The activity of Duroc and Pietrain piglets was evaluated based on frequency of their visits to the different compartments of the experimental ground and duration of staying there (Table 1). The analysis of piglets’ activity on frequency of attending the compartments of the experimental ground demonstrates domination of feeding activity (P<0.05). Feeding behavior of Pietrain pigs comprised 80% of total activity, while Duroc pigs feeding behavior comprised 70% of total activity.
The animals spent 5% of their time on consumption of food and water and only 1% of their time at the drinkers (more than 40.0% of all visits). Daily food consumption and the speed of consumption increases with the age of piglets. The speed of consumption might rise up, while the time spend on consumption might be reduced down to 25% (
Gonyou and Lou, 2000). Between the piglets of the two breeds no significant differences were found in relation to average time spent on food consumption. The number of visits to feeders Duroc piglets made in the first four weeks of the experiment was higher than that of Pietrain piglets. Starting from the sixth week of the experiment, however, the attendance of Duroc pigs began to drop while the attendance of Pietrain kept rising. Shortly before the end of the experiment the attendance of feeders by Pietrain was higher. It was connected to the fact that Duroc piglets in the later stages of the experiment were more actively engaged in using toys in B and D compartments, so their interest to feeders as play motivators dropped. Pietrain pigs, in the meantime, were visiting the feeders more often. Despite the fact that during the experiment the feeders were full with food and available to the animals at all times, their number (two) was not enough to eliminate the competition amongst the piglets for feeding spots. Stronger animals pushed away weaker ones, which made the latter to adapt by modifying their feeding regime.
Pigs attended compartment C least of all. Activity according to the duration of staying at the compartments differed from activity according to frequency of visits. It was demonstrated that the piglets stayed longer in the shelter of the compartment C.
Frequency of attending the compartments of the experimental ground and duration of stay were inversely proportional and vary in relation to the goal of each plot and a breed (Table 2).
The total time distribution of Pietrain piglets and Duroc piglets in the compartments of the experimental ground varied significantly. Average time of staying in the compartment with feeders and the compartment with the shelter differed significantly for the breeds (P<0.05). The Pietrain pigs spent less time at the feeders (P<0.05) and 35 % of time more in the shelter, than the Duroc piglets. Animal behaviour within a single functional circle cannot be seen as isolated. On the contrary, various and tight links exist with behaviours from other functional circles and environment
(Bulens et al., 2015). Food consumption and play behaviour are interlinked. After being fed, animals experience an increasing need in play activity. Growing number of visits to the play zone was associated to the growing number of visits to the covered compartment.
Pigs’ needs are irreducible to being fed and provided with conditions for comfortable rest (
Bracke and Hopster, 2006). Exploratory behaviour plays an important role in their activity. It helps them explore a new environment, to navigate there and examine its flexibility. While exploring their environment, pigs acquire up-to-date information about it, which helps them to adapt if the conditions are changing.
The exploratory behavior was accessed by providing the pigs an access to ‘play’ zones equipped with toys. The attendance of the play zone in the experiment was high for the both breeds, but significant differences were revealed between the breeds in the frequency of visits and duration of the stay in the zone (P<0.05). Duroc pigs visited the play zone more frequently and stayed there longer than Pietrain pigs. On average, piglets of the both breeds spent in the play zone 15 minutes.
As other researchers have found, animals kept in an environment, enriched with equipment, stimulating their activity, are more active than animals, kept in an un-enriched environment
(Beattie et al., 2000, Templ and Dalmau, 2011,
Scott et al., 2007). Furthermore, environmental enrichment, introduced in the process of animals’ regrouping, was found to lower the level of aggressive behavior
(Zhuchaev et al., 2011). The elements of environmental enrichment used in this research as play motivators included: a floor mat for grubbing, a straw tanker and balls (Table 3). The data on piglets’ use of play motivators was acquired by direct observation. The piglets were found to dedicate the largest amount of their time to using floor mates (40- 42%) and a straw tanker (24 - 32%). A special attention the animals paid to the floor mates intended to satisfy animals’ needs for grubbing. Providing opportunities for grubbing presents a necessary condition for satisfying the welfare norms in pigs keeping.
The straw bunker was intended to provoke an exploratory behaviour of the piglets. The animals had to put into some effort in pulling out individual straws of the lower holes of the bunker as a prize for their efforts. The affinity of the straw was less than the affinity of the floor mat.
The animals were interested in balls as motivators for play activity only shortly after their introduction in the play zone. Afterwards the animals were losing interest. According to the literature, it can be explained by the fact that a ball as a play motivator fails to offer an opportunity for grubbing
(Blackshaw et al., 1997).
It is known, a backrubber served to satisfy the animals’ need in comfort behavior. The low rate of interest in this motivator (4 - 5% of all visitations) can be explained by the fact that pigs in general are rarely rubbing themselves, but also by the opportunities for rubbing and itching relief presented by other elements of the experimental ground (walls etc.).
Based on the results of the experiment, it can be concluded that the effectiveness of use of different motivators was higher of Duroc pigs than that of Pietrain pigs. Different types of motivators were shown to have a different influence on animals’ activity, and grubbing motivators were preferred.
The experiment revealed the difference in the social behaviour of the pigs. Duroc pigs were more active than Pietrain pigs, showing an aggression 30% more often. The piglets attacked piglets of the same breed as often as they attacked piglets of the different breed. Aggression was mostly observed between piglets of different breeds. Duroc piglets initiated fights more often. Pietrain piglets attacked Durocs piglets rarely and as often as they attacked piglets of their own breed. The piglets touched ears and tails of each other. These contacts did not last long and mainly took place among the piglets of different breeds. No bites were observed during the research.
Fights happened generally in the first days of the experiment. In the later stages of the experiment the frequency of fights lowered, which could be explained by establishment of social hierarchy and introduction of play motivators known to lower the level of aggression of animals. This is in line with earlier findings, that demonstrated that the application of play motivators lowers the frequency of aggressive acts and consequently the level of trauma and livestock loss on farms
(Zhuchaev et al., 2011).
Table 4 represents coefficients of intraclass correlation
rw, which shows the degree of influence of breed on an each type of activity during the separate stages of the research. The statistical significance of the results was accessed by Fisher parameter (F).
The breed influence on feeding activity was established in some stages of the research. In the first stage of the research the breed influence 20% (P<0.05) explained of variance in distribution of feeding activity. On the second and third stages the percentage dropped and started from the 4
th period to rise up to 65% (P< 0.001) on the 6
th period. In general Duroc pigs visited feeders more often (a pig per day: 22.0±3.0), consumed more food per day (1.9±0.3 kg), with higher consumption speed (33.9±5.0 g/min.). Pietrain pigs spent longer at feeders (1.0±0.1 h/day).
The correlation of breed and water consumption and sheltering was demonstrated in the 3
rd and 6
th stage of the research. The correlation of breed and play activity was the strongest, which was supported by direct observation. Duroc piglets were more active, often moved from one compartment to another and more often used play motivators. Pietrain pigs, on the contrary, were more passive, and spent more time lying down. They moved from one compartment to another rarer and on average spent more time in the C compartment with the shelter.
The minimal correlation of breed and play activity was observed in the 2
nd and 6
th stage. On these stages the motivators used were balls and a straw bunker, from which it could we concluded that different motivators had different influence of piglets’ activity. The highest correlation was found in the first period of the research which demonstrates differences in speed of environment familiarization of piglets of different breeds.
