Abstract: The complex housing environment and the close contact between humans and horses in equine sports place high demands on the learning capacity of horses. To date only limited information is available on the learning ability of the horse including higher order cognition. A type of higher order cognition is to perceive and discriminate quantities. Several mammals and birds have shown to be capable of discriminating objects due to their quantity (Brannon and Roitman, 2003). With regard to horses, there are only few studies available concerning their numerosity judgment (Uller and Lewis, 2009) and this ability is discussed controversially (Henselek et al, 2012). Possibly, the legacy of ‘‘Clever Hans’’ overshadowed further research on numerical capacity in horses, a horse to whom several psychologists incorrectly attributed the capacity of symbolic calculation (Pfungst, 1907; Rosenthal, 1965). In the present study we wanted to show whether Shetland ponies are able to transfer a previously learned concept of sameness to a numerosity judgment. The base of the test design was a “matching to sample” task, where the ponies had learned to relate abstract symbols to another which were presented on a LCD screen. Three Shetland ponies, which previously solved the matching to sample task, were tested in two test phases. In the first test phase different quantities of dots were presented (1 vs. 2; 2 vs. 3; 3 vs. 4; 4 vs. 5). To exclude discrimination due to the shape of the stimuli, the dots were varied in size and arrangement. The stimuli were presented in a triangular arrangement on the LCD screen; the sample stimulus was presented in the middle above and the discrimination stimuli in the two lower corners (S+ and S-). The pony received a food reward, by choosing the positive stimulus (S+). When the negative stimulus (S-) was chosen, the pony entered the next trial. Each learning session consisted of 20 decision trials. To investigate whether the numerosity judgment was transferable to mixed geometrical symbols (tri-, rectangle, rhomb, dot and cross) a second test phase was designed. All of the three Shetland ponies met the learning criterion of the first test phase (80% correct responses in two consecutive sessions) within the first eight sessions. One pony could transfer all judgments to the mixed symbols (up to 4 vs. 5), another pony up to 3 vs. 5 and the third on the level 2 vs. 3. These are the first reported findings that ponies are able to discriminate up to five objects. The numerosity judgment seemed to be easier for the ponies when homogenous objects were presented, than in the case of heterogeneous symbols. The reaction of the ponies occurred within few seconds, suggesting that the animals used subitizing for their numerosity judgment.
Keywords:
Cognition, numerical capacity, numerosity judgment, Shetland ponys
References:
Brannon E, Roitman J (2003) Nonverbal representations of time and number in animals and human infants. In: Meck WH (ed) Functional and neural mechanisms of interval timing. CRC Press, Boca Raton, pp 143–182
Henselek Y, Fischer J, Schloegl C (2012) Does the stimulus type influence horses’ performance in a quantity discrimination task? Front Psychol 3:504
Pfungst O (1907) Der Kluge Hans. Ein Beitrag zur nicht-verbalen Kommunikation. 3rd edn. (reprint of the original 1983) Frankfurter Fachbuchhandlung für Psychologie, Frankfurt
Rosenthal R (1965) Clever Hans: the horse of Mr. Von Osten. Holt, Rinehart and Winston, New York
Uller C, Lewis J (2009) Horses (Equus caballus) select the greater of two quantities in small numerical sets. Anim Cogn 12:733–738

Abstract: The responsiveness of 10 horses and 10 ponies to environmental challenge (represented by an open field test) was assessed using a qualitative approach based on free choice profiling methodology (FCP), which gives observers complete freedom to choose their own descriptive terms. Data were analysed with generalised Procrustes analysis (GPA), a multivariate statistical technique associated with FCP. A cross-validation of the outcomes of this approach to data recorded through quantitative behaviour analysis, and through a questionnaire given to the animals' owner/riding instructor, was also performed using principal component analysis (PCA). Twelve undergraduate students generated their own descriptive vocabularies, by watching 20 horse/pony video clips lasting 2.5 min each. GPA showed that the consensus profile explained a high percentage of variation among the 12 observers, and differed significantly from the mean randomised profile (p < 0.001). Two main dimensions of the consensus profile were identified, explaining 60% and 5.2% of the variation between animals, respectively. The 12 observer word charts interpreting these dimensions were semantically consistent, as they all converged towards the same meaning, albeit using different terms. The most used term to describe the positive end of axis 1 was “quiet”, whereas “attentive” was the best positive descriptor of axis 2. The most frequently used descriptors for the negative ends of axes 1 and 2 were “nervous” and “bored”, respectively. Thus, axis 1 was labelled as “quiet/nervous” and axis 2 was named as “attentive/bored”. A marked effect of animal category was observed on the scores of the animals on the first dimension (p < 0.001). Horses received significantly higher scores, and were thus assessed as more quiet and calm, than ponies. Conversely, ponies tended to receive lower scores on the second dimension (p < 0.12), therefore they appeared less curious and attentive. The results of the PCA showed that the variables from different types of measurement clearly had meaningful relationships. For instance, the variables with the highest loading on the positive end of axis 1 were all indicative of tractable and docile animals, whereas axis 2 showed high loadings on the positive end for variables indicating attentive animals. Qualitative behaviour assessment proved to be an appropriate methodology for the study of horse behavioural responsiveness, in that it provided a multifaceted characterisation of horse behavioural expression that was in agreement with other quantitative and subjective assessments of the animals' behaviour.

Abstract: The aim of this comparative study was to gain more information about the excretion of steroid hormones in farm animals. This should help to establish or improve non-invasive steroid monitoring procedures, especially in zoo and wildlife animals. Over a period of 4 h the 14C-steroid hormones (3.7 MBq) progesterone (three females), testosterone (three males), cortisol and oestrone (two males, two females) were infused intravenously in sheep, ponies and pigs. Faeces were collected immediately after defecation. Urine was sampled via a permanent catheter in females and after spontaneous urination in males. A total of 88 +/- 10% (mean +/- SD) of the administered radioactivity was recovered. Considerable interspecies differences were measured both in the amounts of steroid metabolites excreted via faeces or urine and the time course of excretion. Progesterone and oestrone in ewes, and progesterone in mares were excreted mainly in the faeces (over 75%). The primary route of excretion of all other 14C-steroids was via the urine but to a different extent. In general, sheep showed the highest degree of faecal excretion and pigs the least. The highest radioactivity in urine (per mmol creatinine) was observed during the infusion or in one of the next two samples thereafter, whereas in faeces it was measured about 12 h (sheep), 24 h (ponies) or 48 h (pigs) after the end of the infusion. Thereafter the radioactivity declined and reached background levels within 2-3 weeks. In faeces, steroid metabolites were present mainly in an unconjugated form, but in blood and urine as conjugates. Mean retention time of faecal radioactivity suggested that the passage rate of digesta (duodenum to rectum) played an important role in the time course of the excretion of steroids. The information derived from this investigation could improve the precision of sampling as well as the extraction of steroids from the faeces. Furthermore, the study demonstrates that it should be possible to establish methods for measuring faecal androgen and cortisol metabolites for assessing male reproductive endocrinology and stress in animals.