PSII-7 - Assessment of the variation in growth efficiency within Berkshire pigs

Abstract: American Berkshire pigs have a reputation for high quality meat. These characteristics contribute to improved market value, making it an attractive option for value-added pork production. However, variation in growth performance and carcass composition within the breed is not well characterized, and this variation could have a significant impact on producers’ ability to secure premium market value for the end pork product. To investigate this variation, a progeny test of 23 different sires over 3 years, and a total of 200 registered Berkshire progeny from 12 different breeders were evaluated for growth performance differences in average daily gain (ADG), adjusted days to 230 lbs (AD230), and muscle ultrasound measurements (MUM) of loin eye area, marbling, and fat depth. All pigs were housed at the Pennsylvania Department of Agriculture Livestock Evaluation Center, weighed upon arrival, and started on a common, ad libitum finishing ration regimen. Two weeks post arrival, pigs were weighed again, then at monthly intervals until they were sent to market. Shipment dates were determined based on the weights of the pigs, and each shipment took the heaviest 20-30 individuals, regardless of their weight. MUM were taken at the midpoint of the study (July of each year) and within 36 hours of shipment on all pigs during years 2 and 3 of the study. Progeny arrived to the test averaging 49.41 lbs (± 22.89 lbs), and 66.7 days old (± 17.7) over the 3 years of the test. Growth from placement to marketing, averaged 1.70 lbs/d (P ≤ 0.01). Variation was observed between Group, Breeder, and Sire for AD230 and MUM. The AD230 averaged 189 days across all pigs; when comparing across breeders, the AD230 ranged from 228.5 days for the slowest growing pigs to 154.9 days for the fastest growing pigs. Differences across Group, Breeder, and Sire persisted in MUMs, with loin eye area increasing 1.3 sq. inches from midpoint to marketing. These findings reflect the characteristics observed in growth and MUM for American Berkshire pigs across 8 states. While the variation in this group is significant, the testing conditions were consistent and provide an understanding of the variation in growth performance within the Berkshire breed. Ultimately, this data provides essential information to new and existing pig producers to inform their breed selection and production decisions to reach their market goals.