The Behaviour of Stallions in a Semiferal Herd in Iceland: Time Budgets, Home Ranges, and Interactions

A permanent herd of Icelandic horses with four stallions and their harems was studied for a total of 316 hours in a large pasture (215 ha) in May 2007 in Iceland. Interactions between stallions of different harems and other aspects of the horses' behaviour were studied. One stallion and nine horses were introduced into the pasture prior to the study to examine the reactions of the resident stallions to a newcomer. The stallions spent significantly less time grazing than other horses and were more vigilant. Home ranges overlapped, but harems never mixed. The stallions prevented interactions between members of different harems indirectly by herding. Generally, interactions between resident stallions were nonviolent. However, encounters with the introduced stallion were more aggressive and more frequent than between the other stallions. Here, we show that four harems can share the same enclosure peacefully. The social network seems to keep aggression at a low level both within the harems and the herd as a whole. We encourage horse owners to consider the feasibility of keeping their horses in large groups because of low aggression and because such a strategy gives the young horses good opportunities to develop normally, both physically and socially

Food Aversion Learning in Lambs with or without a Mother: Discrimination, Novelty and Persistence

The livestock industry suffers substantial losses from animals eating poisonous plants. Research on learned food aversions will enhance understanding of the abilities of livestock to detect and avoid toxic foods. This study sought to determine: (1) whether lambs and ewes can be aversively conditioned to avoid palatable foods; (2) whether learned aversions persist; (3) whether aversive conditioning affects how lambs and ewes respond to novel food; (4) the influence of the mother on the lambs\u27 learned food aversions. The results clarified several points. (1) The treatment group of sheep learned to avoid rolled barley (RB) and rabbit pellets (RP) containing 2% lithium chloride (LiCl), a non-lethal gastrointestinal poison. However, they always sampled small amounts of RB and RP that contained LiCl, and increased consumption when foods no longer contained LiCl. Conversely, the control group of sheep accepted RB and RP containing 2% sodium chloride (NaCl) and increased the amount ingested during each exposure. Alfalfa pellets, the basal diet, were consumed readily and entirely by treatment and control groups throughout the study. (2) Learned aversions persisted for at least 60 days. (3) Treatment and control animals ingested small amounts of RB and RP when they were novel foods. Poisoning made ewes and lambs, but not orphans, more neophobic than unpoisoned sheep. Ewes spent less time at food boxes than lambs, suggesting that poisoning made ewes more neophobic than lambs. (4) Lambs separated from their mothers spent less time at food boxes than orphaned lambs, but both groups ate the same amount. That sheep learned about the consequences of ingesting foods and that they remembered for at least 60 days is evidence that diet selection can be manipulated. If sheep have an inherent tendency to sample noxious feeds, however, they will avoid particular foods only if they are always noxious. Conversely, if the sampling behavior of sheep was an artifact of the procedures and sheep can be conditioned to avoid totally a particular food, it will be feasible to train sheep to avoid foods such as poisonous plants. Further research is necessary to clarify this aspect, to more fully elaborate the learning abilities of sheep, and to assess the implications for management

The Role of the Mother in the Intake of Harmful Foods by Lambs

In two experiments, we studied whether a conditioned food aversion in the mother affected intake of the same food by her lamb in the absence of the mother. Mothers averted to a palatable food ate very little of the food in the presence of their lambs during the 4-day exposure in Experiment 1 and the 5-day exposure in Experiment 2. In Experiment 1 the feeding behavior of mothers during exposure did not (P\u3e0.05) affect the intake of novel foods by lambs during the 10-day trial after weaning. However, in Experiment 2 lambs exposed with averted mothers ate less (P=0.001) of the food (16 g per day) than lambs whose mothers ate the food in their presence (80 g per day) during an 8-day trial after weaning. Results persisted during an 8-day trial 3 months later. Differences in ages of lambs and exposure procedures may have caused different outcomes in Experiments 1 and 2. In Experiment 1, lambs were \u3e 11 weeks of age during exposure, while in Experiment 2 they were 8 weeks of age. Moreover, mothers and treatment lambs in Experiment 1 were given the experimental and the alternative food simultaneously during the 4-day exposure, while in Experiment 2 mothers and lambs were given only one food at a time during the 5-day exposure