23 Mare-foal interactions in Peruvian horses and in Peruvian foals raised by surrogate regional mares Monique Halloy1, 3, Sara Jerez2, 3, Cecilia Robles1, 2, 3, Ileana Nicolari2, 3, Luciana Marangoni 2, 3, Fabricia Guglielmone 1, 2, 3, & Fernando Escalante3 Fundación Miguel Lillo, Miguel Lillo 251, 4000 San Miguel de Tucumán, Argentina; e-mail: email@example.com Facultad de Ciencias Naturales, Universidad Nacional de Tucumán, Miguel Lillo 205, 4000 San Miguel de Tucumán, Argentina 3 Fundación Hippus, Santa Fe 1385, 4000 San Miguel de Tucumán, Argentina; e-mail: firstname.lastname@example.org 1 2 Received: 14 October 2003; initial acceptance: 17 March 2004; accepted: 28 June 2004.
Published on-line: 7 July 2004.
We studied mare-foal interactions in two groups of horses to investigate possible differences between them with respect to separation of the foals.
One group consisted of Peruvian mares and their foals and another of regional mares used as surrogate mothers to Peruvian foals that had been implanted as embryos.
We considered two factors: the distance at which mother and foal remained from one another (within a 5m radius or beyond) and the time the foal spent nursing.
Data were obtained from birth to nine months for the first group and from birth to nine weeks for the second group.
Pairs from the first group were filmed once a week during the first 12 weeks and once every month thereof .
In both groups we observed that the distance between foals and their mothers increased and that nursing decreased over time.comparison of the two groups showed no statistically significant differences in these two parameters during the first nine weeks.
At almost nine months of age, Peruvian foals still remained within a 5m radius of their biological mothers for nearly two-thirds of their time, indicating a long term bond between mothers and their young.
Keywords: Horses; Mare-foal interactions; Peruvian breed; Surrogate mothers Resumen.
Interacciones entre yeguas y potrillos de caballos peruanos y en potrillos peruanos criados por yeguas regionales sustitutas.
Estudiamos interacciones en yeguas y potrillos de dos grupos de caballos para investigar posibles diferencias entre ellos con respecto a la separación de los potrillos.
Un grupo consistía en yeguas peruanas y sus potrillos y otro en yeguas regionales usadas como madres sustitutas para potrillos peruanos que habían sido implantados como embriones.
Consideramos dos factores: la distancia a la que se mantenían la madre y el potrillo el uno del otro (dentro de un radio de 5m o más allá) y el tiempo que el potrillo pasaba mamando, desde el nacimiento hasta los nueve meses para el primer grupo y desde el nacimiento hasta nueve semanas para el segundo grupo.
Madres y crías fueron filmados una vez por semana durante las primeras 12 semanas y una vez cada mes despues de eso.
Encontramos que, en ambos grupos, la distancia entre potrillos y sus madres aumentaba y que el amamantamiento disminuía con el tiempo.comparamos los dos grupos estadísticamente y no hubo diferencias significativas en estos dos parametros, durante las primeras nueve semanas.
Encontramos que los potrillos Peruanos seguían quedando dentro de un radio de 5m de sus madres biológicas casi los dos tercios de su tiempo al alcanzar los nueve meses de edad, indicando un vínculo a largo plazo entre la madre y su cría. Introduction Although several studies have reported on motheryoung interactions in different breeds of horses, Equus caballus (eg, Duncan et al., 1984; Crowell-Davis, 1985; Estep et al., 1993), to our knowledge this is the first study to date on the Peruvian breed and a unique case of Peruvian foals raised by surrogate regional mothers implanted with the embryos.
The surrogate mares were not first time mothers and they were chosen based on their favorable behavior towards previous foals and on © 2003 Sociedad Española de Etología good lactation.
According to De Ascásubi (1968), the Peruvian breed originated from 3 different breeds, Spanish, Frisona and Berberisco, while Ferrer (1999) proposed that it originated from the Andalusian and Berberisco breeds.
The Peruvian breed is mostly known for its special lateral gait, in contrast with the typical transverse gait of most other horses and quadrupeds.
We compare Peruvian foals raised by their biological mothers with Peruvian foals raised by surrogate mothers of another breed with respect to separating from 24 Halloy et al: mare-foal interactions in horses their mothers.
We considered the distances maintained between mothers and their young and also the time the foals spent nursing over a determined period of time. Materials and methods Animals and locations Two different groups of horses were studied.
They were observed in relatively large fields where they spent most of their time during the day and night, the mares grazing on local grasses, or resting under an occasional tree, the foals nursing, sometimes trying and eating the different grasses (McDonnell and Poulin, 2002), resting, or frolicking close to their mothers.
One group consisted of Peruvian mares and their foals (location “El Algarrobo”, province of Tucumán, Argentina; size 80 hectares).
Although there were more than 20 pairs of mothers and foals of different ages in this group, they were not always available for filming (eg, veterinarian’s visit, in preparation for shows or exhibits).
Other mares without foals, yearlings and geldings were also present.
The actual number of pairs that were filmed and the average time filmed per pair at different age-periods of the foals’ lives are given in Table 1.
The second group consisted of surrogate regional mothers and their Peruvian foals (location “Los Copiangos”, province of La Rioja, Argentina; size 40 hectares).
There were 12 pairs of mothers and foals in this second group.
No other horses were present.
On many weeks, only 4 pairs or fewer were available for filming.
Because of this, and because of the travel distance to the site (about 5hrs), we did not obtain as much data as for the first group.
Number of pairs filmed and the average time each pair was filmed per age category are shown in Table 1.
Methods Over the first 3 months, we filmed (using a video camera Sony Hi8) mare-foal pairs once a week, after which we filmed them once a month.
Our goal was to obtain a minimum of 15-minute samples of videotaping per pair and a minimum of two pairs per week, and later per month.
For the Peruvian mares with Peruvian foals, we were able to meet this objective until the foals’ reached nine months of age, with the exception of the sixth week (table 1).
In the case of the surrogate mares with Peruvian foals, we obtained data over a total of five weeks between birth and the ninth week (Table 1).
In order to avoid any confusion in recognizing members of a pair and since distances are hard to evaluate on video, each time we filmed a new pair, we recorded orally, on the video, which pair we were filming and at what distance they were from each other (based on two or three observers’ visual estimations and occasionally walking the distance), updating this information as changes occurred.
The videos were then analyzed in the laboratory.
For each pair we recorded the distance between a foal and its mother every 30 seconds within each video-sample.
We used the 5m criterion used by Smith-Funk and Crowell- Davis (1992, also see Tyler, 1972, in Waring, 1983), that is, whether foals were within a 5m radius of their mothers or at more than 5m.
We also took note each time a foal was nursing, within a 30-second period for each video-sample.
We calculated percentages of the time each foal spent within a 5m radius of its mother and of the time spent nursing.
The Wilcoxon-Mann-Whitney test was used for inter-group comparisons with respect to distance to mother and nursing time during the age categories for which data was available for both groups (Siegel and Castellan, 1988). Results — Peruvian mare – Peruvian foal min filmed per pair Age of foal 0 to 1 wk 1 to 2 wk 2 to 3 wk 3 to 4 wk 4 to 5 wk 5 to 6 wk 7 to 8 wk 8 to 9 wk 9 to 10 wk 10 to 11 wk 11 to 12 wk 3 to 4 mo 4 to 5 mo 5 to 6 mo 6 to 7 mo 7 to 8 mo 8 to 9 mo n 10 9 4 6 6 3 5 5 3 4 6 4 4 4 3 3 3 mean ± 1SE 24.7 ± 3.1 22.2 ± 1.5 24.4 ± 6.0 21.7 ± 2.5 25.9 ± 4.4 25.8 ± 2.1 21.9 ± 3.1 18.5 ± 1.7 19.2 ± 1.0 20.5 ± 1.7 20.1 ± 1.5 25.6 ± 5.8 21.9 ± 3.6 18.6 ± 2.5 38.0 ± 11.1 27.3 ± 10.4 20.0 ± 5.0 % “0 to 5m” mean ± 1SE 99.5 ± 0.4 95.9 ± 2.4 90.6 ± 5.6 90.5 ± 5.1 77.1 ± 10.8 70.6 ± 10.3 85.1 ± 7.4 80.2 ± 9.8 96.6 ± 2.3 85.2 ± 8.0 78.3 ±10.7 87.6 ± 7.9 96.7 ± 3.3 82.0 ± 10.2 66.4 ± 23.2 60.5 ± 25.5 60.5 ± 19.8 % “suckling” mean ± 1SE 17.2 ± 2.8 18.0 ± 3.0 14.6 ± 6.9 11.8 ± 1.9 6.2 ± 1.4 8.5 ± 1.9 7.6 ± 1.8 2.4 ± 1.9 5.1 ± 2.8 8.2 ± 3.9 0±0 5.2 ± 3.9 5.4 ± 2.7 4.3 ± 1.8 3.9 ± 0.7 7.5 ± 2.7 0±0 Surrogate regional mare – Peruvian foal min filmed per pair n 3 4 2 3 2 mean ± 1SE 40.5 ± 11.6 88.2 ± 15.9 83.7 ± 21.2 111.2 ± 4.3 100.2 ± 1.7 % “0 to 5m” mean ± 1SE 100 ± 0 94.1 ± 2.1 70.6 ± 19.4 78.2 ± 4.6 81.6 ± 1.7 % “suckling” mean ± 1SE 15.9 ± 3.6 11.6 ± 2.0 5.3 ± 1.3 6.9 ± 0.3 5.3 ± 2.8 similar results in our two groups, 99.5 and 100%, respectively.
Foals of both groups then started to spend less time close to their mothers but this decrease was not linear.
By the eighth month, foals of the Peruvian-only group still spent a lot of time within a 5m radius of their mothers (60%).
Nursing episodes decreased in the two groups, especially after the first month.
This is to be expected and it has been reported in a variety of other breeds, eg, Tyler (1972, in Waring, 1983) in the New Forest ponies, Duncan et al. (1984) in a band of free-ranging horses from Camargue, France, Crowell-Davis (1985) in Welsh ponies, and Barber and Crowell-Davis (1994) in Belgian horses.
We found no significant differences between the two groups with respect to distance to mother and time spent nursing even though in one group the mother was biological and in the other the mother was a surrogate mare from another breed.
Separation of mother and foal is similar among horse breeds (Waring, 1983), including feral horses (Duncan et al., 1984).
It has also been reported in Welsh ponies (Crowell-Davis, 1985), in mules (Smith-Funk and Crowell-Davis, 1992), in donkeys (French, 1998) and now in the special case of foals raised by surrogate mothers of another breed.
In feral horses, complete weaning occurs toward the end of the first year, usually coincident with the mare giving birth to a new foal (Waring, 1983, and references therein).
However, nursing may continue until the foal’s second summer if the mother does not foal that year. Our data agree with findings in reports on other breeds of horses.
In the two groups we studied, foals spent about 80% of their time close to their mothers at two months of age, with Peruvian foals raised by their biological mothers maintaining this close contact until 6 months of age after which the time spent with the mother decreased to about two-thirds.
These results suggest, on one hand, that separation in horses is similar in many breeds, including the particular case of foals raised by surrogate mothers of another breed, and on the other, that this process is long, at least 8 months or longer, indicating long-term bonding between mares and their foals.
This may be important to consider in light of horse management and in particular with respect to appropriate time for weaning. Acknowledgements.
The authors wish to acknowledge the help provided by Cristian Abdala, José María Chani, Ada Echeverría, and Javier Fiaño.
We thank Coqui de la Jara for his help and his support and Raúl Chacón and Hugo Mario Velardez for allowing us to observe and film their horses on their farms.
We are grateful to José María Chani, Ada Echeverría, Silvia Moro, and to anonymous reviewers for comments on the manuscript. References Ascásubi de, L., 1968.
El Caballo de Paso y su Equitación.
Asociación Nacional de Criadores y Propietarios de Caballos Peruanos de Paso.
A. & Crowell-Davis, S.
Maternal behavior of Belgian (Equus caballus ) mares.
Nursing behaviour and maternal 26 Halloy et al: mare-foal interactions in horses aggression among Welsh ponies (Equus caballus ).
Spatial relations between mares and foals of the Welsh pony ( Equus caballus ).
Behav. , 34:10071015.
Duncan, P., Harvey, P.
H., & Wells, S.
On lactation and associated behaviour in a natural herd of horses.
Behav. , 32:255-263.
Estep, D.Q., Crowell-Davis, S.L., Earl-Costello, S.
A., & Beatey, S.
Changes in the social behaviour of drafthorse ( Equus caballus ) mares coincident with foaling.
Origen del paso peruano.
Libertad E.I.R.L., Peru. French, J.
Mother-offspring relationships in donkeys.
M. & Poulin, A., 2002.
Equid play ethogram.
Siegel, S. & Castellan, N.
Nonparametric Statistics for the Behavioral Sciences.
McGraw Hill, Inc., New York, 399pp.
D. & Crowell-Davis, S.
Maternal behavior of draft mares ( Equus caballus ) with mule foals ( Equus asinus x Equus caballus ).
The behaviour and social organization of the New Forest ponies.
Horse Behavior: The Behavioral Traits and Adaptations of Domestic and Wild Horses, Including Ponies.
Noyes Publications, Park Ridge, New Jersey, 290p.
Read more about Equus : Introduction Although several studies have reported on motheryoung interactions in….: