A total of 12 717 ejaculates from 74 Yorkshire, 25 Hampshire, 35 Duroc, 27 Landrace and 5 Lacombe boars were measured for semen volume, sperm concentration, percentage live sperm, motility and potential doses of semen. The data were collected by the Ontario Swine AI Association between 1971 and 1980. Boar repeatability and the effects of breed of boar, technician, year, month, day of the week, interval between collections and age of boar were examined. Boar repeatabilities were 0.21 for volume, 0.32 for concentration, 0.28 for percentage live sperm, 0.21 for motility score and 0.30 for potential doses. Breed of boar effects were significant for all semen measures. Potential doses were highest for Yorkshire (14.7), followed by Landrace (13.7), Duroc (12.9), Hampshire (12.5) and Lacombe (7.7). Differences between technicians were significant for all measures except potential doses. Technicians who collected greater semen volume obtained ejaculates with lower sperm concentration, which resulted in no real di...

Boar, breed and environmental factors influencing semen characteristics of boars used in artificial insemination

Effect of temperature and humidity on sperm production in Duroc boars under different housing systems in Thailand.

Natural Mediterranean photoperiod does not affect the main parameters of boar-semen quality analysis.

Purebred and two-breed cross (F1) boars were mated to F1 females to produce all possible three- and four-breed cross pigs involving the Duroc, Yorkshire, Landrace and Spotted breeds. Individual postweaning average daily gain (ADG), age at 100 kg (AGE) and probed backfat thickness at 100 kg (BF) data were collected on 3,456 pigs. A total of 213 pens with an average of 15.58 pigs per pen was evaluated for postweaning feed-to-gain ratio (F/G) and average daily feed consumption (ADF). Genotype X environment interactions, specifically breed X year-season farrowed and breed X parity (for ADG), were found to be highly significant. Certain results, however, were reasonably consistent across environments. Duroc-sired pigs grew more efficiently than other sire breed groups (3.11 vs 3.21 F/G), although there were no significant differences in ADF between sire groups. Duroc-sired pigs had less BF than other three-breed cross pigs, based upon within breed of dam comparisons, suggesting differences in composition between the more efficient Duroc-sired pigs and other breed groups. Landrace-sired pigs were fatter than other sire groups. No real differences between crossbred-sired pigs and the average of contemporary pure-bred-sired pigs were apparent for F/G, ADF, ADG, AGE, or BF. Assuming paternal heterosis to be zero, these results suggested recombination effects to be negligible for postweaning performance traits. Apart from via direct genetic effects, mating crossbred rather than purebred boars to females of different breeding should have little or no impact on feedlot performance of offspring produced.

/pdf/reproductive-performance-for-four-breeds-of-swine-crossbred-13424eb0sj.pdf

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

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.

Estimates of Heterosis for Sexual Activity in Boars

Crossbred Hampshire–Duroc boars were compared to purebred Hampshire, Duroc and Landrace boars for seven semen characteristics and for reproductive performance under competitive double mating. A total of 14 boars were represented: three Hampshire–Duroc, three Hampshire, three Duroc and five Landrace. Significant breed of boar effects were observed on semen volume (P <.01), sperm concentration (P <.10), concentration score (P <.05), morphology score (P <.10), live–dead rate score (P <.05) and total semen score (P <.01). Landrace and Hampshire–Duroc boars produced more than twice the volume of semen produced by purebred Hampshires and Durocs. Hampshire, Duroc and Hampshire–Duroc boars had greater sperm concentrations and concentration scores than Landrace. Hampshire–Duroc boars ranked highest for morphology and total semen scores, but lowest for live–dead rate score. When double-mated to Landrace sows, breed of boar had no significant effect on conception rate but significantly affected (P <.05) percent of l...

A comparison of crossbred and purebred boars for semen and reproductive characteristics

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A comparison of crossbred and purebred boars for semen and reproductive characteristics