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Effects of a post-partum separation on maternal responsiveness in primiparous and multiparous domestic goats
Applied Animal Ethology, 8 (1982) 537-542 Elsevier Scientific Publishing Company, Amsterdam
- Printed
in The
Netherlands
537
EFFECTS OF A POST-PARTUM SEPARATION ON MATERNAL RESPONSIVENESS IN PRIMIPAROUS AND MULTIPAROUS DOMESTIC GOATS
ROBERT
E. LICKLlTER
Animal Behavior Graduate Group, Department California, Davis, CA 95616 (U.S.A.) (Accepted
for publication
of Animal
Science, University of
25 June 1981)
ABSTRACT Lickliter, R.E., 1982. Effects of a postpartum separation on maternal responsiveness primiparous and multiparous domestic goats. Appl. Anim. Ethol., 8: 537-542.
in
This study assessed the effects of a two-hour postpartum separation on the development of maternal behavior in the domestic goat. Results contrasted with previous findings and indicate that goat mothers may display maternal caretaking behavior towards their kids despite an immediate postpartum separation of mother and young. The duration of unsolicited maternal responsiveness varied between individuals; in particular, a marked difference w&s observed in the responses of experienced and non-experienced goat mothNersto the separation. The data suggest that previous reproductive experience may serve :to increase the likelihood of activation and maintenance of maternal responsiveness in domestic goats. INTRODUCTION
In most ungulate species, a period of intense reciprocal stimulation between mother and young is seen almost immediately following parturition (Lent, 1974). It is believed that the movements, odors and vocalizations of the ungulate neonate serve to attract the female; likewise, the female is thought to present the newborn with a variety of tactual, thermal, visual and auditory stimuli. This complex interchange associated with the post-partum period has been suggested to be the basis for the development of ungulate socialization (Schneirla and Rosenblatt, 1961). The relatively rapid and effective development of the mother--young bond in the domestic goat has been investigated in a number of studies. Blauvelt (1955) and Collias (1956) were among the first to describe parturition in the species; both noted that goat mothers typically form a specific bond to their newborn very soon after parturition and thereafter reject all alien young, which are readily distinguished from own kids. Several studies have suggested that there exists a “critical period” for the development of this stable, specific mother-young bond (Klopfer, 1971; Klopfer and
0304-3762/82/0000-0000/$02.75
0 1982 Elsevier
Scientific
Publishing
Company
538
Klopfer, 1968). These studies indicate that the experiences of the goat mother immediately following parturition can be critical to the establishment of a stable bond to the newborn. In addition, three separate studies (Collias, 1956; Hersher et al., 1958; Klopfer et al., 1964) reported that separation of mother and young for a short time following birth results in an absence of observable maternal behavior when the goat mother and her separated kids are reunited. The data also suggest that the sooner after birth that such an experimental separation occurs, the more obvious and consistent are the effects. For example, the Klopfer et al. (1964) study indicated that goat mothers whose young were removed immediately upon emergence from the birth canal rejected their kids upon reunion l-3 h later. In contrast, control mothers who were allowed as little as 5 min of contact with their kids immediately following delivery, and then separated for l--3 h, accepted their young upon reunion. The study reports no difference between primiparous and multiparous goat mothers following the experimental separation, and suggests that something happens in the space of a few minutes after birth which makes the goat mother ready to accept and attach herself to her kids. My own observations of parturient goat females and their young, made over a period of several years, suggested to me that the length of time a mother would remain responsive despite a separation from her newborn was much more variable than the literature would suggest. In particular, it seemed that the duration of unsolicited maternal responsiveness was often related to the goat mother’s previous history of birthing and caretaking. Although it has long been known that maternal behavior is more efficient in multiparous than in primiparous females for a wide variety of mammals (Rheingold, 1963; LeBouef et al., 1972; Alexander et al., 1974), and that prior exposure to young may serve to sensitize mothers to subsequent offspring (Lehrman, 1962; Noirot, 1964), little or no work has been done on the extent to which previous reproductive experience may contribute to the expression of maternal behavior in the domestic goat. This paucity of information stimulated this study. SUBJECTS AND METHODS
Twenty-four goats (Toggenburg and Saanen strains) were divided into 2 test groups, equated for breed, age and parity. The first group of does, birth and known as the control group (n=12), was allowed an uninterrupted postpartum period and was not subjected to any experimental manipulation. Their post-partum behavior was observed and recorded in writing, stillphotography, and in some cases on 16-mm film by a time-lapse camera (Milliken DBM 54) at a film speed of 2 frames/s. Observation began with the expulsion of the first-born and ended one hour later. The other group of does, known as the immediately separated group (n= 12), was deprived of all contact with their young following delivery. The
539
kids were caught as they emerged from the birth canal, removed from the barn, and placed in an isolated pen where they were cleaned of all birth fluids with clean towels and left under a heat lamp for a 2-h separation period. The mother was allowed to remain at the birth site, but all birth fluids and fetal membranes were removed following expulsion to minimize olfactory cues. After the 2-h separation, the newborn were returned to their mother’s side. Observations of initial mother-young contact were recorded as above, commencing with the return of the kids and ending one hour later. Other than for the experimental separation procedures, the usual life of the goat herd was not disturbed. All 24 does were allowed to choose their own birth sites within the barn in which they normally live, and all does remained in the herd group before, during and after parturition. The human observer and the filming equipment were located l-3 m outside the goat stalls, and were familiar to the animals prior to the onset of the study. To facilitate observation, all females were marked and identified by numbered collars.
Scoring The following variables were recorded for each goat mother during their first hour of mother-infant contact: (1) latency for the female to begin to groom her kids; (2) latency for the female to successfully suckle her kids; (3) number of times the female avoided or withdrew from the nursing attempts of her kids; (4) average proximity of the female to her kids. To facilitate scoring, the following definitions were employed: (1) grooming was defined as the discrete licking of the kid’s fur by the mother; (2) suckling was defined as kid oral contact with the mother’s teat; (3) withdrawal/avoidance was defined as the mother increasing the distance from her kids, with her body turned away from them. Rejection of young was scored when persistent withdrawal from, or active avoidance of, the young and the refusal to stand and suckle the kids were observed. Acceptance of young was scored when grooming the young and allowing them to nurse were observed. RESULTS
Recorded results are summarized in Table I. There was a significant correlation between separation from young and subsequent rejection of young (x’ = 4.04;~ < 0.05; 1 df.). All 12 control goat mothers accepted their newborn immediately following parturition, while only 7 of the immediatelyseparated goat mothers accepted their kids at reunion following the 2-h separation. In all 12 control does, vigorous licking and grooming of the newborn began at once following delivery and persisted throughout the one-hour observation period. Control does were seen to lick and groom their kids while
540 TABLE I Comparison of maternal behavior between control and immediately-separated females Goat No.
breed
Control group T 29 T 30 T 31 S 32 s 33 s 34 T 35 T 36 T 37 T 38 s 39 s 40
age
parity
Latency to first groom kids (s)
Latency to first suckle kids (min)
Frequenof withdrawals
2 2 3 2 3 5 1 1 1 1 1 2
M M M M M M P P P P P P
22 05 12 07 10 23 15 93 21 17 07 33
45 37 53 54 21 47 43 55 48 31 57 42
0 0 0 0 0 0
Immediately-separated erou~ -05 T i M41 04 42 T 2 M 04 43 T 6 M 12 44 S 2 M 05 45 S 3 M 20 46 S 4 M 07 47 T 1 P T 1 P Did 48 T 49 1 P Did S 1 P Did 50 51 s 1 P Did S 2 P Did 52
not not not not not
occur occur occur occur occur
46 31 17 22 54 43 22 Did Did Did Did Did
1 0 0 0 2 0
0 0 0 0 0 0
not not not not not
occur occur occur occur occur
1 8 4 7 3 9
Mean distance from kids (m)
Score
O-l
Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted
O-l O-l O-l O-l O-l O-l O--l O--l O-l O-l O-l
O-l
O-l O-l O-l O-l O-l O-l 4-5 4-5 5-6 4-5 56
Accepted Accepted Accepted Accepted Accepted Accepted Accepted Rejected Rejected Rejected Rejected Rejected
standing and reclining, as well as when their kids were recumbent, standing and on the move about them. No kids of control does were seen to stand or suckle without first being licked by their mothers. Maternal postural changes, which apparently facilitate teat-seeking by the young, were observed in all 12 controls, including rotating and orienting the body to face the newborn and arching the spine into a crouching position to bring the udder closer to the.kids. All controls allowed sustained kid contact with the udder, and all suckled their kids within the first hour following parturition. Of the 12 does temporarily deprived of all contact with their young following birth, 7 accepted their kids at reunion. These mothers showed immediate interest in their kids and displayed the maternal caretaking patterns described above, including grooming, orienting and allowing sustained kid con-
541
tact with the udder. In contrast, 5 of the immediately-separated does rejected their kids following the 2-h separation. All 5 rejecting goat mothers were primipara. On the return of their kids, all 5 primiparous does immediately withdrew from their young and thereafter actively avoided any approaches made by their kids. None of these primiparous mothers were seen to lick or groom their kids during the one-hour observation period, and all refused to stand and suckle their young. DISCUSSION
These results clearly show that maternal rejection is not an inevitable consequence of postpartum separation in the domestic goat. In contrast to earlier findings, the data indicate that a short period of contact between a goat mother and her young immediately following parturition is not necessary for the later display of maternal responsiveness, except in some primipara. That the primiparous goat mother is able to display adequate maternal behavior is indicated by the immediate caretaking behavior performed by all 6 primiparous control does. Although obviously non-essential to the expression of maternal behavior, it seems that previous reproductive experience may serve to make the multiparous goat mother more sensitive to her young following a temporary separation, and also make her more likely to respond to them in an appropriate fashion following reunion. Similar findings have been reported in other domesticated ungulate species, including sheep (Alexander et al., 1974) and cattle (Selman et al., 1970). These results imply that the maternal responsiveness of the multiparous goat mother is not equivalent in all circumstances to that of the primiparous mother; there appear to be conditions under which the primiparous female will fail to respond maternally, while the multiparous female will respond in an adequate fashion. Impairment of, or interference with, one or more sources of mother-infant contact following birth does not necessarily prevent the display of maternal behavior, but it may influence the expression of maternal responsiveness in non-experienced goat mothers, as indicated by an absence of grooming behavior, the refusal to stand and nurse, and desertion of kids. Hafez (1964) emphasized the differences seen in the nursing behavior of primiparous and multiparous females. He stated that “nursing behavior in older animals appears to be facilitated by the reflexes conditioned during previous lactation, and in the primiparous animals may be inhibited by the pain and shock of parturition”. The findings of this study support this contention for domestic goats as well, and point to the importance of close supervision when parturient goat females are exposed to human disturbance. Temporary disruption of normal mother--infant post-pa&urn interaction may cause a breakdown in the relationship between mother and kid and may even result in newborn mortality due to starvation or exposure.
542 ACKNOWLEDGEMENTS
The study was partially funded by a Chancellor’s Patent Fund Research Grant from the University of California, Davis. I am grateful to Drs. L.V. Harper and E.O. Price for critically reviewing earlier drafts of this manuscript.
REFERENCES Alexander, G., Signoret, J.P. and Hafez, E.S.E., 1974. Sexual and maternal behavior. In: E.S.E. Hafez (Editor), Reproduction in Farm Animals. Lea and Febiger, Philadelphia, pp. 222-254. Blauvelt, H., 1955. Dynamics of the mother-newborn relationship in goats. In: B. Schaffer (Editor), Group Processes. Josiah Macy Jr. Foundation, New York, pp. 221258. Collias, N.E., 1956. The analysis of socialization in sheep and goats. Ecology, 37: 229239. Hafez, E.S.E., 1964. Some physiological and behavioral responses of the neonate. Cornell Vet., 59: 545-560. Hersher, L., Moore, A.U. and Richmond, J.B., 1958. Effect of postpartum separation of mother and kid on maternal care in the domestic goat. Science, 128: 1342-1343. Klopfer, P.H., 1971, Mother-love: What turns it on? Am. Sci., 59: 404-407. Klopfer, P.H. and Klopfer, M.S., 1968. Maternal “imprinting” in goats: Fostering of alien young. 2. Tierpsychol., 25: 862-866. Klopfer, P.H., Adams, D.K. and Klopfer, M.S., 1964. Maternal “imprinting” in goats. Proc. Natl. Acad. Sci., 52: 911-914. LeBouef, B.J., Whiting, R.J. and Gantt, R.F., 1972. Perinatal behaviour of northern elephant seal females and their young. Behaviour, 43: 121-156. Lehrman, D.S., 1962. Interaction of hormonal and experiential influences on development of behavior. In: E.L. Bliss (Editor), Roots of Behavior. Harper and Brothers, New York, pp. 142-156. Lent, P.C., 1974. Mother-infant relationships in ungulates. In: V. Geist and F. Walther (Editors), Behavior of Ungulates and its Relation to Management. IUCN, Morges, Switzerland, pp. 15-55. Noirot, E., 1964. Changes in responsiveness to young in the adult mouse. Anim. Bebav., 12: 52.-58. Rheingold, H., 1963. Maternal Behavior in Mammals. John Wiley, New York. Schneirla, T.C. and Rosenblatt, J.S., 1961. Behavioral organization and genesis of the social bond in insects and mammals. Am. J. Orthopsychol., 31: 223-253. Selman, I.E., McEwan, A.I. and Fisher, E.W., 1970. Studies on natural suckling in cattle during the first eight hours postpartum. Anim. Behav., 18: 276-283.
- Printed
in The
Netherlands
537
EFFECTS OF A POST-PARTUM SEPARATION ON MATERNAL RESPONSIVENESS IN PRIMIPAROUS AND MULTIPAROUS DOMESTIC GOATS
ROBERT
E. LICKLlTER
Animal Behavior Graduate Group, Department California, Davis, CA 95616 (U.S.A.) (Accepted
for publication
of Animal
Science, University of
25 June 1981)
ABSTRACT Lickliter, R.E., 1982. Effects of a postpartum separation on maternal responsiveness primiparous and multiparous domestic goats. Appl. Anim. Ethol., 8: 537-542.
in
This study assessed the effects of a two-hour postpartum separation on the development of maternal behavior in the domestic goat. Results contrasted with previous findings and indicate that goat mothers may display maternal caretaking behavior towards their kids despite an immediate postpartum separation of mother and young. The duration of unsolicited maternal responsiveness varied between individuals; in particular, a marked difference w&s observed in the responses of experienced and non-experienced goat mothNersto the separation. The data suggest that previous reproductive experience may serve :to increase the likelihood of activation and maintenance of maternal responsiveness in domestic goats. INTRODUCTION
In most ungulate species, a period of intense reciprocal stimulation between mother and young is seen almost immediately following parturition (Lent, 1974). It is believed that the movements, odors and vocalizations of the ungulate neonate serve to attract the female; likewise, the female is thought to present the newborn with a variety of tactual, thermal, visual and auditory stimuli. This complex interchange associated with the post-partum period has been suggested to be the basis for the development of ungulate socialization (Schneirla and Rosenblatt, 1961). The relatively rapid and effective development of the mother--young bond in the domestic goat has been investigated in a number of studies. Blauvelt (1955) and Collias (1956) were among the first to describe parturition in the species; both noted that goat mothers typically form a specific bond to their newborn very soon after parturition and thereafter reject all alien young, which are readily distinguished from own kids. Several studies have suggested that there exists a “critical period” for the development of this stable, specific mother-young bond (Klopfer, 1971; Klopfer and
0304-3762/82/0000-0000/$02.75
0 1982 Elsevier
Scientific
Publishing
Company
538
Klopfer, 1968). These studies indicate that the experiences of the goat mother immediately following parturition can be critical to the establishment of a stable bond to the newborn. In addition, three separate studies (Collias, 1956; Hersher et al., 1958; Klopfer et al., 1964) reported that separation of mother and young for a short time following birth results in an absence of observable maternal behavior when the goat mother and her separated kids are reunited. The data also suggest that the sooner after birth that such an experimental separation occurs, the more obvious and consistent are the effects. For example, the Klopfer et al. (1964) study indicated that goat mothers whose young were removed immediately upon emergence from the birth canal rejected their kids upon reunion l-3 h later. In contrast, control mothers who were allowed as little as 5 min of contact with their kids immediately following delivery, and then separated for l--3 h, accepted their young upon reunion. The study reports no difference between primiparous and multiparous goat mothers following the experimental separation, and suggests that something happens in the space of a few minutes after birth which makes the goat mother ready to accept and attach herself to her kids. My own observations of parturient goat females and their young, made over a period of several years, suggested to me that the length of time a mother would remain responsive despite a separation from her newborn was much more variable than the literature would suggest. In particular, it seemed that the duration of unsolicited maternal responsiveness was often related to the goat mother’s previous history of birthing and caretaking. Although it has long been known that maternal behavior is more efficient in multiparous than in primiparous females for a wide variety of mammals (Rheingold, 1963; LeBouef et al., 1972; Alexander et al., 1974), and that prior exposure to young may serve to sensitize mothers to subsequent offspring (Lehrman, 1962; Noirot, 1964), little or no work has been done on the extent to which previous reproductive experience may contribute to the expression of maternal behavior in the domestic goat. This paucity of information stimulated this study. SUBJECTS AND METHODS
Twenty-four goats (Toggenburg and Saanen strains) were divided into 2 test groups, equated for breed, age and parity. The first group of does, birth and known as the control group (n=12), was allowed an uninterrupted postpartum period and was not subjected to any experimental manipulation. Their post-partum behavior was observed and recorded in writing, stillphotography, and in some cases on 16-mm film by a time-lapse camera (Milliken DBM 54) at a film speed of 2 frames/s. Observation began with the expulsion of the first-born and ended one hour later. The other group of does, known as the immediately separated group (n= 12), was deprived of all contact with their young following delivery. The
539
kids were caught as they emerged from the birth canal, removed from the barn, and placed in an isolated pen where they were cleaned of all birth fluids with clean towels and left under a heat lamp for a 2-h separation period. The mother was allowed to remain at the birth site, but all birth fluids and fetal membranes were removed following expulsion to minimize olfactory cues. After the 2-h separation, the newborn were returned to their mother’s side. Observations of initial mother-young contact were recorded as above, commencing with the return of the kids and ending one hour later. Other than for the experimental separation procedures, the usual life of the goat herd was not disturbed. All 24 does were allowed to choose their own birth sites within the barn in which they normally live, and all does remained in the herd group before, during and after parturition. The human observer and the filming equipment were located l-3 m outside the goat stalls, and were familiar to the animals prior to the onset of the study. To facilitate observation, all females were marked and identified by numbered collars.
Scoring The following variables were recorded for each goat mother during their first hour of mother-infant contact: (1) latency for the female to begin to groom her kids; (2) latency for the female to successfully suckle her kids; (3) number of times the female avoided or withdrew from the nursing attempts of her kids; (4) average proximity of the female to her kids. To facilitate scoring, the following definitions were employed: (1) grooming was defined as the discrete licking of the kid’s fur by the mother; (2) suckling was defined as kid oral contact with the mother’s teat; (3) withdrawal/avoidance was defined as the mother increasing the distance from her kids, with her body turned away from them. Rejection of young was scored when persistent withdrawal from, or active avoidance of, the young and the refusal to stand and suckle the kids were observed. Acceptance of young was scored when grooming the young and allowing them to nurse were observed. RESULTS
Recorded results are summarized in Table I. There was a significant correlation between separation from young and subsequent rejection of young (x’ = 4.04;~ < 0.05; 1 df.). All 12 control goat mothers accepted their newborn immediately following parturition, while only 7 of the immediatelyseparated goat mothers accepted their kids at reunion following the 2-h separation. In all 12 control does, vigorous licking and grooming of the newborn began at once following delivery and persisted throughout the one-hour observation period. Control does were seen to lick and groom their kids while
540 TABLE I Comparison of maternal behavior between control and immediately-separated females Goat No.
breed
Control group T 29 T 30 T 31 S 32 s 33 s 34 T 35 T 36 T 37 T 38 s 39 s 40
age
parity
Latency to first groom kids (s)
Latency to first suckle kids (min)
Frequenof withdrawals
2 2 3 2 3 5 1 1 1 1 1 2
M M M M M M P P P P P P
22 05 12 07 10 23 15 93 21 17 07 33
45 37 53 54 21 47 43 55 48 31 57 42
0 0 0 0 0 0
Immediately-separated erou~ -05 T i M41 04 42 T 2 M 04 43 T 6 M 12 44 S 2 M 05 45 S 3 M 20 46 S 4 M 07 47 T 1 P T 1 P Did 48 T 49 1 P Did S 1 P Did 50 51 s 1 P Did S 2 P Did 52
not not not not not
occur occur occur occur occur
46 31 17 22 54 43 22 Did Did Did Did Did
1 0 0 0 2 0
0 0 0 0 0 0
not not not not not
occur occur occur occur occur
1 8 4 7 3 9
Mean distance from kids (m)
Score
O-l
Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted Accepted
O-l O-l O-l O-l O-l O-l O--l O--l O-l O-l O-l
O-l
O-l O-l O-l O-l O-l O-l 4-5 4-5 5-6 4-5 56
Accepted Accepted Accepted Accepted Accepted Accepted Accepted Rejected Rejected Rejected Rejected Rejected
standing and reclining, as well as when their kids were recumbent, standing and on the move about them. No kids of control does were seen to stand or suckle without first being licked by their mothers. Maternal postural changes, which apparently facilitate teat-seeking by the young, were observed in all 12 controls, including rotating and orienting the body to face the newborn and arching the spine into a crouching position to bring the udder closer to the.kids. All controls allowed sustained kid contact with the udder, and all suckled their kids within the first hour following parturition. Of the 12 does temporarily deprived of all contact with their young following birth, 7 accepted their kids at reunion. These mothers showed immediate interest in their kids and displayed the maternal caretaking patterns described above, including grooming, orienting and allowing sustained kid con-
541
tact with the udder. In contrast, 5 of the immediately-separated does rejected their kids following the 2-h separation. All 5 rejecting goat mothers were primipara. On the return of their kids, all 5 primiparous does immediately withdrew from their young and thereafter actively avoided any approaches made by their kids. None of these primiparous mothers were seen to lick or groom their kids during the one-hour observation period, and all refused to stand and suckle their young. DISCUSSION
These results clearly show that maternal rejection is not an inevitable consequence of postpartum separation in the domestic goat. In contrast to earlier findings, the data indicate that a short period of contact between a goat mother and her young immediately following parturition is not necessary for the later display of maternal responsiveness, except in some primipara. That the primiparous goat mother is able to display adequate maternal behavior is indicated by the immediate caretaking behavior performed by all 6 primiparous control does. Although obviously non-essential to the expression of maternal behavior, it seems that previous reproductive experience may serve to make the multiparous goat mother more sensitive to her young following a temporary separation, and also make her more likely to respond to them in an appropriate fashion following reunion. Similar findings have been reported in other domesticated ungulate species, including sheep (Alexander et al., 1974) and cattle (Selman et al., 1970). These results imply that the maternal responsiveness of the multiparous goat mother is not equivalent in all circumstances to that of the primiparous mother; there appear to be conditions under which the primiparous female will fail to respond maternally, while the multiparous female will respond in an adequate fashion. Impairment of, or interference with, one or more sources of mother-infant contact following birth does not necessarily prevent the display of maternal behavior, but it may influence the expression of maternal responsiveness in non-experienced goat mothers, as indicated by an absence of grooming behavior, the refusal to stand and nurse, and desertion of kids. Hafez (1964) emphasized the differences seen in the nursing behavior of primiparous and multiparous females. He stated that “nursing behavior in older animals appears to be facilitated by the reflexes conditioned during previous lactation, and in the primiparous animals may be inhibited by the pain and shock of parturition”. The findings of this study support this contention for domestic goats as well, and point to the importance of close supervision when parturient goat females are exposed to human disturbance. Temporary disruption of normal mother--infant post-pa&urn interaction may cause a breakdown in the relationship between mother and kid and may even result in newborn mortality due to starvation or exposure.
542 ACKNOWLEDGEMENTS
The study was partially funded by a Chancellor’s Patent Fund Research Grant from the University of California, Davis. I am grateful to Drs. L.V. Harper and E.O. Price for critically reviewing earlier drafts of this manuscript.
REFERENCES Alexander, G., Signoret, J.P. and Hafez, E.S.E., 1974. Sexual and maternal behavior. In: E.S.E. Hafez (Editor), Reproduction in Farm Animals. Lea and Febiger, Philadelphia, pp. 222-254. Blauvelt, H., 1955. Dynamics of the mother-newborn relationship in goats. In: B. Schaffer (Editor), Group Processes. Josiah Macy Jr. Foundation, New York, pp. 221258. Collias, N.E., 1956. The analysis of socialization in sheep and goats. Ecology, 37: 229239. Hafez, E.S.E., 1964. Some physiological and behavioral responses of the neonate. Cornell Vet., 59: 545-560. Hersher, L., Moore, A.U. and Richmond, J.B., 1958. Effect of postpartum separation of mother and kid on maternal care in the domestic goat. Science, 128: 1342-1343. Klopfer, P.H., 1971, Mother-love: What turns it on? Am. Sci., 59: 404-407. Klopfer, P.H. and Klopfer, M.S., 1968. Maternal “imprinting” in goats: Fostering of alien young. 2. Tierpsychol., 25: 862-866. Klopfer, P.H., Adams, D.K. and Klopfer, M.S., 1964. Maternal “imprinting” in goats. Proc. Natl. Acad. Sci., 52: 911-914. LeBouef, B.J., Whiting, R.J. and Gantt, R.F., 1972. Perinatal behaviour of northern elephant seal females and their young. Behaviour, 43: 121-156. Lehrman, D.S., 1962. Interaction of hormonal and experiential influences on development of behavior. In: E.L. Bliss (Editor), Roots of Behavior. Harper and Brothers, New York, pp. 142-156. Lent, P.C., 1974. Mother-infant relationships in ungulates. In: V. Geist and F. Walther (Editors), Behavior of Ungulates and its Relation to Management. IUCN, Morges, Switzerland, pp. 15-55. Noirot, E., 1964. Changes in responsiveness to young in the adult mouse. Anim. Bebav., 12: 52.-58. Rheingold, H., 1963. Maternal Behavior in Mammals. John Wiley, New York. Schneirla, T.C. and Rosenblatt, J.S., 1961. Behavioral organization and genesis of the social bond in insects and mammals. Am. J. Orthopsychol., 31: 223-253. Selman, I.E., McEwan, A.I. and Fisher, E.W., 1970. Studies on natural suckling in cattle during the first eight hours postpartum. Anim. Behav., 18: 276-283.