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Communication Dans Un Congrès Année : 2015

Differences between cloned and non-cloned cows during first lactation

André Neveu
  • Fonction : Auteur
Denis Laloë
Minh Nguyen
  • Fonction : Auteur
Daniel D. Le Bourhis
  • Fonction : Auteur
Hélène Kiefer
Hélène Jammes

Résumé

High variability in bovine milk production depends both on genetic and environmental factors. Whereas genomic selection has contributed to greatly improve milk production, mechanisms underlying the influence of the environment are mostly unknow. They can be studied using cloned cows (obtained through nuclear transfer), presumed to have identical genomes. Nine Prim’Holstein cloned cows and nine non-cloned cows were produced at similar periods of the year, raised in similar conditions, and inseminated at the age of 18 months. Eight cloned and 7 non-cloned cows delivered. Body condition score at calving was lower (ΔBSC=-0.6) for cloned cows (P=0.03). During the first 200 days in milk (DIM), milk yield varied greatly among animals but was similar between the two groups, whereas milk fat and protein contents varied less in cloned cows (P=0.004 and 0.09). Around 67 DIM, fat, protein and lactose contents (P<0.05) were lower in cloned cows. Mammary biopsies were then collected from a rear quarter of the udder, but only five biopsies in each group contained more than 60% of mammary epithelial tissue. These were from a sub-selection of cows with a milk production that was representative of that observed among the 9 or 8 cows in each group. Relative levels of transcripts involved in casein, fat or lactose syntheses did not differ, when a cow with a high somatic cell count in milk collected from one of the fore udders at 65 DIM was omitted. It is known that renewal of mammary cells is slow during lactation and mammary specific DNA methylation profiles are likely to be maintained by DNMT1. Here, DNMT1 RNA levels were higher (P=0.05) in cloned cows. This variation may be related to modifications of global DNA methylation profiles and may explain the modified milk production in cloned cows.
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Dates et versions

hal-02743511 , version 1 (03-06-2020)

Identifiants

  • HAL Id : hal-02743511 , version 1
  • PRODINRA : 326484

Citer

Mohammed Bagher M. B. Montazer Torbati, Marion Boutinaud, Nicolas Brun, Christophe Richard, Valérie V. Hallé, et al.. Differences between cloned and non-cloned cows during first lactation. 66. Annual Meeting of the European Federation of Animal Science (EAAP), European Federation of Animal Science (EAAP). INT., Aug 2015, Warsaw, Poland. ⟨hal-02743511⟩
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