Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 9 uppsatser.

The resource requirements and social behaviour of pigs housed in large groups were examined in a series of experiments. (i) The nipple drinker requirement was addressed by using four treatments (60 pigs, 3 drinkers; 20 pigs, 1 drinker; 60 pigs, 6 drinkers and 20 pigs, 2 drinkers). Drinker provision had no effect on water use, but in a larger group more water was used in less time (p<0.001). The diurnal pattern of drinking, overt aggression and lesion score indicated no difference between treatments. (ii) Pigs, housed on deep straw in groups of 20 or 80, were provided with a low (50<I> </I>kg/m²) or high (32 kg/m²) floor space allowance. Large groups had a lower growth rate. Skin lesions were elevated and immune response was lowered by a low space allowance. (iii) Two feeder space allowances (32.5<I> </I>and 42.5<I> </I>mm/pig) for pigs housed in groups of 20 or 80 were investigated. Food intake was lower in the low feeder allowance treatments and pigs in large groups tended to have a reduced growth rate. (iv) Pigs from the same pen in an unfamiliar arena maintained a similar degree of proximity regardless of origin group size. (v) Pigs from groups of 80 demonstrated reduced aggressiveness (increased latency to fight, decreased rate of aggression) towards unacquainted pigs in an arena, but showed even less aggression towards pen mates. (vi) No evidence of spatial sub-division of the large group into smaller units capable of maintaining a dominance hierarchy was found. Resource provision and group size largely did not interact, but may independently compromise productivity and behaviour. A large group was associated with a reduction in performance. The dominance hierarchy was of less importance in large groups, despite recognition being intact, and sub-grouping behaviour did not provide an alternative strategy for group social organisation.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 10 uppsatser.

Diss. (sammanfattning) Stockholm : Karol.inst. / Härtill 7 uppsatser.

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2010. / Härtill 5 uppsatser.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

No description available.

Thesis (Ph. D.)--University of Pennsylvania, 1929. / "Reprints from the Journal of comparative psychology, vol. VIII, no. 5 and vol. IX, no. 4."

The behavioral responses of lynx (Lynx canadensis) to declines in snowshoe hare (Lepus americanus) abundance were examined in the southwestern Yukon. Between April 1982 and June 1984 11 lynx were radio-tagged and monitored within and near the Kluane Game Sanctuary. Lynx mean home range size increased from 13.2 to 39.2 km² concurrent with a decline in snowshoe hare abundance from 14.7 to 0.2 hares/ha. Below about 0.5 hares/ha several lynx abandoned their home ranges and became nomadic, although they remained within the general study area. Track transects through areas known to have different snowshoe hare densities indicated that, lynx concentrated their foraging efforts in areas of relatively high snowshoe hare abundance. Lynx abandoned these areas after hare abundance declined. Lynx foraging effort in terms of distance travelled per day showed a curvilinear relationship to snowshoe hare abundance. Straight-line daily travel distance remained constant at 2.2 to 2.7 km/day above 1.0 hare/ha. Below 1.0 hares/ha, straight-line daily travel distances increased rapidly, reaching 5.5 km/day at 0.2 hares/ha. Three of 7 radio-tagged lynx dispersed 250 km or more from the study area during the period of rapid decline in hare abundance in 1982. No similar long distance dispersal was recorded after hare densities stabilized at less than 1.0 hares/ha. Trapping mortality was responsible for the loss of 7 of 9 radio-tagged lynx that travelled outside the game sanctuary. One lynx died, and is believed to have starved, during the winter or spring of 1984. The high rate of trapping mortality outside the game sanctuary suggests that refugia in wilderness areas are important in maintaining lynx populations during periods of low recruitment. / Science, Faculty of / Zoology, Department of / Graduate