Calves peak-end memory of pain.

In humans, the 'peak-end' rule states that recollection of an experience is most often influenced by the peak (the most intense moment) and end of the experience. We investigated whether calves followed the peak-end rule in their memory of a painful procedure: disbudding. As proxies for retrospective and 'real-time' reports of pain, we used conditioned place aversion, and reflex pain behaviours. In two separate trials, calves were subjected to two disbudding conditioning sessions (one horn per treatment), acting as their own control. In the first trial, calves (n = 22) were disbudded and remained in a pen for 4 h, and disbudded and left in another pen for 4 h with an additional 2 h following an analgesic treatment. In the second trial, calves (n = 22) were disbudded and left in pens for 6 h during both treatments, receiving the analgesic at either 2 h or 4 h after disbudding. Calves were then tested for place aversion. For both trials we did not observe a preference for the pens where calves received analgesic treatment towards the end of the session. We did not find an association between aversion and the sum, peak or end of pain behaviours. Results are not consistent with a peak-end effect in calves' memory of pain.

Hunger affects cognitive performance of dairy calves.

Hunger remains a significant animal welfare concern as restricted feeding practices are common on farms. Studies to date have focused on negative effects on health and productivity but little research has addressed the feeling of hunger, mostly due to methodological difficulties in assessing animals' subjective experiences. Here, we explored the use of a cognitive approach to disentangle motivational hunger (a normal state that is of limited welfare concern) from distressful hunger (a state associated with intense negative emotions). Cognitive performance in a foraging task is expected to follow an inverted U relationship with hunger levels, providing an opportunity to make inferences about different hunger states. We assessed the effect of milk restriction on calf cognition in two experiments using a modified hole-board test. Experiment 1 showed that reducing milk allowance from 12 to 6 l d-1 impaired all measures of cognitive performance. Experiment 2 showed that the same type of feed restriction also disrupted calves' capacity to re-learn. We conclude that hunger associated with reduced milk allowance can disrupt cognitive performance of dairy calves, a result consistent with the experience of distressful hunger.

Assessing cognitive performance in dairy calves using a modified hole-board test.

The hole-board test has been used to assess working and reference memory in a variety of species, but not in cattle. We developed and applied a modified hole-board test for dairy calves. Fifteen bottles were evenly spaced along three walls of a test arena; 11 of these were empty and 4 were 'baited' with milk. Calves were exposed daily (over an 11-day learning period) to the test arena with the location of the baited bottles held constant; the location of the 4 baited bottles was then changed and calves were re-trained on these new locations (over a 7-day re-learning period). Working memory (no. of revisits to the baited set), general working memory (no. of revisits to the whole set), and reference memory (avoidance of non-baited bottles) were assessed daily. Performance significantly improved during the learning period for reference and general working memory. Working memory tended to improve, albeit non-significantly. The change in bottle location initially reduced all performance measures, but these subsequently improved during the 7-day re-learning period. These results indicate that a modified hole-board test can be used to assess calf cognition, and thus may be helpful in future research designed to investigate the effects of housing and rearing conditions on cognition.

Erratum: Hötzel, M.J.; et al. On the Road to End Pig Pain: Knowledge and Attitudes of Brazilian Citizens Regarding Castration. Animals 2020, 10, 1826.

The authors wish to make the following corrections to this paper [...].

On the Road to End Pig Pain: Knowledge and Attitudes of Brazilian Citizens Regarding Castration.

We explored the attitudes of Brazilians towards different methods to deal with boar taint in pork (surgical castration without pain control, SC; surgical castration with pain control, SC+PC; immunocastration, IC; raising entire males, EM). Two surveys (Sv1, n = 441 and Sv2, n = 768) containing closed and open questions were conducted. Nearly 70% of Sv1 and Sv2 participants were unaware that meat of entire males may have boar taint and that SC is widely used in pig production in Brazil. In Sv1, acceptability of SC+PC (63%) and IC (53%) was greater than of SC (15%). In Sv2, acceptability of IC (55%) and EM (52%) was greater than of SC (18%). Open-ended responses indicated that participants objected to inflicting pain to pigs to attain a production goal, and were concerned with organoleptic traits and risks of exogenous residues in pork. Participants' views regarding the potential increases in the cost of meat due to adoption of alternative methods varied; some argued that avoiding pain justifies an increase in the price of pork and others that this would impact especially lower income citizens. Our findings indicate that participants opposed surgical castration without pain control, and supported alternative methods. However, the concern with potential risks of presence of residues in meat, expressed by a few participants, may need to be addressed among consumers.