Management and Genetic Factors Affecting Fertility in Sows

Abstract

Contents The purpose of this article is to summarize the current knowledge on genetic and management methods for improving fertility in sows. Fertilization rate, litter size and the interval between weaning and oestrus are traits that can be monitored on farms. These traits are heritable but can also be influenced by management. Age at puberty and the interval between weaning and oestrus are genetically linked (rg = 0.3) and a shorter weaning‐to‐oestrus interval is related to a longer duration of oestrus. Consequently, selection may be used to simplify detection of oestrus but because of variation in duration of oestrus between lines/breeds, farm‐specific insemination strategies are needed. The direct boar effect on fertilization is small, probably due to the superabundance of sperm cells that is available in each dose of semen. Consequently, the use of a large number of sperm cells per dose is the best management tool for avoiding fertilization problems in sows. Health status of the boars, both for artificial insemination and natural mating, is of importance in order to produce a large number of sperm cells/doses of good quality per ejaculate. It is concluded that factors that influence fertility in sows, particularly prior to and during fertilization, are mainly related to oestrus and the optimal timing of insemination. Selection for adequate symptoms of oestrus, together with farm‐specific insemination strategies are needed.

Variance components and heritabilities for sow productivity traits estimated from purebred versus crossbred sows

“…(2003) of 0.07–0.08 for purebred Landrace and Yorkshire data. All of the above heritabilities for litter size would be considered low as suggested by Merks et al. (2000).…”

Effect of Farm on Productive and Reproductive Performance in Sows of Prestice Black-pied Pig

“…Merks et al (2000) note that the level of farm management can limit the genetic potential of reproductive performance in sows. This is confirmed by Spoolder et al (2009), who state that the overall fertility is influenced by a range of factors, determined by genetics and environmental conditions on the one side, but on the other side it is most frequently expertise -qualification and practical abilities of workers on individual farms, who are responsible for this farming segment.…”

Novel BsuRI-c.930A>G-FSHb Associated with Litter Size Traits on Large White X Landrace Crossbred Sows

“…Nowadays, mean of total number of piglet born is 10.03+2.64 piglets/litter (Imboonta et al, 2007). Litter size is low heritability approximately 0.09 for NBA that affecting slowly changed in genetic drift (Rothschild, 1996;Distl, 2007) and difficult to measure phenotypically by traditional breeding method (Merks et al, 2000). Furthermore, litter size trait is sex-limited and is not measurable until sexual maturity (Spötter and Distl, 2006).…”