Disease characterization in cloned foals in Colombia, the effect of placental pathologies on the success and survival of cloned foalsfrom two different cell lines

Abstract

Cloned foals born in the different cloning programs in the USA, Argentina, and recently in Colombia have experienced several pathological entities during their pregnancy and neonatal period. These entities include abortions, stillbirths, hypoxic-ischemic encephalopathy, large umbilical remanent, and angular deformity on the fore limb. The objectives of this study were to determine whether cloned foals suffer similar diseases and have the same mortality rate as noncloned ones and the differences between cloned foals from two different cell lines (fibroblastic and bone marrow cells) and, to establish whether mares carrying cloned foals from different cell lines have ultrasonographic, paraclinical, and hormonal profile parameters equal to traditional pregnancies and to determine whether there are differences between the cloned foals from the two different cell lines. In the analysis of the continuous variables, significant mean differences were established in the three groups of mares in PCV, hemoglobin, erythrocyte count, MCV, MCH, serum proteins and globulins, and in lymphocyte counts p<0.05. A risk analysis was made for morbidity and mortality associated with the cell origin of the clone and its pregnancy using chi-square sequential tests and logistic regression, and it was considered statistically significant at p< 0.05. A principal component analysis of the paraclinical findings of the mares with the outcome of the foal and the paraclinical parameters of the foals divided by the origin of gestation was performed to evaluate the components of the response variable and their dynamics. Thirty-four pregnancies of clones of fibroblastic origin, 26 of clones of bone marrow origin, and 32 of non-clones were studied. The presentation of placental diseases compatible with placentitis was significantly more frequent (p= 0.026) in mares with cloned foals from fibroblastic cell lines. Neonatal sepsis was determined to be the most frequent disease and was diagnosed more commonly in foals of fibroblastic cell origin—an increase in the risk (OR 37) (p=0.0006). The risk of death was positive and significant with the fibroblast cell line foals (OR: 9.1. P<0.01) compared to the cloned foals of marrow cell origin and non-cloned foals. The risk of death can be predicted in the neonatal period, and some indicators found in this study, such as signs related to placentitis, are associated with increased neonatal mortality and are more frequent in foals of fibroblastic cell origin.