Cattle

Question 1

family, subfamily and genus

Answer 1

• *family**: bovidae
• *subfamily:** bovinae
• *genus**: bos (true cattle) species

Question 2

important species of the bovine genus

Answer 2

• *bos primigenius - aurochs:** ancestor of domestic cattle, domesticated 8k BC. Extinct in the 17th century, 2n=60(chromosome nr.)
• *bos poephagus - yak:** largest still existing bovine, bison, tallest wild cattle species. 2n=58
• *bison spp.**: 2 existing spp., american and european bison, 2n=60
• *buffalo spp.:** have variable chromosome no. e.g. water buffalo 2n=48

Question 3

interspecies hybrids

Answer 3

american bison x Yak = Yakalo, only females are fertile (haldanes rule, heterogametic sex more likely to be sterile in hybrids)

Question 4

changes of the domesticated cattle

Answer 4

huge changes, the modern domesticated cattle is considered another species!

(modified genotype for production and diff. environments, used to humans - temperement)

Question 5

pBL - bovine placental lactogene

Answer 5

major role in mammogenesis and milk prod.: It modifies the metabolic state of the mother during pregnancy to facilitate the energy supply of the fetus.

Question 6

important in maternal cattle

Answer 6

incr. no. of offspring and good genetic pool of dam.
(single offspring, low reprod. pot., long puberty, long gestatation. continous polyestrus.

Question 7

first breeding and calving

Answer 7

first breeding: around 15 months or when animal has reached 3/4 of adult weight, first calving at 2-3yrs, great variance among breeds!

Question 8

lactation period in dairy cattle

Answer 8

long period is desired - about 300days. followed by dry period for about 2 months needed for udder regeneration and preparation for new lactation (calving)

Question 9

Twinning

Answer 9

maternal beef cattle: free-martinism in twins of diff. sex! low twinning rate, frequent embryonic losses. may be desired in beef cattle production

Question 10

breeding systems

Answer 10

natural - beef production, often allowed to graze over large areas

AI - frozen, predominantly used in dairy, avoid danger of handling a bull

Question 11

terminal crossings

Answer 11

in commercial beef production for rapid and efficient growth for good carcass composition and quality in progeny of terminal cross.

(two (different) breeds of animal that have been crossbred. The female offspring of that cross is then mated with a male (the terminal male) of a third breed, producing the terminal crossbred animal.)

Question 12

two breed cross, backcross, 3 breed cross

Answer 12

• *cross 2 breeds,** progeny for slaughter
• *backcrossing** for consistent product production
• *3 breed cross:** pureblod replacements, F1 produce terminal slaugther animals (a+b=ab, ab+c =abc 25%, 25%, 50%)

Question 13

rotational cross

Answer 13

optimize with hybrid vigour and complementary characteristics. Purebred bulls of 2+ breeds are used in sequential rotation over crossbred cows

a+b=ab, ab+c =abc AI with d, abcd AI with a again.

Question 14

composite/synthetic breed

Answer 14

e.g. Norwegian red! used to incr. fertility! Planned mating scheme is designed to combine the desirable traits of two or more breeds into one “package”. made up of at least two component breeds, designed to retain heterosis in future generations without crossbreeding and maintained as a purebred.

Question 15

breeding value and aggregated breeding value

Answer 15

genetic value(merit) of an induvidual compaired to a population, for a specific trait. aggregated genetic value is for several traits simultaniously

Question 16

what happens to the calf of dairy cows

Answer 16

sell male calf for veal production or breeding depending on quality, while heifers are kept to replace old animals and increase herd size

Question 17

roundhouse cattle house of dairy cows

Answer 17

stress-free, low disease environment: longer lifetime, incr. milk production.

(about 80 cattle sortet into groups of different needs)

Question 18

cattle technology

Answer 18

• *milking robot, automatic (induvidual) feeding systems, pedometer:** attached to collor or leg to monitor health, estrus cycle to incr. reprod. rate (heat tracking)
• *milk meter:** measure milk amount, milk analyser: quality, health problems: ketosis, rumen acidosis etc. herd management software

Question 19

udder disease in dairy cows

Answer 19

Mastitis is a fatal inflammation of the breast tissue that might end in infection which stops production, one of the main diseases affecting dairy cows! (negative energy balance → higher risk of ketosis, which incr. the risk of mastitis.) different controllations of the cow to decr. risk!

(vitamin and mineral deficiency can also affect udder helth, vit E, C , selenium(ROS))

Question 20

dairy trait heritability used to estimate breeding value

Answer 20

• *rel. high heritability, around 0.4:** milk/ fat/ protein yield, fat/protein/lactose percent
• *rel. low heritability, 0.1-0.2:** lifetime milk/fat/protein yield, somatic cell score(mastitis), productive life

Question 21

Udder features

Answer 21

how well attached to abd. wall, udder depth should be above hock, width, cleft, how close the teats are together, and teat length and symmetry.

Question 22

milk fat content of holstein, brown swiss, jersey

Answer 22

fat: around 4%,

• *holstein**: 3-4
• *brown swiss:** 4
• *jersey**: 4-5% - highest!! but low yield

Question 23

procedure before milking

Answer 23

1. wash teats, dry
2. check foremilk for symptoms of mastitis or irregularities
3. pre-dip teats for killing pathogens, allow time for product to work, dry
4. attach cluster unit properly

Question 24

important traits in beef cattle

Answer 24

calving interval, fertility, calving ease, dociliy(easy handling)

Question 25

heritability of the most important traits

Answer 25

low max 0.1: reproduction
moderate to high.: growth rate and gain, milk production (high!), conformation(high), carcass merit(mod. to high)
e.g. for heifers its imp to choose a bull with low birth weight, as it has high heritability.

Question 26

beef operation facilities

Answer 26

variable housing (fence, barn etc.), all should have handling system to allow easy catching of the animals for routine helth checks and procedures

Question 27

beef cattle technologies; vaccines and antibiotics

Answer 27

• *vaccines** against viral and bacterial diseases before exposure e.g. bovine rhinotracheitis
• *antibiotics** low dose in feed or water to incr. growth rate and improve feed efficiency, manipulation of microorganism in the rumen.