variances for first vs. other lactations were found for model (b). RRM1 was found to be superior to the simple repeatability model (b) in terms of reducing residual variance. However, RRM1 produced very large estimates of the genetic variance at the beginning and end of the lactation. Genetic and environmental variances estimated under RRM2 tended to be close to the multitrait model (a). Large discrepancies in the genetic correlations among daily yields with respect to the one observed from the multitrait approach were found for RRM1 and, to a lesser extent, for RRM2.

Method and effects of incorporating foreign information into United Kingdom production evaluations

AbstractCountries, which import a significant amount of semen, embryos and animals, are faced with the problem of how properly to evaluate the animals in the national evaluation system when information on the foreign parents is generally missing. Additional problems arise when the foreign parents obtain an evaluation, usually on the basis of progeny, in the country of import with the result that there are two published evaluations for the animals in question. This paper presents a post-iterative method of incorporating foreign information into home country evaluations. The foreign information is initially converted to the same scale and base as in the home country using procedures recommended by the International Bull Evaluation Service. The method consists essentially of calculating a combined evaluation for animals with home and foreign information as a weighted average of yield deviations, parent averages and progeny contributions from the foreign and home countries. The combined evaluations are used to adjust the evaluations of progeny on the basis of formulae derived from the usual mixed model equations. The same principles were used to combine reliabilities from the respective home and foreign reliabilities. The results from the application of the method to the United Kingdom (UK) Holstein Friesian population are presented. There was re-ranking of both bulls and cows, especially foreign bulls with few UK daughters.

Analysis of polymorphism in the bovine casein genes by use of the polymerase chain reaction

Methods have been devised for detecting polymorphisms in the bovine beta- and kappa-casein genes using the polymerase chain reaction (PCR) followed either by restriction enzyme digestion (to reveal a restriction fragment length polymorphism (RFLP] or by hybridization of an allele-specific oligonucleotide. These methods, as well as being faster and more sensitive than traditional RFLP methods, are of more general applicability since they can detect any change in DNA sequence. They require only a small sample of blood or semen and are applicable to animals of any age or sex. These methods make possible large-scale screening and thus selection for alleles at these loci. Typing of blood DNA can give erroneous results when the animal concerned is a twin; however, this can be overcome by retesting using milk or semen. Analysis of the kappa-casein genotype of Holstein-Friesian bulls gives frequencies for the A and B alleles of 0.80 and 0.20 respectively. Selection in favour of the B allele, which is superior for cheese production, could thus have a large effect. The A3 and B alleles at the beta-casein locus have been shown to be rare in the Holstein-Friesian population. Linkage disequilibrium exists between beta-casein B and kappa-casein B.