Doubled-Muscled Cattle Breeds

Study Notes

Some breeds of cattle, such as Piedmontese, Parthenais, and Belgian Blue, have a deficiency in the myostatin gene, leading to increased muscle mass and higher yields of meat for cattle farmers.
The key benefits of inactivated myostatin in cattle include tender beef with reduced collagen content and lower saturated fat levels.

Analysis of animal databases has identified around 344 quantitative trait loci (QTL) associated with milk traits, which can be used as genetic markers to predict milk volume and quality.
Four key genes associated with milk production and quality are:
- PRL (prolactin): associated with milk production performance
- LEP (leptin): associated with better milk yield, energy balance, and fertility
- DGAT1 (diacylglycerol O-acyltransferase 1): associated with milk yield and composition
- ABCG2 (ATP-binding cassette, subfamily G, member 2): associated with milk yield and composition
Marker-assisted selection can be used to breed animals that produce higher volumes of milk, improving on-farm productivity and enhancing traditional mechanisms for identifying elite animals.
Researchers are also working to identify valuable micro-components in milk (proteins, carbohydrates, peptides, and lipids) and the genes associated with them, which could lead to the development of health-promoting products.

Researchers have used cloning technology to introduce human genes into the DNA of Holstein dairy cows, producing high-protein milk for the cheese industry.
The genetically modified cows produce milk with:
- Up to 20% more β-casein
- Twice the amount of κ-casein compared to conventional cows
This modification allows cheese-makers to produce more cheese from the same volume of milk.
Transgenic cows have also been developed to produce milk with an inactive β-lactoglobulin milk protein, resulting in hypoallergenic milk.

Breeding programs are being developed to investigate the inheritance of worm resistance, with the long-term goal of breeding sheep that are resistant to worms.
Researchers are working to identify the gene responsible for black and badgerface patterns as well as random spotting on Merino sheep.
Marker-assisted breeding is being used to bring fine wool genes into meat Merinos.

Genetically modified vaccines have been developed to protect cattle from Bovine herpes virus (BoHV-1) and Bovine viral diarrhea virus (BVDV).
A recombinant vaccine, TickGARD, has been developed to protect against anaplasmosis, a disease transmitted by cattle ticks.
A GM vaccine, PneumoStar, has been produced in Canada to combat shipping fever, a complex form of pneumonia in cattle.

Tomatoes with extended shelf-life and delayed fruit softening have been developed using genetic modification.
Yellow crookneck squash with resistance to watermelon mosaic virus 2 (WMV2) and zucchini yellow mosaic virus (ZYMV) has been developed.
Potatoes with less bruising and fewer black spots, enhanced cold-storage capacity, and a lower amount of a potentially carcinogenic chemical have been developed.
Genetic engineering is being used to develop potatoes with more starch and less water, which could lead to healthier french fries or potato chips.
Researchers are working to develop more nutritious fruits and vegetables through a process called biofortification, which involves improving the nutritional quality of food crops through agronomic practices, conventional plant breeding, or modern biotechnology.