The U.S. Department of Agriculture (USDA) has released the third part of its Swine 2000 report.

USDA's National Animal Health Monitoring System (NAHMS) surveyed producers in 17 states in 2000. Small sites were less than 2,000 head; medium sites, 2,000 to 9,999 head; and large sites, 10,000 or more pigs.

Survey highlights showed:

  • The annual removal rate of breeding age females from death loss and culling was 45.9%.

  • An average of 10.9 pigs born/litter, 10.0 pigs/litter born alive, and 8.8 pigs/litter weaned.

  • A higher percentage of pigs died in grow-finish (3%) than in nurseries (2.4%).

  • Only 25% of small sites kept birds out of swine facilities, compared to more than 85% of large sites.

  • About half of sites using rodent baits outside gestation buildings placed baits more than 50 ft. apart, too far apart for effective rodent control.

  • Hog enterprises had these animals on their premises: cats, 73.1%; dogs, 70.9%; and cattle, 51.7%.

  • Nearly 60% of operations in the southern region reported having wild hogs in their county, compared to less than 6% elsewhere.

  • The three top sources of food safety information were: veterinarians, 76.1%; industry magazines, 71.9%; and industry programs, 69.7%.

  • Lagoons were used on 75.4% of southern region sites, 42.6% of west central sites and less than 20% of sites in northern and east central regions.

  • More than 90% of large sites had formal, written nutrient management plans; less than 20% of small sites did.

  • Irrigation was the most common means of manure application in the southern region.

  • Small sites most commonly applied solid manure using broadcast spreaders; medium-sized sites spread slurry by surface or subsurface injection; and large sites disposed of liquid manure by irrigation.

  • To control hog odor, 50.2% of sites used diet manipulation, 28.9% used manure management and 28.2% used air quality methods. Just 3.6% of sites used chemical additives, while 12.4% of sites used biological additives.

Feeding Practices

During grow-finish, 24.0% of sites fed two different diets, 26.2% fed three and about 40% fed four or more rations.

More large- (45.6%) and medium-sized (56.0%) sites practiced split-sex feeding than did small sites (15.2%).

While the percentage of small- and medium-sized sites using split-sex feeding has remained fairly constant since the 1995 NAHMS swine survey (14.0% and 55.4%, respectively), the percentage of large sites using this practice has plummeted from 78.2% of sites in 1995.

NAHMS analysts suggest this decrease may be due to leaner genetics, difficulty of use on large sites or lack of economic benefit.

During the six months prior to the Swine 2000 survey, antibiotics were included in 88.5% of diets for grow-finish pigs. Antibiotics treated respiratory problems on 27.4% of sites, enteric diseases on 15.2% of sites and were used for growth promotion on 63.7% of sites.

Feed-related intervention strategies can be used to reduce salmonella shedding by grow-finish pigs. Withdrawal of feed before shipping to slaughter was done on 3.2% of sites and testing feed for salmonella on 1.7% of sites.

Mating Practices

Breeding females are often mated more than once during their estrous cycle (Figure 1), according to the NAHMS report. Nearly 51% of sows and 47.3% of gilts were mated twice and a fourth three or more times.

Artificial insemination (AI) was the breeding method of choice on 91.3% of large sites, pen mating on most (84.4%) small sites (Figure 2).

Semen was purchased by 72.9% of sites that used AI, leaving only 17.1% of sites using AI actually collected and processed on-site.

Sites using AI as the main means of mating averaged 10.7 total pigs born/litter, vs. 9.9 total pigs born/litter for sites using other techniques.

For more information on the report, contact Eric Bush, DVM, at (970) 494-7000; e-mail or log on to