Genetic parameters of testicular measurements in Merino rams and the influence of scrotal circumference on total flock fertility

Duguma, G.; Cloete, S.W.P.; Schoeman, S.J.; Jordaan, G.F.

doi:10.4314/sajas.v32i2.3748

Cited by 20 publications

(22 citation statements)

References 18 publications

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“…The correlation between weight at puberty, SC and BCS could be explained by growth of the ram lambs. This is in agreement with previous research (Duguma et al, 2002;Fourie et al, 2002).…”

Section: Puberty In Ram Lambssupporting

confidence: 94%

Age at Puberty and Some Biological Parameters of Awassi and its First Crosses with Charollais and Romanov Rams

Kridli

Abdullah

Shaker

et al. 2006

Italian Journal of Animal Science

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The aim of this experiment was to determine the age at puberty of both ram and ewe lambs of three genotypes: Awassi (A), Charollais x Awassi (CA), and Romanov x Awassi (RA) F 1 crosses. Twenty, six-month old lambs (10 from each sex) from each genotype were used. Ram and ewe lambs were kept in separate groups from the beginning until the end of the experiment. Birth weight and weaning weight were recorded for all animals. Body weights and body condition scores were recorded at monthly intervals between 6.5 and 12 months of age. Blood samples were collected weekly from ewe lambs and fortnightly from ram lambs to monitor progesterone and testosterone profiles, respectively. Semen characteristics and scrotal circumferences (SC) were evaluated fortnightly. Weight at puberty in ewe and ram lambs were not significantly different among the three genotypes and ranged around 35 kg and 42 kg, respectively. In ewe lambs, age at puberty was significantly higher (P< 0.01) in A (280±11.5 d) than in RA (232±11 d) and CA (255±11.5 d). Age at puberty of ram lambs was also significantly different (P < 0.01) among the three genotypes being higher in A (243±5 d) than in CA (223±5 d) and RA (226±5 d) ram lambs. Semen parameters improved with age in all genotypes. The RA ram lambs had greater semen concentration and lower abnormal spermatozoa than the other two genotypes (P< 0.05). Results of the present study indicate that crossing Awassi ewes with either Charollais or Romanov sires tends to improve reproductive characteristics of the F 1 crossbreds through advancing age at puberty in both ram and ewe lambs. (255 ± 11,5 d). Anche nei maschi l'età alla pubertà è risultata significativamente diversa (P < 0,01) tra i

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“…The correlation between weight at puberty, SC and BCS could be explained by growth of the ram lambs. This is in agreement with previous research (Duguma et al, 2002;Fourie et al, 2002).…”

Section: Puberty In Ram Lambssupporting

confidence: 94%

Age at Puberty and Some Biological Parameters of Awassi and its First Crosses with Charollais and Romanov Rams

Kridli

Abdullah

Shaker

et al. 2006

Italian Journal of Animal Science

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“…The positive association between SC and BW is an indication that improvement in both traits is possible through selection procedures, considering their high genetic correlations (Duguma et al, 2002;Pourlis, 2011). This is an indication that genes that contributed to BW had an influence in the reproductive ability of rams.…”

Section: Discussionmentioning

confidence: 94%

Evaluation of Three Mathematical Functions to Describe the Relationship Between Body Weight, Body Condition and Testicular Dimensions in Yankasa Sheep

Yakubu

Musa-Azara

2013

Int. J. Morphol.

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SUMMARY:Body size and testicular measurements have been found to be important parameters utilized in breeding soundness evaluation. The present study therefore, aimed at determining the relationship between body weight (BW), body condition score (BCS), testicular length (TL), testicular diameter (TD) and scrotal circumference (SC) in 120 extensively reared Yankasa rams (approximately 30 months old) using linear, quadratic and cubic predictive models. Coefficient of determination (R 2 ), Adjusted R 2 , the estimate of Mallows' Cp, RMSE (Root mean squares error) and the parsimony principle (p=number of parameters) were used to compare the efficiency of the different models. Strong Pearson's correlation coefficients (r = 0.83-0.94; P<0.01) were found between BW, TL, TD and SC. Spearman correlations between BCS and other variables were also highly significant (r = 0.78-0.85; P<0.01). SC was the sole variable of utmost importance in estimating BW, which was best predicted using the cubic model. However, the optimal model for BW prediction comprised TD, SC and BCS with p, R The present findings could be exploited in husbandry and selection of breeding stock for sustainable sheep production especially within the resource-poor farming system under tropical and subtropical conditions.

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“…In sheep breeding, it is well known that type traits have an important influence on sheep performance. Measures of size and body form are desired in many experiments with sheep, including studies of growth, inheritance and nutrition (Duguma et al, 2002;Fourie et al, 2002;Janssens and Vandepitte, 2004;Kunene et al, 2007;Mandal et al, 2008). In meat-producing species, body conformation and growth rate of animals are important selection criteria (Mandal et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Estimation of Genetic Parameters for Body Measurements and Their Relationship With Body Weight in Barki Lambs

Gad

2014

Journal of Animal and Poultry Production

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The aim of the present study was to investigate the importance of direct and maternal effects on the body measurements and live weight of Barki lambs. Data of 214 lambs progenies from 36 sires and 98 dams recorded of Barki of Sheep flock in Maryout Research Station at Desert Research Center was used to estimate the genetic parameters of body measurements and yearling live weight in Barki lambs. The used traits in present study were: body length (BL), height at withers (HW), heart girth (HG) and yearling weight (YW). The estimations were done by using DFREML software. Direct heritability by single trait analysis was estimated 0.10, for BL, 0.18, for HW, 0.10, for HG, and 0.10, for YW. The effect of permanent environmental due to dam was estimated 0.05, 0.02, 0.06 and 0.04 for BL, HW, HG and YW, respectively. Using bivariate analysis, additive genetic correlations were estimated 0.75, 0.76 and 0.93 between YW and each of BL, HW and HG, respectively. High and positive genetic and phenotypic correlations indicate that an improvement in body measurements both at the genetic and phenotypic level is expected through selection on body weight and vice versa. keywords: Barki lambs,direct heritability, permanent environmental and genetic correlation.

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Genetic parameters of testicular measurements in Merino rams and the influence of scrotal circumference on total flock fertility

Cited by 20 publications

References 18 publications

Age at Puberty and Some Biological Parameters of Awassi and its First Crosses with Charollais and Romanov Rams

Age at Puberty and Some Biological Parameters of Awassi and its First Crosses with Charollais and Romanov Rams

Evaluation of Three Mathematical Functions to Describe the Relationship Between Body Weight, Body Condition and Testicular Dimensions in Yankasa Sheep

Estimation of Genetic Parameters for Body Measurements and Their Relationship With Body Weight in Barki Lambs

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