Estimates of Heterosis for Sexual Activity in Boars

Abstract

Data on 118 Duroc, Yorkshire and reciprocal cross boars were utilized to evaluate the effect of crossbreeding on mating behavior. Boars were penned with an estrous gilt on 2 consecutive days. Number of mounts (proper and improper), sexual interest score and whether a successful mating occurred were recorded. Times at which each of these events occurred were recorded also, allowing calculation of times to first mount, to final mount and to completion of mating. Most importantly, more crossbred boars completed a mating than purebred boars (69 vs 27%). Crossbreds had greater sexual interest (P less than .05), more mounts and a higher proportion of properly oriented mounts (P less than .05). Crossbreds also began mounting activity (first mount, first proper mount and final mount; P less than .05) earlier and required less time to complete a mating (P less than .05) than purebred boars. Heterosis values for number of proper and improper mounts, proportion of proper mounts and sexual interest were 2, 53, 32 and 52%, respectively. Time to first mount, to final mount and to completing mating had heterosis values of -34, -29 and -20%, respectively. Scrotal measures taken at 140 and 168 d and at post-trial castration, as well as excised testes measures and sperm numbers, showed heterosis; however, no consistent associations between these traits and behavior traits were found. These data suggest that crossbred boars were more sexually active than purebred boars, perhaps due to an advanced physiological or behavioral stage.

The relationships between the performance test results of young crossbred boars

“…breeding performance and the possibility of their longer use as compared to the pure breed animals. It is confirmed by the results of many authors' studies (Czarnecki, et al, 1999;Fent, et al, 1980;Kapelański, 1995;Knap, 1987;Michalska, 1996;Michalska, et al, 2004Michalska, et al, , 2010Milewska, 2007;Milewska and Falkowski, 2001;Neely and Robison, 1983;Neely, et al, 1980;Nowachowicz, et al, 2009;RóŜycki, 1995). In a Polish pig breeding and keeping the boars of breeds: Hampshire, Duroc, Pietrain and two-breed crossbreds came from the reciprocal crossing determine the paternal component and are performance tested.…”

Quality of semen of young boars of the breeds Pietrain and Duroc and their reciprocal crosses

“…Therefore many countries, including Poland, have been using not only hybrid sows but also hybrid boars for reproduction for many years. Many studies have proved that they are characterized by a better libido, larger testis size, better quality of semen and a higher conception rate percentage than in purebred boars (WILSON et al, 1977;NELLY et al, 1980;FENT et al, 1983;NELLY and ROBISON, 1983). The current recommended crossing of pig breeds has two stages, and uses four breedstwo mother breeds and two father breeds.…”

The effect of season on semen parameters in cross-bred boars and phenotypic correlations between semen characteristics in different seasons

“…In recent years cross-bred boars have enjoyed considerable popularity. According to many authors these boars produce quantitatively and qualitatively better ejaculates than pure-bred boars (Kondracki et al, 2003;Neely and Robison, 1983;Wysokińska and Kondracki, 2004). This should not, however, be accepted as a rule, as the effects of cross-breeding depend to a considerable degree on the selection of breeds and on the cross-breeding programme.…”