Reproductive performance of wild boar females in Portugal

Abstract

Reproductive tracts of 214 female wild boars collected in Central Portugal between October and February over the period 1997 to 2001 were examined. From this material, we were able to determine reproductive phenology (conception and birth periods) as well as age and weight of sows at puberty, ovulation rates of adults, foetal sex ratio, levels of intrauterine mortality, final litter size and postnatal mortality. Differences between year, region, age and body weight were analysed. A total of 66.8% of the females examined were gestating or lactating and 96.3% of these weighed >40 kg. The highest proportions of pregnant sows were found in the adult age/weight classes (74%). None of the juvenile females (1 year old and younger) were lactating and only 7% was pregnant. The average number of foetuses/female (4.1±1.2SD) and that of corpora lutea per female (4.6±1.7SD) increased from lighter and younger to heavier and older wild sows. Foetal sex ratio was biased towards males (1.3:1). Observed intrauterine mortality rate (9.7%) and postnatal mortality (6.3%) were among the lowest recorded in European wild boar populations. The productivity rate of the Central Portuguese wild boar population was calculated as 1.1 young per individual in the population. Conception and birth periods did not differ significantly between the considered 4 years. Birth synchronisation was pronounced in all the years, with a peak of births occurring in March.

The effect of selected environmental Fusarium mycotoxins on the ovaries in the female wild boar (Sus scrofa)

“…At that time, the proliferation process slows down and apoptosis is enhanced, i.e. there is a negative correlation between ZEN concentrations and ovulatory activity because anoestrus in female boars is generally observed in spring and summer (Fonseca et al 2011). After farrowing, mothers have to feed their offspring at a time when food is scarce, at least in the initial period.…”

The influence of environmental and physiological factors on the litter size of wild boar ( Sus scrofa ) in an agriculture dominated area in Germany

“…Several studies found a positive relationship between female age or body weight and the number of foetuses per female (Aumaître et al, 1982;Fernández-Llario et al, 1999;Fonseca et al, 2011). Also environmental factors (weather conditions and food resources) influenced the reproduction of wild boar (Bieber and Ruf, 2005;Fernández-Llario and Mateos-Quesada, 2005;Geisser and Reyer, 2005).…”

“…It shows sexual size dimorphism (Focardi et al, 2008) and a low natural adult mortality rate in temperate climes (Keuling et al, 2013a), which is typical for Kstrategists. On the other hand, it has by far the highest reproductive potential and fecundity of all ungulate species world-wide in relation to its body mass (Boitani et al, 1995b;Focardi et al, 2008;Fonseca et al, 2011;Gaillard et al, 1993;Servanty et al, 2009), so that it can reach high population densities within a very short time period (Geisser and Reyer, 2005). Additionally, it is also an opportunistic omnivore with a high adaptability to changing environmental conditions (Baubet et al, 2004;Gamelon et al, 2013;Schley and Roper, 2003;Servanty et al, 2011).…”

African swine fever

“…Moreover, hunting and trapping could lead to adaptation of wild boar behaviour, for instance by becoming more active during the night, increased home range sizes (Calenge et al, 2002;Sodeikat and Polheimer, 2002;Scillitani et al, 2010) and/or increased reproduction (Bieber and Ruf, 2005;Hanson et al 2009;Gamelon et al, 2011;Servanty et al, 2011). In addition, an increase in effort is required to hunt or trap wild boar when the animal density reduces (Cruz et al, 2005), but maintaining an intense hunting or trapping pressure during several seasons could be difficult for practical and/or social reasons (Fonseca et al, 2011;Boadella et al, 2012). No papers could be found which reported the time period over which population reductions could be maintained in Europe.…”