19/10/2020
The number of animals on a livestock export ship is determined by strict regulation, but there is little scientific understanding of the impact of density on behaviour, how animals use the space they have, or their overall health, welfare and performance.
Despite the cliché of ‘flock mentality’, a trial has found that it is uncommon for sheep housed in groups sized from 20 to 100 to all sit or lie down at the same time.
It’s the first phase of research into stocking density under the Livestock Export RD&E Program’s strategic four-year partnership with the University of New England (UNE).
The first stocking density experiment was designed to observe and record the behaviours sheep display and analyse their frequency in a controlled environment when the animals are given ample space, and housed in different group sizes.
It involved Merino wethers aged 24-36 months, and was conducted over 50 days during summer in an enclosed shed located at one of the UNE SMART Farms ‘Kirby’ near Armidale in northern New South Wales, with animal ethics approval.
The pen space was big enough for all animals to lie down simultaneously and have access to feed and water at all times. The study examined whether group size had an effect on the behaviours of sheep, including whether they were more or less likely to synchronise their behaviour, and how the frequency of collecting data affected the ability to detect behaviours.
Cameras installed above the pen floor allowed continuous monitoring of all sheep simultaneously. UNE is working with the University of Technology Sydney (UTS) to develop computer algorithms to detect standing and lying behaviour, to increase the understanding of how animals use space and allow researchers to be more time efficient when analysing video footage.
Researchers found it was rare for 100% of sheep to lie down to rest or sleep at the same time. For example, in the group of 100, out of 1906 observations where at least one animal was lying down, there were only three times where all 100 sheep were lying down.
However, further research is required to determine the most common pattern of group synchronicity for lying in housed sheep. This study concluded that groups of 20 sheep would be representative of standing and lying positions in larger groups of sheep for future trials.
Following on from this first experiment, researchers will test the effect of additional stressors on sheep welfare.
A new experiment is investigating the effect of stocking density and restricting trough space on group behaviours (including simultaneous lying), and the welfare of sheep. This will provide important and applicable information about how animals utilise space, and the optimal stocking density to minimise impact on animal wellbeing. It is applicable not only the livestock export industry but other situations where livestock are intensively housed such as scientific housing, feedlots and saleyards.
Separately, researchers are assessing faecal pad formation and ammonia production during simulated voyage conditions over a 21 day period, similar to a sheep voyage to the Middle East, under differing stocking densities. This will provide a base understanding for future experiments where researchers will then incorporate conditions such as varying airflows, dietary protein levels and simulated climatic conditions.
Ammonia from animal manure can impact animal welfare, health and performance outcomes in confined spaces, and the aim of the research is to help exporters to identify risks for pad condition deterioration and high ammonia concentrations, and better plan to mitigate these during sea voyages.
Practical recommendations will be developed for industry on the dietary, airflow, and bedding management practices required to confidently predict and manage undesirable pad moisture and ammonia conditions, to improve animal health and welfare.