Muscle Hypertrophy in Cattle

The Parthenais

The Parthenais cattle breed comes from Deux-Sevres Department of western France. Parthenay was an important cattle market town during the Middle Ages. The French herd book was established in 1893. It is one of the oldest in France. During this period, the Cognac vineyards of the region had been ravished by phylloxera. With the vines all dead, farmers turned to cattle and within a few years the region was renowned for the quality of its butter.

Parthenais BullCredit:

In 1979, butter from the region, Beurre (butter) Poitou-Charente, was assigned AOC status. AOC stands for 'Appellation d-origine controlee' or 'controlled designation of origin' and is a certification awarded by the French government to certain French geographical areas for particular products.

The herd book of the Parthenais goes back to 1893. The Parthenais breed, together with the Belgian Blue and Piedmontese breeds, has a condition known as double-muscling. This is also called muscular hypertrophy and is an inherited condition. A mutation in the animal's genetic make-up suppresses myostatin, a protein element which is partially responsible for proper regulation of skeletal muscle mass. Repression of myostatin results in excessive bulking of muscular growth. Muscle fibres increase in number and, to a lesser degree, enlarge.

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The bulking caused by double muscling makes these breeds the incredible hulks of the cattle world. The massive development in the hindquarters also means an increase in the amount of the more valuable cuts of meat. The collagen or connective tissue also changes in composition. This has the effect of making the meat more tender. Fat cells have less volume of fat so there is less marbling and meat is leaner. The fat also has a greater proportion of polyunsaturated fats and less cholesterol.

Some of the disadvantages of double-muscling include slower maturity, difficulties in calving, lower fertility and reduced milk production. These problems are being addressed by breeders. Since 1970, the Parthenais has been bred as a pure beef breed

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Parthenais have golden brown coats. The eyes, muzzle and legs are lighter in colour and the points of the ears, round the eyes, nose, hooves and tail are black. The feet are hard and black.

The horns are crescent-shaped. Bulls weigh up to 2,600 pounds and measure 145cm at the withers. Cows weigh around 700kg and stand about 135cm. The Parthenais is recognised as having the highest beef to bone ratio of all French breeds (77%). Animals carrying the double muscled mutation have bones which are lighter and less dense hence the higher beef to bone ratios.

Double-muscled breeds are gaining favour as terminal sires for beef production. Although breeding purebred to purebred sometimes causes calving problems, these are much less common when breeding to other breeds such as Angus or Hereford.