Bovine Reproduction. Группа авторов

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Bovine Reproduction - Группа авторов


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rel="nofollow" href="#ulink_59738fa0-1b62-5c98-8292-3084757f5195">Figure 6.7), emphasizing the effects of genetics on testicular growth [9–11].

Schematic illustration of regression lines for paired testes weight (PTW) according to scrotal circumference (SC).

      Source: L. Brito, unpublished results.

Schematic illustration of top: regression curves for scrotal circumference (SC) according to age in Holstein, Jersey, Nelore, and Guzera bulls.

      Source: ASB Global Inc., unpublished results.

      Jersey measurements (n = 1038) obtained from bulls 7 to 75 months old; SC = −0.6814 + [40.26 × (log AGE)] – [10.27 × (log AGE)2] (ABS Global Inc., unpublished results). Nelore measurements obtained from bulls (n = 532) 7 to 43 months old; SC = 36.9/1 + [4.22–(0.11 × age)] [118]. Guzera measurements (n = 7410) obtained from bulls 2 to 69 months old; SC = 35.96/1 + [2.86–(0.002 × age in days)] [119]. Bottom: testicular length and width associations with SC between 3 and 16 months of age in Angus and Angus × Charolais bulls (n = 111) receiving adequate nutrition.

      Source: L. Brito, unpublished results.

Schematic illustration of scrotal circumference (± 90% confidence interval) in beef bulls of various breeds (n = approximately 300 000) according to age (top) and weight (bottom).

      Source: From [8], © 2014, Elsevier.

Breed Growth trait r g References
Angus Yearling weight 0.24−0.68 [13, 15]
Sperm concentration 0.54 [16]
Sperm motility 0.36
Total sperm defects −0.23
Composite Yearling weight 0.40−0.43 [36]
Hereford Weaning weight 0.08−0.86 [15, 18]
Yearling weight 0.30−0.52 [19–21]
Weaning–yearling ADG 0.22−0.35 [22, 24]
Sperm concentration 0.77
Sperm motility 0.34
Normal sperm 0.33
Hereford/Simmental Sperm concentration 0.2 [14]
Sperm motility 0.11
Total sperm number 0.19
Limousin Weaning weight 0.14 [26]
Nelore Weaning weight 0.36 [27, 28]
Yearling weight 0.34
Longissimus muscle area 0.28
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