Bob Kemp, Vice President Genetic Programs and R&D
The contribution of colostrum intake to survival and development of young pigs has been known for many years. More recent research has demonstrated the importance of sufficient colostrum intake on reproductive performance. Sows that had low colostrum intake on day 1 of life took longer to reach puberty, produced fewer piglets born alive, produced litters with lower average colostrum intake and slower pre-weaning growth rate (1). Colostrum intake has also been associated with testicular development and reproductive success of boars (2). Clearly colostrum intake is important for piglets to survive and thrive but also their future production. As pointed out in a recent article (3) the question is can we genetically enhance colostrum production?
Sow colostrum production is difficult to accurately measure and thus estimation methods currently focus on indirect measurements based on individual piglet colostrum intake. Two methods of estimating piglet colostrum intake are piglet weight gain on day 1 of life (weighing individual piglets at birth and 24 hours later) or analysing blood samples collected on each piglet at the end of day 1 of life. Then sow colostrum production is estimated as the sum of the piglet intakes. Measuring a large number of litters is important for genetic evaluation. Thus, current methods require measuring all piglets in many litters on day 0 and/or day 1. Both methods assume that they accurately reflect sow colostrum production and require substantial additional labour, making practical application in a genetic improvement program very difficult.
An alternative approach to improve sow colostrum production is to use easily-measured traits that are heritable and genetically correlated to colostrum production (3). One such trait teat number. It is common to select for more total teats. The logic being that with more teats, more piglets can nurse individual teats for the first 24 hours and more colostrum will be available for each piglet. However only functional teats produce colostrum and milk. Total number of teats and number of functional teats have similar heritability (4) and thus will respond to selection similarly. Selecting for total number of teats will increase the number of functional teats but will also increase the number of non-functional teats. Selection to increase the number of functional teats will decrease the number of non-functional teats. Increasing the number of teats will also increase body length and increased body length has been identified as a predictor of reduced sow longevity (5). How much of this effect is under genetic control is not known. However, compared to selection for number of functional teats, selection for total number of teats (functional plus non-functional) will result in more total teats and could result in an undesirable correlated response of reducing sow longevity. Other research has shown that increasing the number of functional teats will increase piglet survival and total litter weight (6). The Genesus genetic improvement program counts the number of functional teats at farrowing, calculates a Genomic Estimated Breeding Value (GEBV) as part of our maternal evaluation and includes the GEBV in the maternal indexes with positive emphasis to increase the number of functional teats.
Gilts with higher levels of colostrum intake on day 1 have been shown to reach puberty faster than gilts with lower colostrum intake (1) and sows with a younger age at puberty had increased colostrum production and increased piglet colostrum intake (7). Thus, reducing age at puberty can affect colostrum production. At Genesus we measure age at first farrowing under constant management practices and use this trait as an indicator of age at puberty since precise measurement of age at puberty is difficult. The GEBV for age at first farrowing is also included in our dam line index with appropriate pressure to reduce the age at first farrowing or puberty.
Average piglet colostrum intake, up to approximately 550 to 600 grams has been shown to have a positive impact on piglet survival and litter weaning weight. The average colostrum intake is generally below this level and was 467 grams in a recently published article. Thus, selection to increase both litter weaning weight and piglet survival will provide another indirect way to increase sow colostrum production (3). At Genesus we measure litter weaning weight and total piglet mortality (birth to weaning) at each parity, produce GEBVs for both traits and include them in our selection index to enhance litter weaning weight and piglet survival.
At Genesus, providing genetics that increase customer profitability is the goal of our genetic improvement program. Enhancing sow colostrum production has been shown to maximize pig throughput and profitability (3). While direct measurement of a sow’s colostrum production is difficult, improvement of this important trait can be accomplished by including traits in the genetic improvement program that are indirectly associated with colostrum production. Genesus includes several of these key traits (litter weaning weight, piglet survival, number of functional teats and age at first farrowing) directly in our selection indexes for both of our maternal breeds. The relentless focus on continuous genetic improvement of profitability is a key feature for Genesus customers.
References
- Vallet et al. 2015. J. Anim. Sci. 2015.93:2722–2729. doi:10.2527/jas2014-8535
- Rahman et al. 2014. Domest. Anim. Endocrinol.48:84-92. https://doi:10.1016/j.domaniend.2014.02.006
- Knauer, M. and Wiegert, J. 2023. National Hog Farmer September 7, 2023 https://www.nationalhogfarmer.com/livestock-management/does-the-modern-sow-produce-enough-colostrum-
- Earnhardt-San et al. 2023. Animals 13(15), 2400; https://doi.org/10.3390/ani13152400
- Bender Bartholomew, JM. 2022. PhD. Dissertation, North Carolina State University, Raleigh. NC https://repository.lib.ncsu.edu/bitstream/handle/1840.20/40121/etd.pdf?sequence=1&isAllowed=y
- Weigert, J and Knauer, M. 2018. J. Anim. Sci. 96 (Suppl. S2):51-52. https://doi.org/10.1093/jas/sky073.096
- Wiegert et al. 2018. J. Anim. Sci.96 (Suppl. 2):80. doi:10.1093/jas/sky073.148
