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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Nutrition and Environmental Management Research » Research » Publications at this Location » Publication #359141

Research Project: Improve Nutrient Management and Efficiency of Beef Cattle and Swine

Location: Nutrition and Environmental Management Research

Title: Effects of the F94L Limousin associated myostatin gene marker on metabolic index in growing beef heifers

Author
item Hales, Kristin
item Tait Jr, Richard
item Lindholm-Perry, Amanda
item Cushman, Robert - Bob
item Freetly, Harvey
item Brown Brandl, Tami
item Bennett, Gary

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: The U.S. Meat Animal Research Center (USMARC) has a unique population of cattle that contain an allele for the myostatin gene, which influences protein accretion. The heifers used in this study were genotyped for this gene and we used either homozygous wild type heifers, or heifers that had 2 copies of the myostatin gene. Body weight was not different between treatments, but it did differ across day increasing as the heifer’s age increased. Oxygen consumed (as an indicator of metabolic rate) was greater for the wild type heifers than the heifers with the myostatin gene, on all days measured. Heat production decreased as heifer age increased in all heifers irrespective of treatment. Respiratory quotient had a tendency to be greater for heifers with the myostatin gene than wild type heifers. Average daily gain measured across the whole study (121 d) was greater for heifers with the myostatin gene. In conclusion, oxygen consumption and heat production were less for heifers with the myostatin gene, while the respiratory quotient tended to be greater. Therefore, it is likely that cattle with the myostatin gene have lower maintenance energy requirements than cattle without the gene. Thus, genotype, if known, should be considered when assessing energy requirements of beef cattle.

Technical Abstract: The U.S. Meat Animal Research Center (USMARC) has a unique population of cattle (MARC I) that is a composite breed of ¼ Limousin, ¼ Braunvieh, ¼ Charolais, and ¼ Angus-Hereford. In this population, an allele for the myostatin (MSTN) gene (GDF8), which influences protein accretion has been selected and is present. The heifers used in this study were genotyped for the MSTN gene mutation to determine their MSTN genotype as either homozygous normal (CC) for Phenylalanine at amino acid position 94 of MSTN (0 copy; n = 5), or homozygous (AA) for F94L variant in MSTN (2 copy; n = 6). Body weight (BW) was not different between treatments (P =/< 0.33), but it did differ across d (P < 0.01) increasing as heifer age increased. Oxygen consumed in liters per kg of metabolic body weight (MBW) was greater for 0 copy heifers than the heifers with 2 copies of the F94L MSTN variant (P = 0.03), on all d measured. Oxygen consumed (L/kg of MBW) and heat production (megacalories [Mcal] and Mcal/kg of MBW) decreased as heifer age increased in all heifers irrespective of treatment (P < 0.03). Respiratory quotient had a tendency to be greater for heifers with 2 copies than heifers with no copy (P = 0.07). Average daily gain measured across the whole study (121 d) was greater for heifers with 2 copies of the F94L MSTN variant. In conclusion, oxygen consumption and heat production were less for heifers with 2 copies of the F94L MSTN variant, while the respiratory quotient tended to be greater. Therefore, it is likely that cattle with 2 copies of the F94L MSTN substitution have lower maintenance energy requirements than cattle without the MSTN gene. Thus, genotype, if known, should be considered when assessing energy requirements of beef cattle.