Influence of the climatic environment and duration of labor on the mother-offspring interaction in Morada Nova sheep

The objective of this study was to confirm the influences of stress from labor and climate on the formation of the mother-offspring bond in Morada Nova sheep in the first 2 h after delivery or at the moment of the first suckling of the newborn. The data were collected from 80 Morada Nova ewes (25 primiparous and 55 multiparous) and their lambs in 2 periods of the year. On the basis of the average length of parturition and the black globe temperature-humidity index (BGTHI) at the time of the birth, the ewes were grouped into 3 classes corresponding to the length of parturition, classified as short (less than 15 min), medium (between 15 and 30 min), or long (more than 30 min). Similarly, the BGTHI at the moment of birth was classified into 1 of 3 ranges: low (less than 65), intermediate (greater than 65 but less than 80), and high (greater than 80). For the characterization of mother-offspring behavior, evaluations were performed in the first 2 h after birth or until the moment of the first suckling of the newborn. Maternal factors such as maternal grooming, facilitating sucking, frequency of low-pitched bleats, and latency to groom were recorded. For the lamb, attempts to seek the udder, the frequency of low-pitched bleats, latency to first reaction, latency to stand, and latency to suckle were recorded. The lambs were slower (P < 0.05) to stand and suckle when they were born in conditions of a BGTHI below 65. The latencies to stand and suckle were greater (P < 0.05) in newborn lambs born during labor that took more than 30 min. For maternal behaviors, activities such as maternal grooming and the facilitation of suckling were greater (P < 0.05) during the time periods with higher bioclimatic index values. Moreover, the dams cleaned or licked (maternal grooming) the newborns for a lower percentage of time (P < 0.05) when the labor lasted longer than 30 min. From the present study, it can be concluded that newborn Morada Nova lambs are slower to stand and suckle when born under BGTHI conditions below 65. Furthermore, prolonged labor harms the mother-offspring bond, especially in terms of the dam's ability to clean (maternal grooming) her lamb's body and facilitate its first suckling.