Goats enjoy mental gymnastics

Caption: Goats enjoy the challenge of earning a reward. ©snsf, photographer: Yve

Caption: Goats enjoy the challenge of earning a reward. ©snsf, photographer: Yves Wiesmann

A study on shows that goats like to earn a reward by ’working’ for it, even if they can get the same reward without making any effort. This finding could benefit humane husbandry.

Goats respond positively to challenges rather than just turning away. In a project funded jointly by the Swiss National Science Foundation (SNSF) and the German Research Foundation (DFG), two breeding lines - dairy goats and dwarf goats - were offered a choice of two types of reward. One could be obtained without any effort, while the other had to be earned by opening a door. "In just under half of cases, both breeding lines chose the second option", explain two of the project leaders, Nina Keil, a specialist in proper husbandry, and Katrina Rosenberger, a PhD candidate, both from Agroscope. "In other words they seem to enjoy challenges of this type." The results of their work have now been published in the journal Scientific Reports (*).

Dairy goats surprisingly motivated

The researchers found that both the dairy and dwarf goats willingly took part in the experiment and were motivated to use their muzzles to open a sliding door and obtain a reward. Of the 57 goats that took part, 53 chose to slide open the door to obtain their reward at least one time in ten, even though the same reward could also be obtained without any effort. However, the two breeding lines exhibited different behaviour during the experiment. The dairy goats’ interest in the door was consistent. Overall they were quicker to go to the closed door than to the open one, which could be interpreted as a sign of enhanced motivation. By contrast, the dwarf goats were more cautious in their choice at first, but then increasingly opted for the closed door. This indicates that both breeding lines seem to enjoy solving problems, but that dwarf goats may need more time to adapt to the challenge.

"We had expected the dwarf goats to show interest, since they had already been observed to do so in a similar experiment", explains Katrina Rosenberger in reference to a study carried out at the Leibniz Institute for Farm Animal Biology in Dummerstorf, the project’s German research partner. "However, the dairy goats came as a surprise. Since they are bred for a high milk yield, we had expected them to conserve their energy and be less motivated to make an effort to get a reward, particularly if they could get the same reward without having to make that effort."

Triggering positive emotions

The results are based on the principle of ’contrafreeloading’. "The term describes the behaviour of animals that prefer to make an effort to fulfil their desire for a particular resource rather than have it placed in front of them", explains Nina Keil. The phenomenon has been observed in domesticated animals - cattle, pigs, goats and chickens - and in wild animals in a zoo environment, for example. It is not known whether it also occurs in wild animals outside captivity. "We assume that the animals display this behaviour because solving a task gives them control over their environment and triggers positive emotions", Nina Keil continues. "They apparently derive a certain satisfaction that makes the additional effort worthwhile."

Should domestic goats’ living conditions make allowance for this type of gratification? "Yes, because proper husbandry should take account of the animals’ cognitive wellbeing as well as other needs", says Nina Keil, putting things into context. "Our results are a first step in this direction. Now we need to repeat the experiment over a longer period and under real-life conditions on a farm so that we can see what happens to the animals’ motivation." If the results support the introduction of such measures at farms, it goes without saying that they will have to be easy to integrate into farmers’ everyday routines.

Goats choose between open and closed doors

30 dairy goats bred for a high milk yield (Saanen, Chamois Coloured and crosses of these two breeds) and 27 dwarf goats not bred for productivity took part in the study at Agroscope in Tänikon. The animals had unrestricted access to food to prevent hunger affecting their behaviour during the experiment. In addition, they were accustomed to using their muzzles to open a sliding door from previous experiments. The movement involved reflects goats’ natural behaviour because although the animals graze, they like to browse plants and bushes.

Each goat was placed in a cubicle with access to two openings with sliding doors. One door was open, the other closed, and there was a partition between the two. Behind both doors was a reward in the form of a piece of uncooked pasta. To get to the pasta behind the closed door, the animals had to slide the door open with their muzzle. The closed door was positioned randomly either on the left or the right. Each goat repeated the experiment ten times. The researchers divided the results for each animal into no engagement (if the animal had not gone to either door after 30 seconds), collect reward from behind closed door (in line with contrafreeloading theory) or collect reward from behind open door. They also recorded whether the goats approached the doors quickly or slowly.

(*) K. Rosenberger, M. Simmler, C. Nawroth, J. Langbein, N. Keil: Goats work for food in a contrafreeloading task. Scientific Reports (2020). doi.org/10.1038/s415­98-020-78931-w

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