Play Behaviour In Dairy CalvesTuesday, August 10, 2010
Speaking at the Boehringer Animal Well-Being conference held in Barcelona, Margit Bak Jensen from the University of Aarhus, Denmark looks at play behaviour as an indicator of welfare in dairy calves. Charlotte Johnston, TheCattleSite junior editor reports.
What is play behaviour?
Play behaviour in young animals includes elements of their functional needs, such as flight, fight, sexual and predatory behaviour.
It allows the development of skeletal muscles, modifications of skeletal muscles and the brain, self-assessment of physical and social abilities and training of flexible responses to unexpected events.
Play behaviour in calves may be seen among suckled calves on pasture as they spontaneously start galloping around as a group. Housed in pens calves often buck as a response to provision of fresh straw bedding, or after released from their pens into a novel and large area.
Calf play behaviour includes fast galloping, interrupted by sudden change of direction, bucking, hind leg kicking, body rotations and twists.
This behaviour includes elements of defence and fight, but during play behaviour these elements are exaggerated, repeated and more variable.
Social play includes postures and interactions seen during aggressive interactions, but play does not result in flight or submission.
How can it be used to measure welfare?
Juveniles are motivated to play when their primary needs are met and when they feel no serious threats or challenges. Moreover, the performance of play behaviour is believed to induce positive emotions. Thus play behaviour relates to animal welfare in two ways; by indicating the absence of poor welfare and the existence of good welfare.
How is play behaviour motivated?
Ms Jensen said that previous research looking at the quantity of milk fed to dairy calves showed that dairy calves on an ad libitum diet played more than their peers, on limited amount of milk.
She highlighted that research has shown weaning off milk results in a drop in play behaviour, however only for 24 hours.
The effect of illness on play behaviour has not been fully investigated, however Ms Jensen noted that castration eliminated play behaviour in lambs.
Play behaviour as an indicator of welfare
Ms Jensen's research reached the following hypothesis:
- The absence of motivation to play indicated a state of poor welfare.
- The presence of motivation to play indicates a state of good welfare.
Ms Jensen warned that although presence of motivation to play may indicate that the primary needs of an animal are met, only the performance of play behaviour may be taken as indicative of a positive emotion.
How does the physical environment affect play behaviour
There are two ways that physical behaviour may affect play behaviour. Firstly environmental constraints such as lack of sufficient space, lack of play partners or lack of suitable objects to play with may prevent play behaviour.
Secondly, stimuli in the environment may reduce or increase stimulation to play.
Ms Jensen said that the housing of calves in small individual pens does not allow full social contact and thus prevents the performance of social play.
Her research has shown that space dictates the performance of locomotor play behaviour, as an animal can only move in the space provided.
Studies show that small individual pens limit locomotor play behaviour, whilst group housing will generally give animals more shared space to play.
Increasing the space allowance for group housing doesn't only increase locomotor play but also the general occurrence of play behaviour.
Early on in life, social interaction is much more important for calves, Ms Jensen said. As they grow, space becomes increasingly important to stimulate play.
Developing play behaviour
Ms Jensen questioned whether play behaviour was always a positive welfare indicator?
Play is, by definition, without the function of the original behaviour, however in some reports social play in piglets has ended in fight. In cattle, the tendency for social play to develop into real fights increases as the animals reach maturity, and here it is important to realise at which stage the behaviour may develop into serious interaction.
Ms Jensen says that is may be possible to record play behaviour automatically in the future. An accelerometer attached to the leg of the calf could distinguish between walking, trotting and galloping, as well as counting the number of steps taken in each category.
There is much more scope for the benefits of play behaviour. Little research has been done to see how play behaviour is affected by environmental conditions, such as lighting and temperatures.
Further more there is the scope to see what the economic benefits of play behaviour are, including long term research into weight gains, fertility and milk yields.
Ms Jensen's and others research suggests that play behaviour in juveniles is a indicator of good welfare. Ms Jensen concluded by saying that focus on validation of play behaviour as an indicator of positive emotions in dairy calves, identifying 'play markers' and developing techniques to automatically record play behaviour will allow the industry to relate play behaviour to various housing and management conditions, as well as to health status's on commercial farms.