Maximum number of total born piglets in a parity and individual ranges in litter size expressed as specific characteristics of sows

Abstract

Background: The objective of this study was to underline that litter size as a key trait of sows needs new parameters to be evaluated and to target an individual optimum. Large individual variation in litter size affects both production and piglet's survival and health negatively. Therefore, two new traits were suggested and analyzed. Two data sets on 5509 purebred German Landrace sows and 3926 Large White and crossing sows including at least two parental generations and at least five parities were subjected to variance components analysis. Results: The new traits for evaluating litter size were derived from the individual numbers of total born piglets (TBP) per parity: In most cases, sows reach their maximum litter size in their fourth parity. Therefore, data from at least five parities were included. The first observable maximum and minimum of TBP, and the individual variation expressed by the range were targeted. Maximum of TBP being an observable trait in pig breeding and management yielded clearly higher heritability estimates (h 2~0 .3) than those estimates predominantly reported so far. Maximum TBP gets closer to the genetic capacity for litter size than other litter traits. Minimum of TBP is positively correlated with the range of TBP (r p = 0.48, r g > 0.6). The correlation between maximum of TBP and its individually reached frequency was negative in both data sets (r p = − 0.28 and − 0.22, respectively). Estimated heritability coefficients for the range of TBP comprised a span of h 2 = 0.06 to 0.10.

The Use of Vagina–Cervix Length Measurement in Evaluation of Future Reproductive Performance of Sows: A Preliminary Study under Commercial Conditions

“…In groups S and M, a significant increase of litter size was noted until the 4th parity and then showed alternate relevant peaks and nadirs. These results are consistent with research conducted by Freyer [26], where the greatest litter sizes were also reached by sows in their fourth parity. On the other hand, some researchers showed that the number of piglets born per litter increases with sows’ parity, reaching a peak between 2 to 5 parities [27,28].…”

Selecting for changes in average “parity curve” pattern of litter size in Large White pigs

“…Despite long‐term selection and high genetic gains achieved already for litter size in pigs, there are no signs of decline in genetic variation and heritability of this trait (Nielsen, Su, Lund, & Madsen, ; Putz, Tiezzi, Maltecca, Gray, & Knauer, ; Trenhaile, Petersen, Kachman, Johnson, & Ciobanu, ; Varona, Legarra, Herring, & Vitezica, ; Zhang et al, ). Still large variation in litter size between sows exists (Freyer, ; Sell‐Kubiak, Wang, Knol, & Mulder, ). In addition, the sizes of the consecutive litters of the same sow also fluctuate, that is, there is a within‐sow variation (Hoving, Soede, Graat, Feitsma, & Kemp, ; Hughes, Wiseman, Varley, Kemp, & Varley, ; Koketsu & Dial, ).…”

Estimation of litter size variability phenotypes in Large White sows

“…Targeting the TNB at a certain optimum rather than continuously increasing, it may be a good approach in terms of litter size variability control. Freyer (2018) reported that sows with litters from 14 to 16 piglets tend to have the smallest variability across subsequent parities. Also, a similar optimum for TNB is expected from the biological point of view, since the number of piglets should not exceed the number of teats (Kim et al, 2005).…”

“…However, both traits must have EVs from a strictly defined and small range to provide a simultaneous change of both traits in the desired directions. Also, Freyer (2018) reported a positive genetic correlation between individual maximum numbers of piglets born and variability of litter size treated as a difference between the maximum and minimum observed litter sizes. However, the opposite sign of the correlation between litter size and its variability was reported in pigs by Felleki et al (2012) and in rabbits by Argente, Calle, Garcia, and Blasco (2017).…”

“…Hence, an increase in litter size results in a simultaneous increase of its variability. The considerable variability of the total number born (TNB) affects profitability of production by increasing costs related to farm management (Freyer, 2018). Also very large litters, which in the Large White pigs could be more than 20 piglets, negatively affect welfare of the animals (Prunier, Heinonen, & Quesnel, 2010; Rutherford et al, 2013).…”