Reproductive Traits and Their Heritabilities in Beef Cattle

Cammack, K. M.; Thomas, M. G.; Enns, R. M.

doi:10.15232/s1080-7446(15)30753-1

Cited by 116 publications

(107 citation statements)

References 105 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Fontoura, Montanholi, Diel de Amorim, Foster, Chenier and Miller successful, as these fertility traits are heritable (Cammack et al, 2009). We found no difference between scrotum surface temperatures among right or left sides between RFI groups, but there was a larger temperature standard deviation at the base of the scrotum in less-feed-efficient bulls.…”

Section: Discussionmentioning

confidence: 49%

Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls

Fontoura

Montanholi

Amorim

et al. 2016

Animal

View full text Add to dashboard Cite

The beef industry has emphasized the improvement of feed utilization, as measured by modeling feed intake through performance traits to calculate residual feed intake (RFI). Evidence supports an inverse relationship between feed efficiency and reproductive function. The objective of this study was to determine the relationship of reproductive assessments and RFI unadjusted (RFI Koch ) or adjusted for body composition (RFI us ) and the relationship among fertility-related parameters. In total, 34 crossbred bulls were housed together for 112 days of performance evaluation, followed by assessment of scrotum IR imaging, scrotal circumference, testes ultrasonography and semen quality parameters at 377 ± 33.4 days of age. Bulls were slaughtered at 389 ± 34.0 days of age, and analyses of carcass composition, biometrics and histomorphometry of the testis and epididymis were conducted. Bulls were grouped into two subpopulations based on divergence of RFI, and within each RFI model either by including 50% of the population (Halves, high and low RFI, n = 17) or 20.6% extremes of the population (Tails, high and low RFI, n = 7). The means of productive performance and fertility-related measures were compared through these categories. Pearson's correlation was calculated among fertility-related measures. In the Halves subpopulation of the RFI us , sperm of low-RFI bulls had decreased progressive motility (47.30% v. 59.90%) and higher abundance of tail abnormalities (4.30% v. 1.80%) than that of high-RFI bulls. In the Tails subpopulation of the RFI Koch , low RFI displayed less variation in the scrotum surface temperature (0.62°C v. 1.16°C), decreased testis echogenicity (175.50 v 198.00 pixels) and larger (60.90 v. 56.80 mm 2 ) but less-developed seminiferous tubules than high-RFI bulls. The evaluation of fertility-related parameters indicated that a higher percentage of immature seminiferous tubules was correlated with occurrence of sperm with distal droplets (r = 0.59), a larger temperature variation at the top of the scrotum was correlated with improved sperm progressive motility (r = 0.38), a lower occurrence of sperm loose head abnormalities was correlated with larger temperature variation at the lower part of the scrotum (r = − 0.43), and a lower minimum testis echogenicity (r = −0.59) and smaller scrotal circumference (r = 0.72) were correlated with age. The adjustment for body composition (RFI determination) enabled distinct biological inferences about reproduction and feed efficiency when compared with the non-adjusted model. However, both RFI models and the correlation analysis supported the hypothesis that feed-efficient bulls have features of delayed sexual maturity. Overall, the assessment of fertility-related measurements is important to avoid the improvement of feed efficiency at the expense of reproductive function in young bulls.

show abstract

Section: Discussionmentioning

confidence: 49%

Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls

Fontoura

Montanholi

Amorim

et al. 2016

Animal

View full text Add to dashboard Cite

show abstract

“…Most significant SNPs in terms of P-values are reported in bold. Note that SNP BTA-97369-no-rs was the only SNP not associated with both calibration and validation dataset for neither AGE26 nor AGECL (see Supplementary Material Tables S1, S2 environmental factors, as well as the use of different phenotypic measurements (Martin et al 1992;Cammack et al 2009). …”

Section: Discussionmentioning

confidence: 99%

“…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). Pubertal traits vary in heritability (h 2 ) from low to moderately high (Cammack 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.

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

“…Hence, improving fertility is the prime aim of most beef producers globally. Longevity, calving interval (CI) and age at first calving (AFC) are among the most important indicators of fertility in cows (Cammack et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Relationship between linear type and fertility traits in Nguni cows

Zindove

Chimonyo

Nephawe

2015

Animal

View full text Add to dashboard Cite

The objective of the study was to assess the dimensionality of seven linear traits (body condition score, body stature, body length, heart girth, navel height, body depth and flank circumference) in Nguni cows using factor analysis and indicate the relationship between the extracted latent variables and calving interval (CI) and age at first calving (AFC). The traits were measured between December 2012 and November 2013 on 1559 Nguni cows kept under thornveld, succulent karoo, grassland and bushveld vegetation types. Low partial correlations (−0.04 to 0.51), high Kaiser statistic for measure of sampling adequacy scores and significance of the Bartlett sphericity test (P < 0.01) showed that there were significant phenotypic correlations between the linear traits and the data were suitable for factor analysis. Two factors had eigenvalues >1. Factor 1 included body condition score, body depth, flank circumference and heart girth and represented body capacity of cows. Factor 2 included body length, body stature and navel height and represented frame size of cows. CI and AFC decreased linearly with increase of factor 1. There was a quadratic increase in AFC as factor 2 increased (P < 0.05). It was concluded that the linear type traits under study can be grouped into two distinct factors, one linked to body capacity and the other to the frame size of the cows. Small-framed cows with large body capacities have shorter CI and AFC.

show abstract

Reproductive Traits and Their Heritabilities in Beef Cattle

Cited by 116 publications

References 105 publications

Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls

Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls

Finding genes for economically important traits: Brahman cattle puberty

Relationship between linear type and fertility traits in Nguni cows

Contact Info

Product

Resources

About