Factors influencing maternal and filial behavior in goats of the Azul genetic group raised in the semi-arid tropicsABSTRACT
Our study investigated the mother-offspring relationship in the Grupo Genético Azul goat from lambing until 24 hours after lambing. We observed 40 adult goats with an average live weight of 34.8±1.36kg. Continuous focal sampling of the animals was conducted after calving and every 6 hours for 24 hours. The observers were outside the goats' environment, at a distance to avoid interfering with the results; prior to this, the goats had been in contact with the observers and were therefore used to their presence. Regarding grazing (P<.0001), lying down (P<.0001), and bucking (P=0.0034), these variables showed significant differences over time. After giving birth and up to 24 hours later, the goats exhibited certain behaviors more frequently, such as looking at the kid, bleating, and sniffing the kids. These behaviors were more evident immediately after parturition, gradually reducing over time, but remaining relevant for up to 24 hours. Allotrophic and agonistic behaviors were not observed. In conclusion, the data reinforces that maternal behavior plays a crucial role in the survival and healthy development of kids, especially in the first hours after birth.
Keywords:
breastfeeding; hardiness; native breed; vocalization
RESUMO
Este estudo investigou a relação mãe-filho em cabras do grupo genético Azul, desde o parto até 24 horas após. Foram observadas 40 cabras adultas, com peso vivo médio de 34,8 ± 1,36kg. Amostragens focais contínuas dos animais foram realizadas após o parto e a cada 6 horas até 24 horas após o parto. Os observadores estavam fora do ambiente das cabras, a uma distância suficiente para não interferir nos resultados; antes disso, as cabras tinham contato com os observadores e, portanto, estavam acostumadas à sua presença. Com relação a pastejar (P<0,0001), deitar (P<0,0001) e empinar (P=0,0034), essas variáveis apresentaram diferenças significativas ao longo do tempo. Após o parto e até 24 horas depois, as cabras exibiram certos comportamentos com mais frequência, como olhar para os cabritos, balir e cheirá-los. Esses comportamentos foram mais evidentes imediatamente após o parto, reduzindo-se gradualmente ao longo do tempo, mas permanecendo relevantes por até 24 horas. Comportamentos alótrofos e agonísticos não foram observados. Em conclusão, os dados reforçam que o comportamento materno desempenha papel crucial na sobrevivência e no desenvolvimento saudável dos filhotes, especialmente nas primeiras horas após o nascimento.
Palavras-chave:
amamentação; raça nativa; rusticidade; vocalização
INTRODUCTION
In arid and semi-arid regions, small ruminants are raised in extensive systems, using native vegetation as their main food source, allowing goats and kids to remain together from birth to weaning (Fonseca et al., 2016; Leite et al., 2021). Among behavioral patterns that contribute to reproductive success, none is more important than maternal behavior, which directly affects the care and survival of offspring, particularly in harsh conditions (Putu et al., 1988).
Native goat breeds have valuable genetic material suited to semi-arid conditions. One standout genetic group is Azul, or Azulanha, characterized by bluish-gray fur and dark skin, although it is not officially recognized as a breed. This group is at risk of extinction, but there is potential for recovering this important genetic material, which, despite the degenerative acclimatization process, retains rich yet underexplored genetic traits. These include drought and disease resistance, as well as maternal ability. Additionally, they are non-seasonal polyestrous, allowing year-round kid production.
Behavior plays a fundamental role in adaptation to the environment through natural selection (Atkin-Willoughby et al., 2022). Understanding the ethogram of motivated behaviors, such as reproductive and parental behaviors, helps us understand how a population adapts to its environment (Pritchard et al., 2021). Maternal-filial behavior is defined as actions taken by parents that increase their offspring's ability to survive and reproduce while reducing the parents' ability to invest in future offspring (Trivers, 1974). In recent years, observations of animal behavior have contributed not only to animal management but also to reducing stress resulting from the intense productive exploitation of herds.
Several factors can alter the maternal-filial relationship between goats and their kids, including the timing of first contact, ewe nutrition, type of calving, and kid birth order. The latter significantly influences the initial development of kids, as primiparous ewes tend to be more stressed during the early stages of the maternal-filial relationship (Porciuncula et al., 2021; Dada et al., 2022; Casian et al., 2024).
The high mortality rate of kids before weaning has been a global problem, ranging from 15-20% (Flinn et al., 2020), negatively affecting goat production. The postpartum period in goats is characterized by intense behavioral interaction between the ewe and newborn kids (Dwyer and Lawrence, 1998; Dwyer, 2003). The kids' initial behaviors are typically directed toward the mother, with extremely close spatial associations between them during the first three days of life (Morgan and Arnold, 1974). Our study investigated the mother-offspring relationship in the Azul goat genetic group from lambing until 24 hours after lambing
ETHICAL ASPECTS
The research procedures were approved by the Research Ethics Committee of the Federal University of Campina Grande, Paraíba State, Brazil, CEP Protocol No. 097.2019.
MATERIAL AND METHODS
The animals were raised on family property using semi-extensive practices and were only confined during the data collection period. The goats' diet consisted mainly of natural pasture and water ad libitum, with few feed integrations, such as mixed hay, during unfavorable periods of the year. The animals' ages were estimated indirectly using dental chronology, and all were classified as adults (2-5 years old).
We observed 40 adult goats with an average live weight of 34.8±1.36kg. Estrus was not synchronized, and the goats were naturally mated with the same two Blue goats. The calving season lasted 15 days, and the goats and kids were monitored from calving until 48 hours after birth.
Only the behavior of the male goats was recorded; in total, 40 goats and kids were observed during the study. To measure changes in interactions between goats and kids, we recorded the frequency (number) of behavioral events and the duration (time) of behavioral states. For identification, the goats were numbered with non-toxic black paint on the right, left, and back sides; the kids were marked with the mother’s number (Fonseca et al., 2016).
Continuous focal sampling of the animals (Martin and Bateson, 1986) was conducted after calving and every 6 hours for 24 hours. The observers remained outside the goats’ environment, at a distance that did not interfere with the results. Prior to this, the goats had been exposed to the observers and were therefore accustomed to their presence. All data were recorded on ethograms and filmed without disturbing the goats. The records of the four observers were tested for inter-observer reliability. To test reliability, the observers watched the same video and recorded the behaviors of interest; the records were then compared, and a correlation of at least 90% was observed among observers.
The goats were kept under a semi-intensive system, with access to confinement pens and pasture areas. Behavioral observations were conducted only inside the confinement pens; no systematic records were made during grazing periods in the pasture. This methodological choice is important to clarify that the behavioral data analyzed refer exclusively to the confinement environment.
Filming was performed with digital cameras (Canon EOS Rebel T7, 24.1 MP) positioned at fixed points around the pens. A total of 4 cameras were used, placed approximately 2 m above ground at each corner of the confinement area, providing full coverage of the animals’ movements without interfering with their behavior. The recordings were later analyzed to quantify the behavioral categories.
The behavioral categories defined for the goats included:
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Time (%) spent grazing and lying down
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Number of high-pitched bleats
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Agonistic behaviors
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Number of times suckling was prevented
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Mother searching for her young
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Offspring sniffed
Additional categorical variables were recorded:
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Separation from the herd before calving (1 = no; 2 = yes)
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Intensity of agitation (1 = low; 2 = medium; 3 = high)
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Body posture at parturition (1 = lying down; 2 = standing up)
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Consumption of amniotic fluid and/or placenta (1 = no; 2 = yes)
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Facilitating breastfeeding (1 = does not facilitate; 2 = facilitates)
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Other activities during parturition (1 = no; 2 = yes)
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Sharing kids (1 = no; 2 = yes)
The maternal behavior score (MBS) was recorded approximately 12 hours after birth, when the kids were identified and weighed (O’Connor et al., 1985). This interval was adopted to avoid interference in the formation of the maternal-kid bond (Mora-Medina et al., 2016).
The goat’s reaction to human approach and restraint of the kid was assessed and classified according to a 6-point scale: 1 = goat runs away and does not return to the kid 2 = goat remains >10 m from the kid, but returns 3 = goat remains between 5-10 m from the kid(s) 4 = goat remains 1-5 m from the kid(s) 5 = goat remains up to 1 m from the kid(s) 6 = goat maintains physical contact with the kid(s).
The same evaluator scored the maternal behavior of all goats during the lambing period. The following behavioral categories were recorded for the kids: lying down, proximity to the mother, playing, number of suckling events, high-pitched bleats, and number of times the offspring sought out their mother. Additional measures were derived:
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Total number of teat access attempts = sum of successful and unsuccessful attempts
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Successful sucking (%) = (successful attempts / total attempts) × 100, considering success when the kid remained at the teat for >5 s (Fonseca et al., 2016).
The collection of climatic variables was conducted using an automatic weather station installed in the experimental area, which was positioned alongside the animals during the daytime. The sensors were mounted approximately 1.5m above ground level, following recommendations for measurements in animal production environments, to represent the animals’ occupied zone.
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Black globe temperature (Tbg): obtained using a black globe thermometer, installed at the same height as the animals, to capture the incident thermal radiation.
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Dew point temperature (Tdp): calculated from air temperature and relative humidity records, obtained by digital sensors coupled to the station.
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Wind velocity: measured every 2 hours using a portable digital anemometer, maintained at a height of 1.5 m.
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Relative humidity and ambient temperature: continuously recorded by the weather station at 15-second intervals.
From the values of Tbg and Tdp, the Black Globe Humidity Index (BGHI) was calculated according to Buffington et al. (1981), using the following equation:
where:
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TbgT= black globe temperature (°C)
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TdpT = dew point temperature (°C)
Average climatological data were used to characterize the environment during the two seasons evaluated (winter and summer), as shown in Fig. 1.
The data were analyzed using the PROC FREQ procedure in SAS OnDemand (2024), considering the different evaluation times relative to calving and 24 hours postpartum. This approach enabled a detailed analysis of the observed variables, providing a deeper understanding of behavioral changes over time.
RESULTS
Table 1 shows a general description of the goats' behavior. Most of them did not move away or remain isolated from the herd and showed little agitation. All of them remained standing in relation to their young, and no suckling behavior was identified. Placenta consumption was observed in 95% of the females, which is interesting, as this behavior helps ward off predators. As for the maternal behavior score, 80% of the goats reached a score of 6.
Regarding grazing (P<.0001), lying down (P<.0001), and bucking (P=0.0034), these variables showed significant differences as a function of time, as shown in Table 2. After giving birth and up to 24 hours later, the goats exhibited certain behaviors more frequently, such as looking at the kid, bleating, and sniffing the kids. These behaviors were more evident immediately after parturition, gradually reducing over time, but remaining relevant for up to 24 hours (Table 2). Allotrophic and agonistic behavior were not observed.
Playing behavior showed a significant difference (P=0.042) across postpartum time points. The kids spent most of the first 24 hours postpartum close to their mothers and suckling (Table 3), while play increased over time. Soon after giving birth, there were many suckling attempts, many of which were successful, possibly because the goats spent time standing next to their young, facilitating contact (Table 4).
DISCUSSION
The consumption of the placenta by 95% of females demonstrates a fundamental adaptive behavior that reduces the risk of predators, highlighting the role of natural selection. In addition, the high maternal behavior score (80% of goats achieving a score of 6) reflects strong initial interaction between mothers and their offspring, which is essential for survival and adaptation.
Early maternal care impacts the time it takes kids to attempt and succeed in standing, reaching for the udder, and suckling for the first time, which is shorter for mothers who spend less time cleaning and smelling their offspring. In contrast, the longer the goats take to clean their kids, the longer it takes for the kids to suckle for the first time. Typically, goats lick their kids until they are ready to stand, demonstrating maternal care. In the first moments after giving birth, the goat stands up, begins smelling and licking her kids, starting with the head and neck, and remains close to ingest the colostrum (Karaka et al., 2023).
According to Arnold and Morgan (1975), shortly after giving birth, the goat cleans the kids by ingesting the placental membranes and fetal fluids. Then, the kids try to stand up, which can take between 10 and 180 minutes. This behavior stimulates the kids' breathing and triggers physiological events crucial for suckling, ensuring the transfer of passive immunity.
The increase in behaviors such as looking at, vocalizing to, and sniffing the kids shortly after birth suggests that these interactions are vital for establishing a maternal-offspring bond and facilitating early attempts at nursing. Over time, these behaviors decrease but remain significant for up to 24 hours, emphasizing the bond's importance.
Maternal recognition begins hours before birth and concludes with the mother accepting the kids, usually evidenced when the mother allows the first suckling. In sheep, this occurs between 20 and 30 minutes postpartum (Lynch et al., 1992). Contact between mother and offspring is essential for mutual recognition and helps stimulate the kid's behavior, breathing, and thermoregulation (Nowak et al., 2021). This direct interaction notably reduces kid mortality rates, which are a major concern in goat farming, as high mortality negatively impacts production and raises costs (Flinn et al., 2020).
The olfactory and auditory cues used by goats play a critical role in maternal-filial recognition. Cleaning the newborn's body supports olfactory recognition, stimulates breathing, encourages udder-seeking, promotes thermoregulation, and prevents hypothermia (Dwyer and Lawrence, 2005; Porciuncula et al., 2021). This early bonding, supported by physiological and sensory adaptations, is essential for psychological development in ungulates (Lévy, Keller, Poidron, 2009).
A standing posture and low maternal movement are linked to successful nursing. A kid’s attempts to nurse are hindered if the mother spends too much time lying down or moves excessively (Blackshaw, 2003). In terms of the kid’s behavior, recognition of the mother develops in the first week of life, based on visual, olfactory, and auditory signals. These signals elicit maternal care reactions, such as licking the kid to remove birth fluids, reducing heat loss, and encouraging udder exploration and suckling (Dwyer, 2014).
The high frequency of vocalizations observed in goats is influenced by genetic and environmental factors. Less selected and free-range breeds, such as the Azul genetic group, tend to vocalize more than confined or specialized breeds (Dwyer and Lawrence, 2005). Vocalizations help establish maternal-filial bonds, with goats emitting specific sounds during birth to guide their kids (Dwyer et al., 1998; Sèbe et al., 2010; Nowak et al., 2021). These vocalizations also provide calming signals for the offspring, reducing anxiety caused by separation.
Kids who stand and nurse sooner also tend to spend less time on the ground, minimizing contamination risks and improving their balance. The mother's support, through minimal movement and proximity, plays a crucial role in these early behaviors.
The climatological data collected during the behavioral observations (black globe temperature, dew point, relative humidity, wind velocity) provide an important environmental context. Although no direct statistical association was found between climatic variables and maternal or kid behaviors in this study, their inclusion is justified for two reasons:
Environmental influence on behavior: Climatic conditions, particularly thermal stress, can alter grazing, lying, and vocalization patterns in goats. High temperatures and humidity may reduce activity levels and increase lying behavior, while cooler conditions may favor more active maternal care.
Characterization of experimental conditions: Even in the absence of direct correlations, reporting climatological data ensures transparency in the environmental context in which behaviors were recorded. This allows comparisons with other studies conducted under different climatic conditions and supports reproducibility.
Thus, the climatological variables serve both as a control factor and as a contextual descriptor of the study environment. Their inclusion strengthens the methodological rigor, even if no direct behavioral effects were detected.
CONCLUSIONS
In conclusion, the data reinforces that maternal behavior plays a crucial role in the survival and healthy development of kids, especially in the first hours after birth. The interaction between mother and kid, characterized by care such as cleaning, vocalizations, and physical proximity, contributes to the formation of the maternal-child bond, which is essential for successful breastfeeding and for reducing kid mortality.
In addition, factors such as the mother's posture, time spent close to the kid, and olfactory and auditory signals are key to ensuring that the kids receive colostrum efficiently and develop adaptive behaviors. Management strategies that consider support for mothers during the postpartum period and the selection of genetically adapted breeds, such as the Blue genetic group, can improve animal welfare, increase productivity, and reduce costs associated with mortality.
ACKNOWLEDGMENTS
The authors would like to thank CAPES (Coordination for Improvement of Higher-Level Personnel) for financing the project, the Federal University of Campina Grande - Brazil (UFCG), and the CNPq (National Council for Scientific and Technological Development).
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The research data are available upon request.
