The energetics of lactation in domestic dogs was investigated. Two breeds were chosen of different masses, Labrador Retrievers (30kg) and Miniature Schnauzers (6kg). Labradors had larger litter sizes and invested more energy relative to adult weight during lactation. This was shown in a number of ways. During peak lactation they had relatively higher metabolised energy intakes, higher energy expenditures, higher ratios of litter metabolic mass to maternal metabolic mass and produced relatively more milk. In addition Labradors utilised body reserves, an investment the Schnauzers didn't make. Schnauzers, however, invested relatively more energy per pup, which was reflected by their relatively larger offspring energy expenditures. Offspring of both breeds increased significantly in mass over the experimental period of peak lactation, although the Labrador pups were significantly leaner and contained less fat in proportion to body mass than the Schnauzer pups. The gradient of the scaling relationship between litter size and body mass across different breeds of dog was significantly steeper and tighter than the interspecific scaling relationship calculated between different species of Canid of similar mass range. This is consistent with the more recent theories on the evolution of life histories, that interspecific allometric variation is an epiphenomenon of intraspecific variation. This suggests that physical constraints associated with size in dogs may limit offspring investment and milk production. The differences in energy investment during lactation between the two breeds might be explained by variations in their ability to sustain high energy expenditures. Central limitations to maximum metabolisable energy intake and energy expenditure might be important in determining reproductive output in the Labradors. Hence milk energy output might be limited by the ability of the alimentary system to acquire nutrients. In contrast, peripheral limitations might limit Schnauzers' ability to allocate energy to offspring. Hence milk production might be limited by mammary output capacity. A three dimensional model relating energy expenditure and fitness to body mass was produced. This advanced a number of predictions. For instance, it is predicted that the observed FMR/RMR ratio would be greater in larger animals. Second, that maximal sustained metabolic rate would be more likely to be limited peripherally in small mammals. Thus maximum energy intake required for single activities, such as lactation or thermoregulation, could represent peripheral limitations in small mammals but central limitations in large mammals.

Thesis (M. P. H.)--University of Hong Kong, 2005. / Also available in print.

Thesis (Ph. D.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Epidemiology and Biostatistics. Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 96-111) Also available in print.

Thesis (Ph.D.)--Drexel University, 2008. / Includes abstract and vita. Includes bibliographical references (leaves 71-79).

Thesis (M.Nurs.)--Washington State University, August 2008. / Includes bibliographical references (p. 36-41).

Diss. (sammanfattning) Göteborg : Univ. , 2008. / Härtill 4 uppsatser.

Thesis (M.P.H.)--University of Hong Kong, 2005.

Resumo: Objetivou-se avaliar a passagem transplacentária e colostral de cobre e seus principais antagonistas (Zn, S, Fe e Mo) por meio de dosagem sérica e no colostro, em cordeiros e ovelhas da raça Bergamácia. Foram utilizados 20 cordeiros provenientes de parto simples e suas respectivas mães da raça Bergamácia mantidas confinadas a partir de 15 dias antes do parto, alimentadas com silagem de sorgo, ração, feno, sal mineral e água ad libitum. Foram realizadas colheitas de sangue das mães, por venopunção jugular, para extração do soro no momento do parto e do colostro através de ordenha manual (30 mL) nos tempos 0, 24, 48 e 72 horas após o parto. Nos cordeiros foi colhido o sangue para obtenção do soro 0, 24, 48 e 72 horas após o nascimento. Também foram avaliados o peso, temperatura retal, volume globular (VG) e proteína plasmática total (PPT) dos cordeiros recém nascidos até 72 horas.Análises dos níveis de molibdênio, zinco, ferro, enxofre e cobre da silagem de sorgo, feno, sal mineral, ração, soro sanguíneo e colostro foram realizadas por espectofotômetro de absorção atômica. Concluiu-se que os cordeiros apresentaram ao nascimento concentrações séricas de Cu, Zn, S, Fe e Mo semelhante aos das ovelhas, evidenciando a existência de passagem transplacentária de minerais. Houve aumento nas concentrações séricas dos minerais (Cu, Zn, Fe, S e Mo) nos cordeiros após a ingestão do colostro. A concentração sérica de zinco e, sérica e colostral de cobre das mães apresentaram correlação positiva significativa com a concentração de cobre sérica dos cordeiros. O valor médio do índice de massa corporal (IMC) das mães 24 horas após o parto foi 118,55 ± 24,21 e dos cordeiros 24 horas após o nascimento foi 39,48 ± 7,67 / Abstract: The objective was to assess the transplacental and colostral copper and its main antagonists (Zn, S, Fe and Mo) by means of serum and colostrum, in lambs and ewes Bergamácia. We used 20 lambs from simple birth and their mothers Bergamasca kept confined from 15 days before calving, fed sorghum silage, feed, hay, mineral and water ad libitum. Blood samples were collected from mothers by venipuncture jugular extraction of serum at delivery and colostrum by milking (30 mL) at 0, 24, 48 and 72 hours after delivery. In lambs the blood was collected to obtain serum 0, 24, 48 and 72 hours after birth. Were also assessed weight, rectal temperature, packed cell volume (PCV) and total plasma protein (TPP) of newborn lambs within 72 hours. Analysis of levels of molybdenum, zinc, iron, sulfur and copper from sorghum silage, hay, mineral salt diet, blood serum and colostrum were performed by atomic absorption spectrophotometer. It was concluded that the lambs at birth had serum concentrations of Cu, Zn, S, Fe and Mo similar to those of sheep, showing the existence of placental transfer of minerals. There was an increase in serum concentrations of minerals (Cu, Zn, Fe, S and Mo) in the lambs after colostrum ingestion. Serum zinc and copper serum and colostrum of mothers had a significant positive correlation with the copper concentration in serum of lambs. The mean body mass index (BMI) of mothers 24 hours after delivery was 118.55 ± 24.21 and lambs 24 hours after birth was 39.48 ± 7.67 / Orientador: Simone Biagio Chiacchio / Coorientador: Raimundo Souza Lopes / Banca: Luis Souza Lima de Souza Reis / Banca: Simone Fernandes / Mestre

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