title: Relative importance of pre-partum and post-partum factors in the control of milk yield in the guinea-pig.
abstract: Examination of data pertaining to milk yield and litter growth rate of guinea-pigs at peak lactation showed that milk yield increased with increasing number of pups carried by the dam during pregnancy and also with increasing maternal weight. There was a significant linear correlation (P less than 0.05) of mammary gland weight (expressed per unit of maternal body weight) with litter size. Increasing litter size, within 18 h of parturition, from 1 pup to 5 pups did not elicit a response in milk yield. Decreasing litter size from 5 pups to 1 pup reduced milk yield to the level expected of a monotocous dam. Data are presented showing the ability of the guinea-pig pup to survive from birth without access to milk and the inadequacy of milk supply to meet litter requirements when the litter size is more than 2 pups. The mechanisms controlling lactation in the guinea-pig are discussed in relation to data obtained in other species.
mesh_terms: D000818:Animals; D001724:Birth Weight; D001835:Body Weight; D005260:Female; D006168:Guinea Pigs / Q000254:growth & development / Q000502:physiology*; D007774:Lactation; D008098:Litter Size; D008321:Mammary Glands, Animal / Q000033:anatomy & histology; D009929:Organ Size; D049590:Postpartum Period; D011247:Pregnancy; D011270:Pregnancy, Animal