Opportunities (and challenges) in dairy cattle cognition research: A key area needed to design future high welfare housing systems

The ability of dairy cattle to adapt to husbandry systems and management routines is crucial for ensuring higher welfare and efficient production. However, this ability can be compromised by our limited knowledge of their cognitive abilities, which may result in suboptimal husbandry and management standards. In this narrative review, we highlight three topics of cattle cognition research that are currently understudied, and yet key to developing future high welfare dairy cattle housing systems: 1) transmission of information from cow to calf, 2) mechanisms to attenuate fear, and 3) cognitive processes involved in the human-cattle relationship. We review the currently available literature on all three topics and highlight promising research areas from an animal husbandry point of view. We conclude that future studies should focus on elucidating what, and how much, calves learn from their dam during prolonged cow-calf contact in dairy cattle systems. Such information could constitute an important part of the discussion of whether to keep cows and calves together for a longer time after calving in the dairy industry. Fear in the cattle group might be lowered by the use of calm companions and future studies could uncover if attenuation of fear might even be induced by conditioning positive experiences of cattle with unrelated stimuli such as odours. Lastly, the human-cattle relationship might benefit from utilising the already established training regimes from other species, for example positive reinforcement training or target training, which may have the potential to decrease risk of injury during handling for both the cow and the handler

A calm companion lowers fear in groups of dairy cows

Dairy cows are generally calm and compliant, but some management procedures can make cows fearful or stressed. Not only are fearful cattle a threat to human safety, but fear is also detrimental to animal welfare and productivity. This study aimed to test whether fear in small groups of dairy cattle could be attenuated by the presence of a calm and experienced companion. Twenty-seven dairy cows from a Swedish agricultural school participated in the study. The study included a standardized fear-eliciting stimulus, which was 3 sudden, repetitive openings of a red and white umbrella. Demonstrator cows (n = 9) were selected based on age to ensure that all demonstrators were older than the naïve test cows (n = 18). Of these 9 demonstrator cows, 6 were selected as untrained (i.e., habituated to the presence of the test person) and 3 were selected as trained demonstrators (i.e., additionally habituated to the fear-eliciting stimulus). The remaining 18 test cows comprised 6 test-cow groups of 3 cows each, which were their own controls, resulting in a crossover design; 3 groups were tested with a trained demonstrator first and then with an untrained demonstrator, and vice versa for the other 3 groups, resulting in a total of 12 trials (4 sub-treatments). Response variables were heart rate increase from baseline, behavioral reaction indicative of fear, and latency to resume feeding after exposure to the fear-eliciting stimulus. The study found a calming effect of a trained demonstrator on test cows' heart rate but not on latency to resume feeding or behavioral reaction. Post hoc analyses revealed a carryover effect on latency, indicating that test cows who were accompanied by an untrained demonstrator first had longer latencies than cows in all other sub-treatments. Adding a calm, experienced cow to groups of dairy cattle may mitigate fear and thereby improve welfare and safety

Horse odor exploration behavior is influenced by pregnancy and age

In spite of a highly developed olfactory apparatus of horses, implying a high adaptive value, research on equine olfaction is sparse. Our limited knowledge on equine olfaction poses a risk that horse behavior does not match human expectations, as horses might react fearful when exposed to certain odors, which humans do not consider as frightening. The benefit of acquiring more knowledge of equine olfaction is therefore twofold; (1) it can aid the understanding of horse behavior and hence reduce the risk of dangerous situations, and (2) there may be unexplored potential of using odors in several practical situations where humans interact with horses. This study investigated behavior and olfactory sensitivity of 35 Icelandic horses who were presented with four odors: peppermint, orange, lavender and cedar wood in a Habituation/Dishabituation paradigm. The response variables were sniffing duration per presentation and behavioral reaction (licking, biting, snorting, and backing), and data were analyzed for potential effects of age, sex and pregnancy. Results showed that habituation occurred between successive odor presentations (1st vs. 2nd and 2nd vs. 3rd presentations: P P P P = 0.0068). Pregnant mares sniffed odors less than non-pregnant mares (P = 0.030), young horses (age 0-5 years) sniffed cedar wood for longer than old horses (P = 0.030), whereas sex had no effect (P > 0.050). The results show that horses’ odor exploration behavior and interest in odors varies with age and pregnancy and that horses naïve to the taste of a substrate, may be able to link smell with taste, which has not been described before. These results can aid our understanding of horses’ behavioral reactions to odors, and in the future, it may be possible to relate these to the physiology and health of horses

Dairy cows did not rely on social learning mechanisms when solving a spatial detour task

As herd-living animals, cattle have opportunities to observe and learn from others. While there is evidence of simpler processes of information transfer in cattle (social facilitation and stimulus enhancement), true social learning mechanisms in cattle remain largely unexplored. This study aimed to investigate if dairy cows possess cognitive abilities to acquire new behavior through social learning in a spatial detour task. Thirty-two dairy cows (ages 2-9 years) participated in the study. A food reward was placed behind a U-shaped formation (4x2 m), allowing the cows to see but not reach the reward without first detouring around the obstacle. The U-shape provided two routes (approx. 18 m walking distance) to the reward, of which one was used for demonstration. Two cows were demonstrators and 30 cows were divided into two groups, assigned as either observers of demonstration (n=15) or controls not observing demonstration (n=15). Cows had three attempts (trials) to solve the task. Response variables were: success, latency to reach the reward, concordance in choice of route to detour, and time spent facing the test arena before each trial started. The study found no significant differences in success or latency between observers and controls, although observers spent a greater proportion of the time before trials facing the test arena. However, successful observers tended to be faster than successful controls. Individual cows were generally consistent in their choice of route, and cows choosing the demonstrated route were significantly faster than cows that did not. Success in solving the task decreased over trials, likely due to decreasing food motivation. Age had a significant effect on success in 2nd and 3rd trials, with younger cows being more successful. The lacking effect of treatment on success suggests that the age effect may be explained by a higher motivation, rather than social learning. Adding to the sparse knowledge of social learning in farm animals, these results indicate that cows did not utilize social learning mechanisms when solving the detour task. Future research should focus on clarifying whether cattle possess cognitive abilities necessary for social learning, as well as if /when social learning is a primary strategy

Horse odor exploration behavior is influenced by pregnancy and age

In spite of a highly developed olfactory apparatus of horses, implying a high adaptive value, research on equine olfaction is sparse. Our limited knowledge on equine olfaction poses a risk that horse behavior does not match human expectations, as horses might react fearful when exposed to certain odors, which humans do not consider as frightening. The benefit of acquiring more knowledge of equine olfaction is therefore twofold; (1) it can aid the understanding of horse behavior and hence reduce the risk of dangerous situations, and (2) there may be unexplored potential of using odors in several practical situations where humans interact with horses. This study investigated behavior and olfactory sensitivity of 35 Icelandic horses who were presented with four odors: peppermint, orange, lavender and cedar wood in a Habituation/Dishabituation paradigm. The response variables were sniffing duration per presentation and behavioral reaction (licking, biting, snorting, and backing), and data were analyzed for potential effects of age, sex and pregnancy. Results showed that habituation occurred between successive odor presentations (1st vs. 2nd and 2nd vs. 3rd presentations: P < 0.001), and dishabituation occurred when a new odor was presented (1st vs. 3rd presentations: P < 0.001). Horses were thus able to detect and distinguish between all four odors, but expressed significantly longer sniffing duration when exposed to peppermint (peppermint vs. orange, lavender and cedar wood: P < 0.001). More horses expressed licking when presented to peppermint compared to cedar wood and lavender (P = 0.0068). Pregnant mares sniffed odors less than non-pregnant mares (P = 0.030), young horses (age 0-5 years) sniffed cedar wood for longer than old horses (P = 0.030), whereas sex had no effect (P > 0.050). The results show that horses’ odor exploration behavior and interest in odors varies with age and pregnancy and that horses naïve to the taste of a substrate, may be able to link smell with taste, which has not been described before. These results can aid our understanding of horses’ behavioral reactions to odors, and in the future, it may be possible to relate these to the physiology and health of horses

Rider effects on horses’ conflict behaviour, rein tension, physiological measures and rideability scores

Many breeding organisations include a subjective scoring of rideability by a professional rider into their evaluation of sports horses, but the consistency and reliability of the scoring system is debateable. The aim of this study was to investigate (i) whether professional riders agree in their scoring of rideability, and (ii) whether rideability scores are affected by rein tension, horse conflict behaviour, heart rate, and salivary cortisol, and (iii) whether riders induce different levels of conflict behaviour and physiological responses in the horses. Ten professional, female riders each rode 10 dressage horses (level M German scale; n = 100 combinations) through a standardised dressage test (10 min warm-up followed by a 4-min test) and subsequently scored the horses for rideability on the official 1–10 scale (1 = poor to 10 = excellent) from the Danish Riding Federation. Rein tension, horse heart rate, saliva cortisol and conflict behaviour were measured for each rider-horse pair. The riders were inconsistent in their scoring of rideability to the individual horses, e.g. scores for one of the horses ranged from 1 to 8. There was a significant effect of rider (P = 0.003) and the frequency of conflict behaviour (undesired head movements: P < 0.001, breaking the gait: P = 0.013, and other evasive behaviour: P = 0.032) on rideability scores, i.e. the more conflict behaviour the lower the score. There was no significant effect of rein tension and the physiological measures on rideability scores. However, there was a significant effect of rider on rein tension, horses’ heart rate and increases in saliva cortisol concentrations and a tendency for some types of conflict behaviour, suggesting that some riders induced more discomfort in the horses. Future studies could help shed light on which elements of riding style are particularly important for sports horse welfare. In conclusion, this study found a large variation in rideability scores assigned to ten sports horses by ten professional riders. Rideability scores were dependent on the level of horse conflict behaviour, but not rein tension and physiological measures. Further studies are needed to improve the objectivity, consistency and reliability of rideability assessment of sports horses

Odor exploration behavior of the domestic pig (Sus scrofa) as indicator of enriching properties of odors

Introduction and aim: Although the sense of smell in pigs is widely recognized as being highly developed, surprisingly little is known about their sensory ability. This study aimed to (a) identify which non-social odors pigs were able to detect and distinguish between, (b) investigate the types of behavior expressed when exploring odors and, (c) compare pigs’ responses to the different odors to evaluate their interest in the odors.Methods: Growing pigs (N = 192) of crossbred commercial breeds were enrolled in the experiment (32–110 days of age, weighing 64.9 ± 10.1kg). Littermate pairs of opposite sex were tested in test pens with two odor insertion points in the pen wall, 55 cm apart. All pigs were habituated to the test pens and experimenters. Twelve odors were tested (eight essential oils and four synthetic perfumes) in groups of three odors, with each pig pair tested once with one set of three odors (all possible orders of the three odors were tested on 24 pairs in total), always against a non-odor control (demineralized water). In a test, each of the three odors were presented during three trials in a row (a total of 9 trials per test; trial duration: 1 min; inter-trial breaks: 2 min; total test duration: 25 min). Response variables included: duration of sniffing, feeding-related behavior (licking, biting and rooting), agonistic behavior (biting, displacement and pushing) and no approach of the odor or control, recorded throughout each 1-min odor presentation.Results: All pigs sniffed an odor less when repeatedly presented (LMM: all odors P Conclusion: Collectively, pigs express sniffing, agonistic, and feeding-related behavior when exploring odors, which suggests that pigs perceive odors of non-social origin as a resource. Odors may thus constitute relevant enrichment material for pigs

Grisars doftundersökningsbeteende - data från del 1 av projekt "Lukta på det här"

These studies are connected to the first part in a larger project called "Smell This". Study 1 aimed to a) identify which non-social odors pigs were able to detect and distinguish between, b) investigate the types of behavior expressed when exploring odors and, c) compare pigs’ responses to the different odors to evaluate their interest in the odors. Growing pigs (N=192) of crossbred commercial breeds were enrolled in the experiment . Littermate pairs of opposite sex were tested in test pens with two odor insertion points in the pen wall. Twelve odors were tested (8 essential oils and 4 synthetic perfumes) in groups of three odors, with each pig pair tested once with one set of three odors (all possible orders of the three odors were tested on 24 pairs in total), always against a non-odor control (demineralized water). In a test, each of the three odors were presented during 3 trials in a row (a total of 9 trials per test; trial duration: 1 min; inter-trial breaks: 2 min; total test duration: 25 min). Response variables included: duration of sniffing, feeding-related behavior (licking, biting and rooting), agonistic behavior (biting, displacement and pushing) and no approach of the odor or control, recorded throughout each 1-min odor presentation. Study 2 describes two behaviours unexpectedly observed in a study assessing pigs’ reactions to odours and not previously reported in pigs. The study included the same 192 pigs of commercial breeds as study 1, tested with 12 different odours of non-social origin: 8 essential oils and 4 synthetic perfumes, plus an odourless control. The study found that, when exposed to odours, pigs display rubbing and rolling behaviour. Overall, essential oils (lavender, thyme, blood orange, aniseed, cedarwood, cinnamon bark, ginger, and pine) elicited more of the behaviours than the synthetic perfumes (vanilla, musk, apple, and jasmine) or the odourless control. All odours elicited rubbing whereas only four odours (blood orange, ginger, lavender, and pine) elicited rolling. This is the first report of rubbing and rolling as a response to an odour in pigs. The experiment connected to the project were video recorded, and behavioral data was later extrated from the digital videos. All behavior was recorded separately for both the odor and the control points, separately, by an experienced observer blind to the specific odor tested. Study 1 - During each odor presentation, the total sniffing behavior of each pig (i.e., sniffing duration summed for the pig pair per odor presentation) was recorded using continuous sampling of each 1-min odor presentation. Habituation was defined as a significant decrease in sniffing of the odor between at least two of the three presentations of the same odor, and dishabituation was defined as a reinstatement of sniffing (significant increase in sniffing duration) when a new odor sample is presented. Feeding-related behavior and agonistic behavior as well as no approach were continuously recorded using behavior sampling. Feeding-related behavior was recorded as a collective duration for both pigs during each odor presentation (as for sniffing). Agonistic behavior was also collectively recorded for both pigs during each presentation as duration per odor presentation. The data connected to Study 1 is comprised of three excel files. 1) The full data "Study 1_Data_full" contains all variables described above, split by odor vs control. Study 1_Data_full contains 20 columns, and 829 rows. Each row represents one pig pair (i.e., 2 pigs), hence this data is at pair level. Specific odor and odor type (essential oil (=E)or synthetic perfume (=P)) is given. Odour sequence refers to the different sequences of the three odors tested A-Y. Trial represents the odor presentation: 1st, 2nd, and 3rd. All behaviours are measured in seconds, a part from the "No approach" column which is a 1/0 variable = no approach or not. 2) The "Study 1_Dishabituation" data sheet contains data used to investigate dishabituation. The data sheet contains 8 columns and 369 rows. The response variable "Sniff" is the same as in Data_full but data is arranged differently in order to investigate 3rd vs 1st presentations. Odor and odor type is given as in Study 1_Data_full, and odor comparison is given. Trial refers to the presentation as in Study 1_Data_full, with only the 3rd and 1st presentations included. Comparison number a or b refers to which of the two comparisons within each pig pair, a being the first transition from the 3rd presentation of the first odor to the 1st presentation of the new (second) odor, whereas b refers to the 3rd presentation of the second odor, compared with the subsequent 1st presentation of the new odour (third). The order column illustrates the order of each variable. 3) Study 1_Data_sniffing_overtime contains the variable sniffing of the odor, but with odors anonymised, and only odor number represented: odor 1, 2 and 3. The data sheet contains 6 columns, and 829 rows. Study 2 - During each odor presentation, the total duration and frequency of rubbing and rolling behaviour as well as number of rolling attempts of each pig (i.e., all parameters on pair and individual level) were recorded using behaviour sampling of each 1-min odor presentation. The data connected to Study 2 is comprised of two excel files. 1) The full data "Study 2_Data_full_RubRoll" contains all variables described above, split by odor vs control. This data contains 10 columns, and 829 rows. Each row represents one pig pair (i.e., sum of 2 pigs), hence this data is at pair level (pig pair is given in the first column). Specific odour and odour type (essential oil (=E)or synthetic perfume (=P)) is given. Presentation refers to the presentation number within one odour i.e., 1st, 2nd or 3rd presentation of the same odour. Order refers to which odour in the order of total three odours presented i.e., odour 1, odour 2, or odour 3. All behaviour durations are measured in seconds, and frequencies are measures as total occurrence for the pig pair, per presentation. 2) The "Study 2_Individual_data_RubRoll" data sheet contains data used to investigate the behaviours at individual level. The data sheet contains 14 columns and 140 rows. This number of rows are lower due to exclusion of the many individuals not expressing the focus behaviours (rubbing or rolling or rolling attempt). Odour and odour type is given as in Study 2_Data_full_RubRoll, and odour number refers to which odour out the total three (1, 2 or 3). Presentation refers to the same as for Study 2_Data_full_RubRoll, the presentation number within one odour i.e., 1st, 2nd or 3rd presentation of the same odour. Age of the pig given in days, and breed (cross breeds), and sex (female or male) is further given.Denna studie är en del av ett större projekt som innehåller flera olika försök/studier. Denna specifika studies syfte var att undersöka vilka dofter grisar kunde upptäcka och skilja på, samt vilka typer av beteende grisar visar när de utforskar olika dofter. En mer detaljerade beskrivning finns på den engelska sidan. Försöken videoöverkades och beteenden blev sedan observerade via videofilmerna. Datan innehåller observerad beteenden för både doft- och kontrollpunkter (dvs. dofter och doftlösa). En mer detaljerad beskrivning finns på den engelska sidan

An added aroma changes the behaviour of domestic pigs in a novel situation aimed for stunning

The currently most widespread stunning method for pigs is high concentration of carbon dioxide (CO2), but this method is under scrutiny due to animal welfare deficits. One alternative method currently under development with potential to replace CO2 is nitrogen (N2) filled high expansion foam. While N2 does not elicit the same aversive behaviour as CO2, it is currently not known if the high expansion foam itself may be frightening to the pigs. Means to alleviate fear reactions to foam could consist of diverting pigs' attention using aromas (an odour in combination with taste) of interest to them. The current study aimed to investigate if an added aroma (vanilla aroma) affected pigs' avoidance and exploratory behaviour when exposed to air-filled high expansion foam in a foam box. The study included 50 pigs (30 females, 20 males) of 14-16 weeks of age, of different crosses between Yorkshire, Hampshire and Duroc. The pigs were randomly assigned to either the treatment with air-filled foam with added aroma or the control treatment with no added aroma, which they were exposed to in a foam box. The results showed that pigs with the aromatised foam expressed significantly more exploration behaviour directed towards the foam and box walls, but not towards the floor or the lid. The aromatised foam also resulted in a higher activity level of the pigs. In contrast to the hypotheses, pigs with aromatised foam expressed more avoidance behaviour, and escape attempts were exclusively observed when pigs were exposed to aromatised foam. Slipping events and frequency of vocalisations did not differ between pigs with and without aroma added to the foam. This study shows that an added aroma (taste and odour in combination) increased pigs' exploration behaviour towards the foam, and thus could serve as a distraction for the pigs when inside a confined foam box. The results emphasise the importance of taking foam aroma into consideration in the further development of the N2-filled high expansion as a stunning method. The potential anxiety- or stress-reducing effect of any added aroma needs further investigation, and future studies should focus on assessing various types of aromas, and/or odours, as well as different concentrations of the compounds to determine which solution is most efficient in alleviating pig stress and anxiety