Culling and Selection

selection

it is the process of deciding which animal will remain in the herd to become parents of the next generation

strong legs, long body, good body conformation

bases of selection: pigs - physical selection

selection

it is the process of deciding which animal will remain in the herd to become parents of the next generation

strong legs, long body, good body conformation

bases of selection: pigs - physical selection

mothering ability, average daily gain, backfat thickness

bases of selection: pigs - performance

ADG, FCE, backfat thickness

selecting boars: selected based on economically important traits

2cm

performance basis: backfat thickness should not exceed _____ at 90kg

800g, 2.5

performance basis: select boars that show an ADG not less than _____g and FCE not more than _____

90kg, 160 days old

performance basis: must be at least ____kg and not more than ____ days old during selection

culling

removal of desirable animals in terms of economically important traits and overall performance

reproductive performance and physical appearance

culling must be based on _______ ________ and ______ ________ of the animals

- difficulty in mounting for no apparent reason

- poor semen quality

- highly temperament, vicious, and difficult to handle

- no longer breed or produce viable semen

culling parameters in boars

do not come into heat after 10 months of age

culling parameters in gilts

- have not been breed for 30 days after weaning the litter

- poor maternal instinct and mothering ability

- failed to wean at least 8 healthy piglets

- poor performance in terms of litter size for 2 consecutive farrowinggs

culling parameters in sows

- found positive on infectious diseases like brucellosis, leptospirosis, and pseudorabies

- unsound characteristics (hernia, inverted/blind teats)

culling parameters in boar and sows

- animals own phenotypic merit

- pedigree information and collateral relatives

- progeny tests

in cattle selection: for a single trait selection, selection may be done based on:

13 years

beef cows remain productive for ___ years if they start calving at three years of age

rectangular frame

an ideal beef cow has a ______ frame

well developed digestive system and healthy vital organs (heart, lungs, liver)

a good middle in bull indicates;

- calves one and a half to two years

- produces a little amount of milk and raise a small calf despite good feeding and management

culling parameters in cows

- do not settle despite 3-4 repeated matings with a proven bull

- do not come into heat in spite of proper age, good size, healthy condition, vigor, and strength

- fail to meet the standards set for the breeding herd

culling parameters in heifers

good: fully developed, bright red, waxy

poor: small, pale, shrunken, dry

difference between good and poor layer: comb, wattle, earlobe

good: spread apart, 2-3 fingers can be placed between them

poor: close together, only 1 finger can be placed

difference between good and poor layer: pubic bone

good: large, moist, oval shape

poor: small, dry, round

difference between good and poor layer: vent

good: soft and thin skin, expanded

poor: hard with thick skin, contracted

difference between good and poor layer: abdomen

good: yellow or white after several months of production

poor: yellow even after several months of production

difference between good and poor layer: shank