Genetic Parameters for Testes Size and Sperm Number in Hereford Bulls

Neely, J. D.; Johnson, Blake; Dillard, E. U.; Robison, O. W.

doi:10.2527/jas1982.5551033x

Cited by 47 publications

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“…This correlaCorrelation coefficient (r) 0.21 0.10 -0.14 Table 3. Correlation coefficients Propertics between thc testosterone values of blood (n = 40) __ at the beginning and at Testosterone content of blood plasma before the GnRB treatment (nmolil) the end Of the self-performance Testosterone content of blood plasma after the GnRH treatmcnt (nmolil) Changc of testosterone content of the blood plasma (nmolil) tion is not as close as some previous (r = 0.92) results (Aehnelt et al 1972), however, it is nearly the same as some other (r = 0.49) findings (Neely and Johnson 1988). From the authors previous experiment with Charolais breeding bulls, correlation values of r = 0.6-0.7 were found in two different stock farms (J. T6zsCr et al unpubl.…”

Section: Resultssupporting

confidence: 80%

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

Mézes

Tőzsér

Nagy

et al. 1997

Reprod Domestic Animals

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ContentsThe authors invcstigated the effect of age on GnRH induced testosterone response and its correlation with body weight and some morphometric traits such as scrotal circumference, width of chest, height of shoulder, depth of chest in Charolais breeding bull candidates at the beginning and the end of the self-performance test in an age matched group ( & 30 days).It was found that the correlation in the case of age and testosterone content of blood serum before and after GnRH treatment was low. The multiple correlation with morphomctric traits i s moderate which supports the well-known effect of testosterone on muscle formation.Moderate or close correlation was found in respect of GnRH test results and scrotal circumference and those correlation remained the same at the beginning and the end of the selfperformance test, which suggests the possibility of early selection of breeding bull candidates.The relatively high individual variance among the bulls in the case of GnRH test results and some morphometric traits suggest some endocrinological differences among the different types of bulls within the same genotype and it would be a possible marker for type-selection. Inhalt Einige andrologische Parameter bei Charolais-Zuchtbullen im EigenleistungstestEs wurde ein Alterseffekt auf die durch GnRH induzierte Testosteron-Antwort und die Korrclation zu Korpergewicht und einigen morphometrischen Parametcrn, wie Umfang des Hodensacks, Brustumfdng, Schulterhohe, Tiefe der Brust bci Charolais-Bullen zu Beginn und am Ende eines Eigenleistungstests in altersabhingigen Gruppen (+30 Tage) untersucht.Dabci wurde herausgefunden, dab die Korrelation zwischen Alter und Bluttestosterongehalt vor und nach GnRH-Behandlung nur schwach ausgespragt ist. Die multiple Korrelation zwischen morphometrischen Werten war eher maBig und bestatigt damit die gut bekannten Effekte von Testosteron auf die Muskelausbildung. Hinsichtlich der AbhBngigkeit von GnRH und Hodensackumfang wurden mittelmiiDige his hohe Korrelationen gefunden und waren zu Beginn und am Ende der Eigenleistungspriifung gleich. Hieraus la& sich die Moglichkeit ableiten, bei zuchtbullen eine friihe Sclektion vorzunehmen.Die relativ hohe individuelle Varianz zwischen Bullcn bei den GnRH-Ergebnissen und bei einigen morphologischen Ergebnissen lassen auf unterschiedliche endokrinologische Muster zwischen verschiedenen Rullentypen innerhalh des selben Genotyps schliel3en. Dieses kiinnte als moglicher Marker fur eine Typenselcktion verwendet wcrden.

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Section: Resultssupporting

confidence: 80%

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

Mézes

Tőzsér

Nagy

et al. 1997

Reprod Domestic Animals

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“…These values are somewhat less than the lower plateaus of number of sperm in the semen ( Figure 5). High correlations of testicular size with sperm output have been found in swine (Wilson et al, 1977;Egbunike and Elemo, 1978;Neely et al, 1980;Fent et al, 1983), sheep (Knight 1977(Knight , 1984, and cattle (Hahn et al, 1969;Almquist et al, 1976;Coulter et al, 1976;Neely et al, 1982). None of the studies compared lines that differed in testis size due to selection.…”

Section: Discussionmentioning

confidence: 97%

Effect of selection for size of testes in boars on semen and testis traits.

Huang

Johnson

1996

Journal of Animal Science

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ABSTRACT:The objective of this study was to evaluate the effects of selection for increased size of testes on semen and testis characteristics. Boars from a line selected for increased size of testes at 150 d of age (TS, n = 25) and a randomly selected control line (C, n = 18) were used. Semen was collected three times per week for 3 wk (TRT1) then daily for 3 wk (TRT2) beginning when boar age averaged 276 d. It was followed by a 4-wk period of one collection per week and then the TRT1-TRT2 sequence was repeated. After 64 collections, boars were castrated and testes were evaluated for sperm numbers. Volume of semen, percentage of motile sperm cells, and percentage of abnormal cells in the semen did not differ ( P > .05) between lines. Concentration of sperm cells in the semen was greater for TS boars at TRT 1 (35.0 million cells/mL, P < .10) and TRT 2 (29.5 million cells/mL, P < .01). Number of sperm cells per ejaculate was greater for TS boars (6.1 and 4.3 billion cells for TRT 1 and TRT 2, respectively; P < .05). Percentage of abnormal cells was less ( P < .05) for boars at the younger ages. Concentration of sperm cells was 16 to 18 million cells/mL semen greater ( P < .05) at the older ages. Significant differences in the shapes of the response curves with increasing collection number across lines and ages were found. These differences were small and not considered to be important. Line differences in testicular and epididymal sperm numbers and in daily sperm production were consistent with differences in semen traits. Repeatabilities of semen traits were between .16 and .74. Selection for increased size of testes can be used to improve the reproductive capacity of boars used for artificial insemination.

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“…Scrotal circumference is easy and inexpensive to measure, has moderate heritability, and is reported to be favorably associated with female fertility (Brinks et al, 1978;Morris et al, 1992;Vargas et al, 1998). Positive genetic correlations between SC and growth traits (Bourdon and Brinks, 1986;Smith et al, 1989;Keeton et al, 1996) and between SC and semen quality traits (Neely et al, 1982;Knights et al, 1984;Smith et al, 1989) have been reported.…”

Section: Introductionmentioning

confidence: 99%

Genetic relationships between scrotal circumference and female reproductive traits1

Martínez-Velázquez

Gregory

Bennett

et al. 2003

Journal of Animal Science

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ABSTRACT:Records for yearling scrotal circumference (SC; n = 7,580), age at puberty in heifers (AP; n = 5,292), age at first calving (AFC; n = 4,835), and pregnancy, calving, or weaning status following the first breeding season (PR1, CR1, or WR1, respectively; n = 7,003) from 12 Bos taurus breeds collected at the Meat Animal Research Center (USDA) between 1978 and 1991 were used to estimate genetic parameters. Age at puberty (AP) was defined as age in days at first detected ovulatory estrus. Pregnancy (calving or weaning) status was scored as one for females conceiving (calving or weaning) given exposure during the breeding season and as zero otherwise. The final model for SC included fixed effects of age of dam at breeding (AD), year of breeding (Y), and breed (B) and age in days at measurement as a covariate. Fixed effects in models for AP and AFC were AD, Y, B, and month of birth. Fixed effects in models for PR1, CR1, and WR1 included AD, Y, and B. For all traits, random effects in the model were direct genetic, maternal genetic, maternal permanent environmental, and residual. Analyses for a three-trait animal model were carried out with SC, AP, and a third

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Genetic Parameters for Testes Size and Sperm Number in Hereford Bulls

Cited by 47 publications

References 0 publications

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

Some Andrological Parameters of Charolais Breeding Bulls in Self‐performance Test

Effect of selection for size of testes in boars on semen and testis traits.

Genetic relationships between scrotal circumference and female reproductive traits1

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