Chemical communication in wild Norway rats: (Rattus norvegicus Berkenhout)

This study examined the urine and faecal scent marking behaviour and investigatory responses of wild Norway rats (Rattus norvegicus Berkenhout) kept in large, semi-natural enclosures to assess the role these scents play in their communication system. For the first time, this study has shown that Norway rats deposit faecal scent marks in response to odour cues and form latrines. The spatial distribution of faeces was highly uneven. Most faeces deposited in open areas were found in clusters occupying less than 1 m2 which were termed latrines. Rats spent more time at feeders and in other areas which were almost devoid of faeces than at these latrines. This suggests that latrines were created deliberately, perhaps for communication. Rats discriminated among faeces from different donors with respect to their investigation, presumably using olfactory cues. They faecal marked in response to urine cues from rats belonging to other colonies, although they did not faecal mark in response to their own urine cues or to a novel non-social stimulus (clean tiles). Investigation and faecal marking was aimed mainly towards urine from individuals of the marker's own sex. This suggests that faecal marking may play a role in communication between competitors. Urine was deposited as discrete marks around the enclosures, in an uneven distribution. The highest density of marks was found by the enclosure walls and nest areas. Rats showed a greater urine marking response towards introduced clean surfaces than towards surfaces they had already marked, ensuring that their home area was always covered with their urine marks. Close monitoring of urine marking on clean surfaces showed that male -rats had a marking rate three times greater than that of females. This could not be attributed solely to weight differences between males and females. Rats also urine marked in response to urine deposited by rats from other colonies. Urine from unfamiliar rats of the subject's own sex stimulated more investigation than urine from the opposite sex, though donors were immature. These results suggest that urine marking also plays a role in communication between competitors. Testing individuals in their home enclosure, using scent marks deposited naturally by rats, and the contexts in which scent stimuli are deposited by donors (e. g. as part of their home range) and found by residents (e. g. finding intruder's home range marks in the resident's home range) were essential factors in determining their response to olfactory cues. The importance of these factors is discussed

Chemical communication in wild Norway rats: (Rattus norvegicus Berkenhout)

This study examined the urine and faecal scent marking behaviour and investigatory responses of wild Norway rats (Rattus norvegicus Berkenhout) kept in large, semi-natural enclosures to assess the role these scents play in their communication system. For the first time, this study has shown that Norway rats deposit faecal scent marks in response to odour cues and form latrines. The spatial distribution of faeces was highly uneven. Most faeces deposited in open areas were found in clusters occupying less than 1 m2 which were termed latrines. Rats spent more time at feeders and in other areas which were almost devoid of faeces than at these latrines. This suggests that latrines were created deliberately, perhaps for communication. Rats discriminated among faeces from different donors with respect to their investigation, presumably using olfactory cues. They faecal marked in response to urine cues from rats belonging to other colonies, although they did not faecal mark in response to their own urine cues or to a novel non-social stimulus (clean tiles). Investigation and faecal marking was aimed mainly towards urine from individuals of the marker's own sex. This suggests that faecal marking may play a role in communication between competitors. Urine was deposited as discrete marks around the enclosures, in an uneven distribution. The highest density of marks was found by the enclosure walls and nest areas. Rats showed a greater urine marking response towards introduced clean surfaces than towards surfaces they had already marked, ensuring that their home area was always covered with their urine marks. Close monitoring of urine marking on clean surfaces showed that male -rats had a marking rate three times greater than that of females. This could not be attributed solely to weight differences between males and females. Rats also urine marked in response to urine deposited by rats from other colonies. Urine from unfamiliar rats of the subject's own sex stimulated more investigation than urine from the opposite sex, though donors were immature. These results suggest that urine marking also plays a role in communication between competitors. Testing individuals in their home enclosure, using scent marks deposited naturally by rats, and the contexts in which scent stimuli are deposited by donors (e. g. as part of their home range) and found by residents (e. g. finding intruder's home range marks in the resident's home range) were essential factors in determining their response to olfactory cues. The importance of these factors is discussed

Nota corta. Aplicación de la ultrasonografía transrectal en el diagnóstico precoz de gestación y evaluación de la mortalidad embrionaria/fetal en ciervas ibéricas mantenidas en granja

[EN]: The main objective of the present study was to evaluate the accuracy of the trans-rectal ultrasonography technique applied to the Iberian red deer hinds since it has not been previously documented in Spain. Experimentation was also used to test the hypothesis that a lower fertility in young hinds could be due to an increment in embryonic or foetal mortality. For this purpose, 116 hinds divided in three groups depending on its age (young, adults and senescent) were examined by rectal ultrasonography and the different foetal structures measured two months after the males were removed from the groups of hinds. With these data, specificity and predictive value of negative diagnoses of the technique has been calculated. Trans-rectal ultrasonography is an accurate technique to use in Iberian red deer dams with overall levels of pregnant detection near to 92%. Finally, the youngest hinds showed poorer fertility rates (17.24% vs. 59.30% and 58.33% of senescent and prime-age respectively) and also higher of embryonic or foetal mortality (2 deaths out of 7 positive pregnant diagnoses compared with no deaths in the senescent group and 4 deaths out of 39 positive pregnant diagnoses in the prime-age group).[ES]: El objetivo principal del presente estudio ha sido evaluar la precisión de la ultrasonografía transrectal aplicada a las ciervas ibéricas, ya que no ha sido documentado previamente en España. Paralelamente, se ha intentado comprobar la hipótesis de que la menor fertilidad en las hembras más jóvenes podría deberse a una mayor mortalidad embrionariofetal. Para ello, 116 hembras divididas en tres grupos en función de su edad (jóvenes, adultas y viejas) fueron ecografiadas a los 2 meses de la retirada de los machos y medidas las diferentes estructuras fetales. Con estos datos se ha calculado la especificidad y seguridad en el diagnóstico negativo de la técnica. La ultrasonografía transrectal es una técnica precisa para su uso en ciervas ibéricas, con niveles de detección de gestación cercanos al 92%. Finalmente, las ciervas más jóvenes muestran peores índices de fertilidad (17,24% vs 59,30% y 58,33% del grupo de viejas y adultas respectivamente) y mayores mortalidades embrionario-fetales (2 muertes de 7 diagnósticos gestantes positivos en comparación con ninguna muerte en el grupo de hembras de más edad y con 4 muertes de 39 diagnósticos gestantes en las hembras adultas).Peer Reviewe

Can Iberian red deer (Cervus elaphus hispanicus) discriminate among essential minerals in their diet?

Optimal foraging predicts that animals should be able to assess the content of important nutrients in food. Ungulates discriminate salt and P, but discrimination of other minerals is controversial even though they are also essential and often limiting. Animal scientists have explained this taste through palatability, which predicts the same pattern of discrimination for calves and hinds and greater consumption by the latter. Social learning may also be involved, predicting a correlation between mother and calf and less consumption by the latter. The present study examines the consumption behaviour of free-choice supplemented minerals by hinds and calves of Iberian red deer (Cervus elaphus hispanicus) to discern between these hypotheses. Behavioural indices of intake correlated with actual mineral consumption (P,0·001). Mother and calf behavioural indices correlated only for salt-mixed minerals. Calves showed overall behavioural indices of consumption greater than hinds (P,0·01 and P,0·001), and also for all single supplements except NaCl, as expected from growth needs and in contrast to the palatability hypothesis. Calves showed a greater consumption of CuSO4 and lower of Na2SeO3 than pure salt. Hinds showed a different pattern, ingesting lower amounts of all minerals except CuSO4 and salt. Additional analyses also showed discrimination between minerals unmixed with salt, such as CaHPO4 and CaCO3 (P¼0·012 and P¼0·020). The greater intake of growing calves and the different consumption patterns for hinds and calves suggest that deer can discriminate among minerals, and that they do not consume minerals for their palatability or driven by social learning. Therefore, deer may be selecting minerals according to nutritional requirements.The present study was supported by projects CGL2008-00749/BOS (Ministerio de Ciencia e Innovacion-Fondo Europeo de Desarrollo Regional) and PC108-0115 (Junta de Comunidades de Castilla-La Mancha).Peer Reviewe

Habituating to handling: Factors affecting preorbital gland opening in red deer calves

The preorbital gland plays not only an olfactory role in cervids but also a visual one. Opening this gland is an easy way for the calf to communicate with the mother, indicating hunger/satiety, stress, pain, fear, or excitement. This information can be also useful for farm operators to assess how fast the calves habituate to handling routines and to detect those calves that do not habituate and may suffer chronic stress in the future. Thirty-one calves were subjected to 2 consecutive experiments to clarify if observing preorbital gland opening is related to habituation to handling in red deer calves (Cervus elaphus). Calves were born in 3 different paddocks, handled as newborns (Exp. 1), and then subjected to the same routine handling but with different periodicity: every 1, 2, or 3 wk (Exp. 2). In Exp. 1, preorbital gland opening was recorded in newborns during an initial handling (including weighing, ear tagging, and sex determination). Preorbital gland opening occurred in 93% of calves during this procedure and was not affected by sex, time since birth, or birth weight. Experiment 2 consisted of measuring preorbital opening during the same routine handling (weighing, blood sampling, and rump touching to assess body condition) when calves were 1, 3, and 5 mo old. Binary logistic regression showed that gland opening was associated with habituation to handling, since at 1 and 3 mo the probability of opening the gland decreased with the number of handlings that a calf experienced before (P = 0.008 and P = 0.028, respectively). However, there were no further changes in preorbital gland opening rate in the 5-mo-old calves (P = 0.182). The significant influence of the number of previous handlings on the probability of opening the preorbital gland was confirmed through generalized linear model with repeated measures (P = 0.007). Preorbital gland opening decreased along the phases of the study. Nevertheless, we found a significant trend in individuals to keep similar opening patterns (intraclass correlation coefficient = 0.807, P < 0.001), which suggests that the more stressed individuals can be detected with this method. Therefore, we conclude that preorbital gland opening during routine handlings is related to the number of previous handlings, and thus it can be used as an indicator of lack of habituation to handling in farmed cervids.This study was supported by projects AGL2012-38898 (Ministry of Economy and Competitiveness, Spain), MZERO0714‏ (Ministry of Agriculture, Czech Republic), CIGA20145001 (Czech University of Life Sciences, Czech Republic), and IGA no. 20145026 (Faculty of Tropical AgriSciences, Czech Republic).Peer Reviewe

Plasmatic protein values in captive adult Iberian red deer stags (Cervus elaphus hispanicus)

The aim of this study was to assess the time trend of plasmatic proteins in red deer stags. Blood samples were taken monthly from 17 male red deer for 22 months. Total plasmatic determination and protein electrophoresis were performed. Plasmatic proteins showed minimum values during spring and summer and a maximum at the peak of the mating period. Total globulins, β and γ, followed a pattern similar to that observed for total proteins, whereas α1 and α2 globulins showed no seasonal variations. Albumin showed higher values in early spring and summer and lower values at the beginning of autumn, coinciding with the mating season. These seasonal changes in plasmatic proteins should be taken into account when assessing blood protein analysis results.This study was funded by projects AGL2007-63838/gan, PBI-05-040, PAC 06-01304298 and PET2006-0263 and MICINN (PTQ 09-02-01923).Peer Reviewe

The power of oral and nasal calls to discriminate individual mothers and offspring in red deer, Cervus elaphus

[Background]: In most species, acoustical cues are crucial for mother-offspring recognition. Studies of a few species of ungulates showed that potential for individual recognition may differ between nasal and oral contact calls. [Results]: Vocalizations of 28 hinds and 31 calves of farmed Iberian red deer (Cervus elaphus hispanicus) were examined with discriminant function analyses (DFA) to determine whether acoustic structure of their oral and nasal contact calls encodes information about the caller's identity. Contact calls were elicited by brief separation of individually identified animals by a distance over 10 m or by a bar fence. Both oral and nasal calls of both hinds and calves showed high potential to discriminate individuals. In hinds, individuality was significantly higher in the oral than in the nasal calls, whereas in calves, individuality was equally well expressed in both oral and nasal calls. For calves, the maximum fundamental frequency was higher and the duration was longer in oral calls than in nasal calls. For hinds, the maximum fundamental frequency and the duration were indistinguishable between oral and nasal calls. Compared to the pooled sample of oral and nasal calls, separate oral or nasal call samples provided better classifying accuracy to individual in either hinds or calves. Nevertheless, in both hinds and calves, even in the pooled sample of oral and nasal calls, the degree of individual identity was 2-3 times greater than expected by chance. For hinds that provided calls in both years, cross-validation of calls collected in 2012 with discriminant functions created with calls from 2011 showed a strong decrease of classifying accuracy to individual. [Conclusions]: These results suggest different potentials of nasal and oral calls to allow the discrimination of individuals among hinds, but not among red deer calves. The high potential of individual recognition even with the pooled sample of oral and nasal calls allows mother and young to remember only one set of acoustic variables for mutual vocal recognition. Poor between-year stability of individual characteristics of hind oral and nasal calls would require updating keys to individual recognition each calving season.This study was supported by the Russian Scientific Foundation, grant No 14-14-00237 (for IV, EV, OS and VM) and by Ministerio de Economía y Competitividad, Spain, project AGL2012-38898 (for TL, AG and LG).Peer Reviewe

Manganese supplementation in deer under balanced diet increases impact energy and contents in minerals of antler bone tissue

Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings) red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10) that were divided in a manganese injected group (n = 14) and a control group (n = 15). Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler) showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced), and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.Funding was provided by Ministerio de Economía y Competitividad, Government of Spain (MINECO): Project AGL2012-38898 to TLC, AG, LG, FC, JC; Consejería de Educación y Deportes de Castilla-La Mancha: Project PEII-2014-004-P to LG TLC AG.Peer Reviewe

The Many Axes of Deer Lactation

In undomesticated animals information about the production and composition of milk over time is still scarce. In general, for most mammals it is known that milk composition changes across lactation, is different for male and female offspring, and even that marsupials, such as kangaroos, can simultaneously produce milk of different compositions for young of different ages. Such parallel milk production of differing compositions has not yet been studied in single-offspring placental mammals, but may help to explain behavioural processes like allosuckling (feeding the young of other adults) and lateralized suckling preferences. In this study we analysed the production and composition of milk in red deer throughout the lactation period and now confirm for the first time that there are axial differences present. The front teats, which are the favoured suckling positions of the deer?s offspring, produce milk with a greater protein-to-fat ratio. Also, from the beginning of lactation the yield is greater on the left side, the side preferred by calves in all of the studied species, both at population and individual level. The links between milk production and calf behaviour in deer deserve further stud

Morphology, chemical composition, mechanical properties and structure in antler of Sardinian red deer (Cervus elaphus corsicanus)

The deer population present in Sardinia and Corsica represents an endemic subspecies Cervus elaphus corsicanus. We describe for the first time the characteristics of cast antlers of Sardinian red deer from the forest complex Sette Fratelli, south-east part of the island. Moreover, we describe the material mechanical properties, the structural ones, and the mineral profile of antlers from adults, comparing them with the antler characteristics of the subspecies C. e. hispanicus examined exactly with the same methodology. Sixty-one deer casted antlers were collected and classified as belonging to adults (35) or sub-adults (26). A first part of the study described the common features of the antlers of sub-species C. e. corsicanus through the analysis of morphology in all deer antlers. Subsequently, a more detailed study used 12 adult deer antlers for a destructive analysis. Statistical comparisons were conducted using ANOVAs between characteristics of the two age subgroups, and using Pearson´s correlation coefficients between the antlers morphological variables. In general, morphological antler measures had greater values in adults than in sub-adults. In comparison with Iberian deer, Sardinian adult antlers have a more simple structure with lower values in morphological features, mechanical properties and structural characteristics