Growth, Reproduction, and Lactation in Somatic Cell Cloned Cows with Short Telomeres

Abstract

We previously showed that telomere lengths of 10 somatic cell cloned cows were significantly shorter than normal. In this study, we investigated growth, reproduction, and lactation in these animals to determine if shortened telomeres have any effect on these characteristics. Six Holstein and 4 Jersey cloned cows, derived from oviduct cells, were reared under general group feeding. Body weights were recorded from birth to 48 mo of age. A number of reproductive characteristics were screened during the prepubertal, postpubertal, and postpartum periods. After parturition, milk yields were recorded daily and percentages of milk fat, proteins, and solids-not-fat were measured at monthly intervals. These data were used to estimate production of milk components over a 305-d period. Overall, the cloned heifers exceeded standard growth rates for each breed. The cows were inseminated at the first estrus after they reached 450 d of age, and delivered normal calves except for one stillbirth in the Holstein group. They were inseminated at postpartum estrus to provide second and third parturitions and, again, these pregnancies were normal. Gestational periods and birth weights of the calves were both within the normal range. The average total milk yield per cow in Holstein group clones was less than that of the original cow, whereas Jersey group clones showed a higher average milk yield than the original cow. In both groups of cloned cows, inter-individual variation in milk production was relatively large; however, the coefficient of variation was less than 10%. Our results suggest that the cloned cows have normal growth, reproductive, and lactation characteristics, and thus normal productivity, despite having reduced telomere lengths.

Comparison of the Growth Performances of Offspring Produced by a Pair of Cloned Cattle and Their Nuclear Donor Animals

“…The progeny of the cloned bull, which were produced using non-cloned cows, were normal in birth weight and postnatal growth when compared to those produced by conventional reproductive technologies, such as AI. Subsequent reports have similarly described production of apparently normal progeny from matings of cloned cows and non-cloned bulls [7,9]. …”

Relationships of Survival Time, Productivity and Cause of Death with Telomere Lengths of Cows Produced by Somatic Cell Nuclear Transfer

“…Feeding and conventional breeding of the 1H, 1J and 2H groups were managed as previously reported [14]. All SCNT cows were fed in accordance with NRC standards during the experimental period.…”

“…The SCNT cow groups and their sources of donor cells and individual cows are shown in Table 1. The 1H and 1J groups were investigated in our previous report [14]. For the control cows, 47 Holstein cows produced by artificial insemination and born between April 2001 and March 2002 were used.…”

“…The relationship between survival time and telomere length has been controversial [8][9][10][11][12][13]. We previously reported that there are no relationships between telomere length and development and reproductive and lactation characteristics among 2 groups of dairy breed SCNT cows [14]. There have been fewer reports on the relationships between telomere length and productivity.…”

“…In this study, we surveyed the survival time and cause of death in 18 SCNT cows in 4 groups, including 10 cows of 2 groups (6 Holstein and 4 Jersey cows) observed in our previous report [14] and newly cloned Holsteins (3 cows with measurements of telomeres) and Japanese Black cattle (5 cows without measurements of telomeres). The relationships of telomere length with reproductive ability and milk-producing capacity are described.…”