Reproduction, Fertility and Development Reproduction, Fertility and Development Society
Vertebrate reproductive science and technology


C. A. Batchelder A , M. B. Whitcomb B , M. Bertolini A , J. B. Mason A , S. G. Petkov A , K. A. Hoffert A , L. W. George B and G. B. Anderson A
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- Author Affiliations

A Department of Animal Science, University of California-Davis, CA 95616, USA

B School of Veterinary Medicine, University of California-Davis, CA 95616, USA

Reproduction, Fertility and Development 18(2) 120-120
Published: 14 December 2005


Health problems and mortality rates of cloned calves are major limitations of cloning technology and represent substantial economic losses as well as justifiable animal health and welfare concerns. The objectives of this study were to compare neonatal viability and physiological status of cloned and control calves. Cloned (Holstein, n = 5; Hereford, n = 3) and control (embryo transfer: Holstein, n = 3; Hereford, n = 3) calves were carried in the same group of Hereford × Angus crossbred recipient dams and were delivered by Cesarean section at term (Days 273–280) following induced labor. Additional calves (Holstein, n = 3; Hereford, n = 2) resulting from AI and delivered vaginally by their natural dams (Days 269–279) following spontaneous initiation of parturition were included as normal controls to evaluate the effects of the induction procedure. Physical evaluations and measurements of blood biochemistry (19 parameters), gases and electrolytes (9 parameters), and complete blood counts (18 parameters) were performed within 10 min of birth and at 1, 6, 12, 18, 24, 36, and 48 h after birth. Cloned calves were observed with increased occurrence of flexural limb deformities (4/8 clones, 0/9 controls; P < 0.05) and developmental delays of physical adjustment parameters such as time to suckle and stand (5/8 clones requiring >3 h; P < 0.05). Cloned calves were more variable than, but not different from, controls for most blood parameters measured. Compared with controls, at birth clones exhibited reduced red blood cell counts (6.8 and 8.6 × 109 cells/mL, clones and controls, respectively; P < 0.01), plasma bicarbonate (23.1 vs. 26.2 mmol/L; P < 0.05), and plasma glucose (39.4 vs. 73.6 mg/dL; P < 0.05). Blood urea nitrogen concentrations in clones tended to be elevated beginning 24 h after birth and were significantly greater than those in controls by 48 h (13.4 vs. 7.4 mg/dL; P < 0.01). Echocardiographic measurements at 24 h of age varied between groups (Table 1) and were indicative of circulatory abnormalities likely originating in utero for clones. The results of this study identified the physiological differences between clones and controls at birth and may be useful in the development of clinical-care protocols to maximize the health and survival of cloned calves.

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