By USDA NAHMS - The USDA’s National Animal Health Monitoring System (NAHMS) collected data on swine health and management practices from a random sample of swine production sites in 17 states 1 as part of the Swine 2000 study. These sites represented 94 percent of the U.S. pig inventory and 92 percent of U.S. pork producers with 100 or more pigs. This article reports on the study's findings on Mating Procedures.

Overall, 2,499 swine production sites participated in the first interview from June 1, 2000, through July 14, 2000.

For estimates in this report, small, medium, and large sites refer to sites with less than 250, 250 to 499, and 500 or more breeding females, respectively. Animal-level estimates reported here are based on a June 1, 2000, inventory.

Swine Mating Practices

Reproductive performance is an integral part of porkproduction. Farrowing rates and litter size can beaffected significantly by mating practices; therefore,proper mating techniques are essential for optimumreproductive efficiency.

Often, breeding females are mated more than onceduring their estrous cycle/heat period. The studyindicated that the majority of sows (50.9 percent) andgilts (47.3 percent) were mated twice during anestrous cycle (Figure 1). More than one-fourth of allsows and gilts were mated three or more times perservice.

Mating techniques used to breed sows and gilts variedby size of site. Pen-mating was used most commonlyon small sites (84.4 percent), compared to large sites(6.4 percent). Artificial insemination was used formating sows and gilts on 91.3 percent of large sites(Figure 2).

Although artificial insemination was used on only23.2 percent of all sites, more breeding females werebred using artificial insemination than any othertechnique because more large sites (91.3 percent) usedthis technique than medium (61.4 percent) or small(12.1 percent) sites. Overall, 68.6 percent of sows and64.5 percent of gilts were on sites where artificialinsemination was the predominant mating techniquefor the first mating. Similarly, 72.3 percent of sowsand 65.7 percent of gilts were on sites where artificialinsemination was the predominant mating techniquefor the second mating (Figure 3).

Semen was purchased by 72.9 percent of sites thatused artificial insemination. Only 17.1 percent of sitesusing artificial insemination actually collected andprocessed semen on-site. Semen was collected andprocessed off-site (e.g., owner, boar-stud) by 20.8percent of sites using artificial insemination. (Note:some sites obtained semen from multiple sources;therefore, the values mentioned above sum to morethan 100 percent). More sites in the Southern regioncollected semen off-site than did sites in the WestCentral, Northern, and East Central regions(Figure 4).

Sites that used artificial insemination as thepredominant mating technique averaged 10.7 totalpigs born per litter, compared to 9.9 total pigs bornper litter for sites using other techniques. Thepercentage of breeding females culled for reproductivefailure was higher on sites where artificialinsemination was the predominant mating technique(23.3 percent of culls), as compared to othertechniques (15.8 percent of culls).

Breeding records were kept by over three-fourths ofsites with gestation and farrowing phases. Theserecords were kept more often on large (96.8 percent)and medium (96.3 percent) sites than on small sites(72.2 percent).

Although 78.1 percent of sites were visited by aveterinarian during the previous 12 months, only 7.1percent of these sites used a veterinarian for artificialinsemination or breeding evaluations. Generally, aveterinarian was used more often for artificialinsemination and/or breeding evaluations as site sizeincreased (5.3 percent of small sites; 28.7 percent ofmedium sites; and 42.7 percent of large sites).

All the Reports in the Series (to date)