Some preliminary observations on the histological development of the fore-stomachs of the lamb I. Histological changes due to age in the period from 46 days of foetal life to 77 days of post-natal life

Abstract

1. A general survey of the histological changes of the fore-stomachs of the lambs from 46 days of foetal life to 77 days of post-natal life is presented.2. In all the rumen foetal specimens the mucosal surface was smooth. At birth small, conical papillae were visible and from this age onwards these papillae increased rapidly in size and tended to be long and tongue-shaped in appearance. Little change occurred in the appearance of the rumen papillae after 56 days of age.3. The outlines of the reticulum reticular ribs were visible in the 100-day-old foetal specimen. At birth the normal honeycomb-like structure of the reticulum was well developed, but the papillae on and between the reticular ribs were small and had rounded tips. From 20 days of age onwards the reticulum features increased in size and the papillae became pointed in shape.4. At 46 days of foetal life the omasum wall was folded to form developing laminae and by 70 days of foetal life laminae of four orders were present. The main age changes in the appearance of the mucosal surface from this age onward was an increase in the length of the laminae, the formation of small conical papillae on the laminae, and an increase in the inter-laminae spaces.5. All three fore-stomachs showed the same general histological changes with age. The epithelium changed from a stratified cuboidal type in the foetal specimens to a keratinized, stratified, squamous epithelium in the post-natal specimens. The basal layer of the epithelium became folded to form papillae, reticular ribs and laminae, and in the rumen and reticulum further folding of this layer took place to form papillary bodies.

Histomorphometric and Immunohistochemical Study of the Goat Rumen During Prenatal Development

“…There is some agreement regarding the appearance of the stratum corneum, which has been observed in sheep at 81 days (54% gestation; Franco et al, 1992) and in deer at 142 days (45% gestation; Franco et al, 2004a). However, other authors report the appearance of this stratum at a later stage: in goats, it was noted by Molinari and Jorquera (1988) at 104 days (70% gestation), while in sheep it has been observed by Wardrop (1961) and Del Rio Ortega (1973) only at birth. The stratum corneum has been reported shortly before birth in buffalo (Tiwari and Jamdar, 1970;Panchamukhi and Srivastava, 1979) and in cattle (Warner, 1958;Asari et al, 1981;Vivo et al, 1990).…”

Ontogenesis of peptide transport and morphological changes in the ovine gastrointestinal tract

“…The mucosal lineing of the rumen is composed of a keratinized stratified squamous epithelium (Wardrop, 1961a).…”

“…Ruminal papillae begin to develop at 100 d of fetal life and by birth the mucus membrane has folded to form numerous papillae (Wardrop, 1961a). By 56 d, there has been extensive development of the papillae in height, width, and surface area (Wardrop, 1961a;Zitnan et al, 1999).…”

“…The omasum is lined by keratinized stratified squamous epithelium and possesses the same four cell layers as the rumen: stratum basalae, stratum spinosum, stratum granulosum, and stratum corneum (Wardrop, 1961a;Lubis and O'Shea, 1978). There is a thick layer of muscularis mucosae beneath the laminae propria followed by a thin layer of connective tissue and serosa.…”

“…These laminae begin to develop at 46 d of fetal life and are visible by 70 d of fetal life (Wardrop, 1961a). By 20 d postnatal, all orders of laminae are greatly increased in length (Wardrop, 1961a).…”