Dairy Cows

Birth weight

50-110 lbs; varies with sex and breed

Mature weight

female 900-1,600 lbs; male 1,400-3,000 lbs; varies with breed and condition  

Weaning age

Commonly removed from the cow at 1-2 days of age and fed milk replacer or milk for 4-8 weeks

Breeding age

14-19 months

Normal season of birth

year-round (cattle are polyestrous)

Gestation length

280-283 days

Estrous cycle

19-21 days

Duration of estrus

12-18 hours

Calving interval

11-15 months (12 is preferable but 13 is more realistic)

Normal calf crop

70-80% (multiples at birth are uncommon) Names of various sex classes: Calf, Heifer, Cow, Bull, Steer

Intensive housing systems

In these systems, animals are kept in more concentrated housing, fed higher-quality feeds, and have much more labor, technology, and overall attention directed to them 

DHIA (Dairy Herd Improvement Association)

A national association that helps dairy producers create and manage records and data about their cows for use in making management decisions 

Bull

Intact male

Steer

Castrated male

Cow

Mature female that had a calf

Heifer

Young female cow that has not had a calf

***Calf***

Young cow

Milk

The normal secretion of the mammary glands of female mammals

Milk fat

The fat in milk; synonymous with butterfat

Casein

The major protein of milk

Freshen

To give birth to young and initiate milk production (term specific for dairy cows)

Milk letdown

The release of milk into the teat cisterns so it can be milked or suckled

Dry cow

The stage of lactation where milk production is stopped prior to calving. This period typically lasts between 40 and 65 days

Parturient Paresis (milk fever)

metabolic disorder generally occurring within 72 hours of calving; caused by low blood serum calcium level

Parturition

To give birth. Also called calving

Lactation curve

Plot of milk production over the whole lactation period.  Different species tend to have characteristic lactation curves

Pasteurization

Heat treatment process that destroys pathogenic microorganisms in milk

Homogenized

Milk that has had the fat droplets broken into very small particles so that the milk fat stays in suspension in the milk fluids

Lactose

A disaccharide composed of galactose and glucose (milk sugar)

Solids-not-fat

Total milk solids minus fat; it includes proteins, lactose, and minerals

Somatic cell count (SCC)

The total number of cells per milliliter in milk; SCC is composed of leukocytes (white blood cells) that are produced by the cow’s immune system to fight inflammation or infection in the mammary gland

Mastitis

Inflammation of the mammary gland, most often caused by a bacterial infection

Total mixed ration (TMR)

Feeding system in which all the nutrients required by dairy cattle are mixed together before offering it to the animal. It includes forage, grain, protein supplement, vitamins and minerals