Reproductive characteristics of feral pigs in New Zealand

Abstract

. 1992. Reproductive characteristics of feral pigs in New Zealand. Acta theriol. 37: 259 -270.Breeding was studied in feral pigs Sus scrofa Linnaeus, 1758 inhabiting the northern part of the South Island, New Zealand. In a sample of 1,117 female pigs 50.4% showed evidence (pregnancy or lactation) that they were breeding. There was no statistically significant regional variation in the breeding status of females. Breeding occurred throughout the year with birth peaks in July-November and March. Among 101 females 5-8 months old, 30 (29.7%) were pregnant. The oldest breeding sow was 14 years old. Breeding females up to 17 months old were significantly heavier than non-breeding females, but the difference ceased to be significant for older animals. Pregnant females averaged 6.2 foetuses (range 1-11). Lactating females had on average 5.4 teats extended (range 1 -12). For areas where pigs are considered a pest species a simulation model predicted a population recovery time of 30 months from a 70% kill.

Reproductive performance of wild boar females in Portugal

“…As suggested by Bouldoire and Vassant (1989), Pavlov (1991) and Dzieciolowski et al (1992), the number of piglets surviving 1-2 months after birth can be estimated from the number of suckled teats, assuming that each piglet uses a single teat exclusively and will defend the teat against other piglets until weaning. Thus, the differences between the observed average litter size and the average number of teats extended would give an estimate of the natural postnatal mortality rate.…”

“…Thus, the differences between the observed average litter size and the average number of teats extended would give an estimate of the natural postnatal mortality rate. Postnatal mortality (PNM) was calculated after Dzieciolowski et al 1992 as follows: PNM=(average litter size−average extended teats)/average litter size×100. This way of access to postnatal mortality is still controversial since other authors reported the possibility that piglets could suck the teats of other females from the group (Hartmuth 1962;Meynardt 1990).…”

“…roe deer Capreolus capreolus, red deer Cervus elaphus), wild boars reach sexual maturity earlier, have a relatively short gestation period, higher litter size and short lactation period (Fernández-Llario and Mateos-Quesada 1998;Gerard et al 1991;Abáigar 1992;Dzieciolowski et al 1992;Gaillard and Jullien 1993;Rosell et al 2001). Sexual maturity in females is achieved between 5 and 10 months of age, although it is assumed that a minimum body weight of 15-35 kg (e.g.…”

Occupancy and habitat use of the endangered Akikiki and Akekee on Kauai Island, Hawaii

“…90 Their populations can quickly rebound, even after being reduced by 40% 91 -70%. 92 Specifications for ungulate removal projects have been approved by the DLNR 93 and partners, 94 which will guide fence construction, ongoing maintenance, and ungulate removal within priority I and II areas. On DOFAW lands, public hunting will be used for the first stage of ungulate removal in fenced areas wherever safe, feasible, and effective, 95 and DOFAW will encourage hunting access in other areas.…”

Habitat and reproductive phenology of wild boar (Sus scrofa) in the western Iberian Peninsula

“…In autumn, females appear to delay the onset of breeding until they attain the threshold weight needed to enter oestrus and they can skip reproduction in years of severe food shortage (Mauget and Pepin 1991;Groot Bruinderink et al 1994). Feral pigs will breed throughout the year, although there are small seasonal peaks in birth frequencies (Barret 1978;Dzieciolowski et al 1992). Pig breeds raised in extensive farming systems, such as the Iberian breed, still retain a seasonal breading pattern showing a lower conception rate in summer (Dobao et al 1983).…”