Embryonic and fetal development of the collared peccary (Pecari tajacu)

Ultrasound evaluation of fetal bone development in the collared (Pecari tajacu) and white‐lipped peccary (Tayassu pecari)

“…In both species, advanced fetuses showed mineralization in all primary ossification centers and most secondary centers of long bones. Their early development of the skeletal system agrees with the observed early development of external morphology and thoracic and abdominal organs in these species (Andrade, Monteiro, El Bizri, et al, 2018; Mayor et al, 2019). Precocial species are characterized by a high fetal growth rate, delivering at term well‐developed neonates with low parental dependence.…”

“…Precocial species are characterized by a high fetal growth rate, delivering at term well‐developed neonates with low parental dependence. Thus, peccary neonates show both a high ability for sensorial processing to receive stimuli from the environment (Andrade, Monteiro, El Bizri, et al, 2018; Mayor et al, 2019) and a well‐developed musculoskeletal system that provides a higher ability for locomotion, which is of paramount importance for foraging and scape predation (Anthwal & Thompson, 2016; Sarko et al, 2011).…”

“…First signs of bone mineralization were observed after 30% GP CP (42 gestation days) and 32% GP WLP (52 gestation days). The first US signs of skeletal mineralization in both peccaries begin after the differentiation of limbs and genitalia, and formation of eyelid buds, and before the formation of the outer ear, fusion of eyelids, and presence of hooves (Andrade, Monteiro, El Bizri, et al, 2018; Mayor et al, 2019). In both species, the first mineralized structure was the skull, allowing cranial biometry to function as early markers of the gestational age.…”

“…The gestational age (GA) of the CP was estimated using the formula 3 √ W = 0.079 ( t –27.6) proposed by Mayor et al (2019), while for the WLP we used the formula 3 √ W = 0.084 ( t –31.8) presented by Andrade, Monteiro, El Bizri, et al (2018), where W is the fetal weight and t the fetal age in days. The relationship of GA with TDL, CRL, and body mass in all conceptuses was established through linear regressions.…”

“…The reproductive output in the wild is 1.7–1.9 and 1.6–1.7 neonates per gestation in the CP and WLP, respectively (Gottdenker & Bodmer, 1998; Mayor et al, 2009). Recent studies have demonstrated a high precociality in the CP (Mayor et al, 2019) and the WLP (Andrade, Monteiro, El Bizri, et al, 2018), with well‐developed external and internal characteristics in newborns. However, there is still a great lack of knowledge on fetal bone development and the role of the musculoskeletal system in the early life history of these species.…”