Perinatal Physiology in Cloned And Normal Calves: Hematologic And Biochemical Profiles

Abstract

Although a majority of clones are born normal and apparently healthy, mortality rates of nearly 30% are described in many reports. Such losses are a major limitation of cloning technology and represent substantial economic investment as well as justifiable animal health and welfare concerns. Prospective, controlled studies are needed to understand fully the causes of neonatal mortality in clones and to develop preventive and therapeutic strategies to minimize losses. We report here the findings of studies on the hematologic and biochemical profiles of cloned and control calves in the immediate 48-h postpartum period. Cloned calves were similar to control calves for a majority of parameters studied including blood gases, concentrations of plasma proteins, minerals and electrolytes, and white blood cell, neutrophil, lymphocyte, and platelet counts. The most notable differences between clones and controls in this study were reduced red- and white-blood cell counts in clones at birth and 1 h of age. As a group, plasma electrolyte concentrations were more variable in clones, and the variability tended to be shifted either higher (sodium, chloride) or lower (potassium, bicarbonate) than in controls. Previously, we noted differences in carbohydrate parameters, the length of time required for clones to make the neonatal adaptation to life ex utero, and morphology of the cloned placenta. Taken together, our findings suggest that cloned calves experience greater difficulty adjusting to life ex utero and that further research is warranted to determine the nature of the relationship between the physiological differences noted here in clones at birth and concomitant abnormal placental morphology.

Effect of calf death loss on cloned cattle herd derived from somatic cell nuclear transfer: Clones with congenital defects would be removed by the death loss

“…2007a) and hematological/biological profiles (Batchelder et al . 2007b) suggested that SCNT cattle within 2 days of birth might have some difficulty adjusting to their ex utero life. These newborns also had aberrant carbohydrate metabolism such as hypoglycemia and hyperfructosemia.…”

Altered DNA methylation associated with an abnormal liver phenotype in a cattle model with a high incidence of perinatal pathologies

“…As well as the constant developmental waste observed after implantation in cloned pregnancies16, the perinatal period is marked by important foetal and neonatal losses171819. Foetal growth peaks towards the end of pregnancy and makes considerable demands on the maternal nutrient supply.…”

Perfil bioquímico de bezerros da raça nelore, originados por meio da técnica de transferência nuclear de célula somática (TNCS) - clonagem

“…Afora isso, desde o início do desenvolvimento da técnica de fertilização "in vitro" de embriões e da clonagem de bovinos e ovinos, foram descritas as Síndromes dos bezerros gigantes (CHAVATTE-PALMER et al, 2006;BATCHELDER et al, 2007). A macrossomia foi relatada em 20,9 % (9/43) dos bezerros, observou que 69,8 % (30/43) apresentaram peso dentro da normalidade e 9,3 % (4/43) apresentaram peso menor do que o esperado para a raça Nelore (MEIRELLES et al, 2010).…”