Genetics Flashcards
What is breed?
a stock of animals within a species having a distinct appearance and typically having been developed by deliberate selection
What traits should producers focus on?
-economically relevant traits
-production system and feed resources
-marketing program
-current herd performance
What are some economically relevant traits?
-calving ease
-weaning weight
-feed requirements for maintenance
-tenderness
What are growth traits?
*birth weight (h^2= .40-.45)
*milk (h^2 = .25)
*weaning weight (.2-.25)
*yearling weight (.3-.35)
*yearling height, mature height and weight
What goes into birth weight?
-genetics of sire and dam
-maternal environment
-nutrition
-weather
-age of dam
Why do cows tend to have bigger cows in the cold?
all their blood goes to the center of their body where the calf is
What goes into weaning weight?
-genetics of sire and dam
-dams milk
-quantity and quality of forage
-age of dam
-age at weaning
-sex
What goes into yearling weight?
-weaning weight
-nutrition post weaning
-sex
What are reproductive traits?
*fertility (h<.10)
*calving difficulty (.12-.20)
*scrotal circumference (.45-.5)
What are carcass traits?
*marbling (.35)
*carcass weight (.40)
*ribeye area (.37)
*fat thickness (.44)
*yield grade (.36)
Other traits?
-soundness
-temperament
-feed efficiency
Breeds in general
-more than 250 worldwide
-more than 80 in US
-only 10-15 breeds make a significant contribution to total number of cattle in US
British Breeds
-originated in British Isles
-generally smaller in size but have increased fleshing and marbling abilities
Continental Breeds
-originated in Europe
-“Exotics”
-known for weight gain and cutability
-large in size, lean, muscular
Bos indicus
“american breeds or synthetic breeds”
-increased heat tolerance
-pest resistant, disease resistant
-tough meat
Black Angus (British)
-most registrations annually
-black color, polled
-calving ease, meat quality
-originated by Aberdeenshire Scotland, imported in 1873
Red Angus (British)
-red, polled
performance breed in 1954 by selecting red animals from black angus
Hereford/Polled Hereford (British)
-red body with with face; horned or polled
-introduced to US in 1817, followed the longhorn in becoming range cattle
-polled developed in 1901 by selection
Shorthorn (British)
-red,white,roan; horned or polled
-US in 1783 from England
What are some other British Breeds?
belted galloway, galloway, Lincoln Red, Red Poll, Scotch highland, Welsh black
Charolais (Continental)
-white color, heavy muscle, horned or polled
-one of oldest breeds in France brought to US after WW1
Simmental (Continental)
-yellow to red and white color or pattern or black
-prominent breed in Switzerland and France
-imported to NA in 1967
-originally selected for dual purpose breed for milk and meat
Limousin (Continental)
golden red color or black, heavy muscled
-from France in 1969