Reproductive and Testicular Characteristics of Purebred and Crossbred Boars2

Abstract

SUMMARYOne-hundred-ninety-five Duroc (D), Hampshire (H), Duroc X Hampshire (DXH) and Hampshire X Duroc (HX D) boars were evaluated for reproductive performance. One-hundred-sixteen boars were castrated at approximately 225 days of age to evaluate testicular and epididymidal weights and sperm numbers. Testes from crossbred boars were 95.33 + 22.81 g heavier (P<.01) and contained 14.4I + 3.92 billion more sperm (P<.01) than those from purebred boars. Testes from Hampshire boars were 50.40 + 31.75 g heavier with 6.27 + 5.45 billion more sperm than those from Durocs. There were no significant differences between breeds for caput-corpus epididymidal measurements. Durocs had 24.55 + 12.16 billion more sperm (P<.05) in the cauda epididymis than Hampshire boars. Testes weight and testes sperm numbers were significantly correlated with caput-corpus epididymidal and cauda epididymidal sperm numbers. Correlations of testicular and epididymidal characteristics with growth rate and backfat to 100 kg were small and nonsignificant.Twenty 7.5-month to 9-month-old D, Dx H and HXD boars and 19 H boars were each mated to two Yorkshire gilts to evaluate reproductive efficiency. Conception rates were: D, 63.2%; DXH, 67.5%; HXD, 60.0%; and H, 48.6%. Number of embryos 30-days postbreeding was 10.66 + .49 and 11.25 -+ .43 (P>.10) for gilts mated to purebred and crossbred sires, respectively. Twenty-eight of 36

Reproductive Performance for Four Breeds of Swine: Crossbred Females and Purebred and Crossbred Boars

“…The advantage in conception rate when crossbred boars were used in natural service agreed with other reports (Wilson et al, 1977; Anderson et al, 1981). Conlon and Kennedy (1978) used semen from purebred and crossbred boars to artificially breed gilts and showed a very small crossbred boar advantage in conception rate.…”

“…If so, the reduced advantage for the entire breeding season is not surprising because the purebred boars would have matured during the 8 wk of breeding. More advanced sexual maturity (measured by testis weight and sperm numbers) in crossbred boars has been demonstrated by several studies (Hauser et al, 1952;Wilson et al, 1977;Fent, 1980;Neely et al, 1980 aThere were 15 to 18 boars in each breed group. bNumber of litters.…”

“…The advantage of a crossbred female is clear, but there has been less research concerning the use of crossbred boars. Studies on young crossbred boars have generally shown an advantage in testis weight, mating behavior and conception rate (Hauser et al, 1952;Lishman et al, 1975;Wilson et al, 1977;Conlon and Kennedy, 1978;Neely et al, 1980), but more information is needed. There is also less information on the performance of the Landrace and Spotted breeds than for Durocs, Yorkshires or Hampshires.…”

Genetic evaluation for semen characteristics in a crossbreeding project involving Saudi and Spanish V-line rabbits

“…In other species, such as pigs, it seems that crossbred males could be more advanced in sexual maturity. However, at the adult stage, differences among purebred and crossbred bucks in semen parameters tend to disappear (Wilson et al, 1977;Buchanan and Johnson, 1984). In general, crossbreeding among breeds raised in hot climates was associated with heterotic effects in semen characteristics as stated by El-Ezz et al (1985) in Egypt and Al-Sobayil and Khalil (2002) in Saudi Arabia.…”

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

“…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.…”