Genetics of heifer puberty in two tropical beef genotypes in northern Australia and associations with heifer- and steer-production traits

Johnston, David; Barwick, Stephen; Corbet, N. J.; Fordyce, Geoffry; Holroyd, R. G.; Williams, Patrick James; Burrow, H. M.

doi:10.1071/ea08276

Cited by 119 publications

(97 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In contrast to heritabilities of ,0.10 for most traditional reproductive traits, Johnston et al (2009) report that several pubertal traits such as age, weight and fat depth at time of first CL/CA were moderately to highly heritable (Table 2). In general, more genetic variation was observed for Brahmans than for Tropical Composites.…”

Section: Component Traits Of Female Reproductionmentioning

confidence: 91%

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Burrow

2012

Animal

View full text Add to dashboard Cite

This paper examines the relative importance of productive and adaptive traits in beef breeding systems based on Bos taurus and tropically adapted breeds across temperate and (sub)tropical environments. In the (sub)tropics, differences that exist between breeds in temperate environments are masked by the effects of environmental stressors. Hence in tropical environments, breeds are best categorised into breed types to compare their performance across environments. Because of the presence of environmental stressors, there are more sources of genetic variation in tropical breeding programmes. It is therefore necessary to examine the genetic basis of productive and adaptive traits for breeding programmes in those environments. This paper reviews the heritabilities and genetic relationships between economically important productive and adaptive traits relevant to (sub)tropical breeding programmes. It is concluded that it is possible to simultaneously genetically improve productive and adaptive traits in tropically adapted breeds of beef cattle grazed in tropical environments without serious detrimental consequences for either adaptation or production. However, breed-specific parameters are required for genetic evaluations. The paper also reviews the magnitude of genotype 3 environment (G 3 E) interactions impacting on production and adaptation of cattle, where 'genotype' is defined as breed (within a crossbreeding system), sire within breed (in a within-breed selection programme) or associations between economically important traits and single nucleotide polymorphisms (SNPs -within a marker-assisted selection programme). It is concluded that re-ranking of breeds across environments is best managed by the use of the breed type(s) best suited to the particular production environment. Re-ranking of sires across environments is apparent in poorly adapted breed types across extreme tropical and temperate environments or where breeding animals are selected in a temperate environment for use in the (sub)tropics. However, G 3 E interactions are unlikely to be of major importance in tropically adapted beef cattle grazed in either temperate or (sub)tropical environments, although sex 3 environment interactions may provide new opportunities for differentially selecting to simultaneously improve steer performance in benign environments and female performance in harsher environments. Early evidence suggests that re-ranking of SNPs occurs across temperate and tropical environments, although their magnitude is still to be confirmed in well-designed experiments. The major limitation to genetic improvement of beef cattle over the next decade is likely to be a deficiency of large numbers of accurately recorded phenotypes for most productive and adaptive traits and, in particular, for difficult-to-measure adaptive traits such as resistance to disease and environmental stressors.

show abstract

Section: Component Traits Of Female Reproductionmentioning

confidence: 91%

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Burrow

2012

Animal

View full text Add to dashboard Cite

show abstract

“…In beef, Johnston et al (2009) reported indirect evidence of a negative genetic correlation (−0.6) between fertility (age at puberty) in heifers and RFI measured in their paternal half-brothers for Brahman, but not for Brahman crosses (where the genetic correlation is 0.02). Vallimont et al (2012) used a data set of 970 Holsteins and found unfavourable genetic correlations between RFI and three measures of fertility (daughter pregnancy rate, cow conception rate and heifer conception rate).…”

Section: Impact Of Selecting For Rfi On Other Traitsmentioning

confidence: 99%

Genomic selection for feed efficiency in dairy cattle

Pryce

Wales

Haas

et al. 2014

Animal

View full text Add to dashboard Cite

Feed is a major component of variable costs associated with dairy systems and is therefore an important consideration for breeding objectives. As a result, measures of feed efficiency are becoming popular traits for genetic analyses. Already, several countries account for feed efficiency in their breeding objectives by approximating the amount of energy required for milk production, maintenance, etc. However, variation in actual feed intake is currently not captured in dairy selection objectives, although this could be possible by evaluating traits such as residual feed intake (RFI), defined as the difference between actual and predicted feed (or energy) intake. As feed intake is expensive to accurately measure on large numbers of cows, phenotypes derived from it are obvious candidates for genomic selection provided that: (1) the trait is heritable; (2) the reliability of genomic predictions are acceptable to those using the breeding values; and (3) if breeding values are estimated for heifers, rather than cows then the heifer and cow traits need to be correlated. The accuracy of genomic prediction of dry matter intake (DMI) and RFI has been estimated to be around 0.4 in beef and dairy cattle studies. There are opportunities to increase the accuracy of prediction, for example, pooling data from three research herds (in Australia and Europe) has been shown to increase the accuracy of genomic prediction of DMI from 0.33 within country to 0.35 using a three-country reference population. Before including RFI as a selection objective, genetic correlations with other traits need to be estimated. Weak unfavourable genetic correlations between RFI and fertility have been published. This could be because RFI is mathematically similar to the calculation of energy balance and failure to account for mobilisation of body reserves correctly may result in selection for a trait that is similar to selecting for reduced (or negative) energy balance. So, if RFI is to become a selection objective, then including it in an overall multi-trait selection index where the breeding objective is net profit is sensible, as this would allow genetic correlations with other traits to be properly accounted for. If genetic parameters are accurately estimated then RFI is a logical breeding objective. If there is uncertainty in these, then DMI may be preferable.

show abstract

“…Cattle were bred and supplied by the Cooperative Research Centre for Beef Genetic Technologies (Beef CRC) as described previously Johnston et al 2009). In brief, data from 1007 Brahman heifers and 1118 Brahman bulls were included in the current analysis.…”

Section: Cattle and Traitsmentioning

confidence: 99%

“…Puberty in heifers was defined by plasma progesterone concentration, ultrasound images of corpus luteum (CL) and detection of oestrous (Shamay et al 2005;Romano et al 2007;Johnston et al 2009). Puberty in bulls was defined by scrotal circumference thresholds and was related to sperm concentration, motility and morphology (Lunstra et al 1978;Bagu et al 2004;Siddiqui et al 2008;Corbet et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Finding genes for economically important traits: Brahman cattle puberty

Fortes

Lehnert

Bolormaa³

et al. 2012

Anim. Prod. Sci.

Self Cite

View full text Add to dashboard Cite

Abstract. Age at puberty is an important component of reproductive performance in beef cattle production systems. Brahman cattle are typically late-pubertal relative to Bos taurus cattle and so it is of economic relevance to select for early age at puberty. To assist selection and elucidate the genes underlying puberty, we performed a genome-wide association study (GWAS) using the BovineSNP50 chip (~54 000 polymorphisms) in Brahman bulls (n = 1105) and heifers (n = 843) and where the heifers were previously analysed in a different study. In a new attempt to generate unbiased estimates of singlenucleotide polymorphism (SNP) effects and proportion of variance explained by each SNP, the available data were halved on the basis of year and month of birth into a calibration and validation set. The traits that defined age at puberty were, in heifers, the age at which the first corpus luteum was detected (AGECL, h 2 = 0.56 AE 0.11) and in bulls, the age at a scrotal circumference of 26 cm (AGE26, h 2 = 0.78 AE 0.10). At puberty, heifers were on average older (751 AE 142 days) than bulls (555 AE 101 days), but AGECL and AGE26 were genetically correlated (r = 0.20 AE 0.10). There were 134 SNPs associated with AGECL and 146 SNPs associated with AGE26 (P < 0.0001). From these SNPs, 32 (~22%) were associated (P < 0.0001) with both traits. These top 32 SNPs were all located on Chromosome BTA 14, between 21.95 Mb and 28.4 Mb. These results suggest that the genes located in that region of BTA 14 play a role in pubertal development in Brahman cattle. There are many annotated genes underlying this region of BTA 14 and these are the subject of current research. Further, we identified a region on Chromosome X where markers were associated (P < 1.00E-8) with AGE26, but not with AGECL. Information about specific genes and markers add value to our understanding of puberty and potentially contribute to genomic selection. Therefore, identifying these genes contributing to genetic variation in AGECL and AGE26 can assist with the selection for early onset of puberty.

show abstract

Genetics of heifer puberty in two tropical beef genotypes in northern Australia and associations with heifer- and steer-production traits

Cited by 119 publications

References 43 publications

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems

Genomic selection for feed efficiency in dairy cattle

Finding genes for economically important traits: Brahman cattle puberty

Contact Info

Product

Resources

About