Dairy Cattle Lab

Question 1

CA and Dairy

Answer 1

• top dairy state in US in terms of annual milk production
• # 1 agricultural commodity in CA is milk

Question 2

Dairy Cattle

Answer 2

• generally purebred
• intensive operation (more confining)
• most commonly bred through artificial insemination (AI)

Question 3

Holstein

Answer 3

• majority of dairy cattle in US
• black/red and white
• 680 kg (1500 lbs)
• 10,791 kg milk (23,791 lbs)
• 3.7% fat, 3.1% protein

Question 4

Jersey

Answer 4

• light gray, mouse, dark fawn colors
• 454 kg weight (1000 lbs)
• 7848 kg milk
• 4.8% fat, 3.6% protein

Question 5

Guernsey

Answer 5

• light red/fawn w/ white
• 499 kg
• 7028 kg milk
• 4.5% fat, 3.4% protein

Question 6

Brown Swiss

Answer 6

• Swiss Alps origin
• originally triple-purpose (milk, meat, draft)
• officially dairy in 1906 in US

Question 7

Milking Shorthorn

Answer 7

• dual-purpose breed
• red and white, or roan
• 567 kg weight
• 6491 kg milk
• 3.6% fat, 3.1% protein

Question 7

Ayrshire

Answer 7

• lighter colored band around muzzle; gray or brown coat
• 635 kg weight
• 8484 kg milk
• 4.1% fat, 3.4% protein

Question 8

Weaned

Answer 8

• 6-8 weeks

Question 9

Bred

Answer 9

• 15 mo

Question 10

First Calf

Answer 10

• 24 mo

Question 11

Milking

Answer 11

• 305 days (10-14 mo)
• highest production 60 days post calving

Question 12

Breeding

Answer 12

• 90-120 days post-calving (3 mo)

Question 13

Dry Off

Answer 13

• 60 days before calf is due

Question 14

Calving

Answer 14

• 280 days after breeding
• 1 year after first calf is born

Question 15

Bull Calves

Answer 15

• sent off for harvesting

Question 16

Cow Production Cycle

Answer 16

• 305 day lactation (when they’re milked)
• 45-60 day dry period
• 1st calf at 2 yrs
• mated at 15 mo
• once she calves, she is open for 45-60 days before rebred
• calves once a year (305d + 60d)

Question 17

Heifer

Answer 17

• young female dairy bovine that has yet to give birth to a calf

Question 18

Bull

Answer 18

• adult uncastrated male

Question 19

Lactating Cow

Answer 19

• cow producing milk, usually for 305 days after birth

Question 20

Calf

Answer 20

• young female dairy bovine before puberty
• young male = bull calf

Question 21

Dry Cow

Answer 21

• cow that is not producing milk
• dry period lasts 45-60 days before calving

Question 22

Fresh Cow

Answer 22

• cow that has recently given birth

Question 23

Springer

Answer 23

• heifer within 2-3 mo of calving
• belly and udder are “springing” into shape

Question 24

Strip Cups

Answer 24

- to check for clinical mastitis - milk goes through screen into cup and clots -- will stay on top of screen if clinical mastitis present

Question 25

CA Mastitis Test (CMT)

Answer 25

- helps detect mastitis before clinical - includes paddle and mastitis test reagent - degree of gel formation indicates leucocyte count of milk

Question 26

Mastitis

Answer 26

- infection within udder, typical due to bacterial infection that enters via teat canal - pathogens: contaminated bedding materials, mud, transfer from infected animals during milking procedures - detect through CMT (somatic cells in milk using reagent) - prevention: housing management, hygiene in milking parlor, culling of cows that are chronically infected

Question 27

Calves

Answer 27

- should be in dry, draft-free housing - must receive colostrum for at least 1 day (preferably 2-3 days) to transfer immunity from dam to calf

Question 28

Scours

Answer 28

- diarrhea in calves - can be deadly - caused by bacteria, viruses, environmental conditions, overfeeding, parasitism - leads to loss of water, sodium, and potassium; dehydration

Question 29

Dairy Cow External, Rumen, and Udder Anatomy

Answer 29

- see lab manual pg. 47

Question 30

Udder

Answer 30

- consists of 4 quarters - suspended by medial suspensory ligament - milk is removed from teats - epithelial cells lining alveoli secrete milk into hollow lumen of each alveolus - groups of alveoli = lobules - groups of lobules = lobes - milk travels from lumen of alveoli to gland cistern, then removed from teat cistern

Question 31

Puberty

Answer 31

- 9-14 mo (heifers) - 10-12 mo (bulls)

Question 32

Estrous Cycle

Answer 32

- 21 days (19-23 days) - polyestrous

Question 33

Estrus

Answer 33

- 2.5-28 hours

Question 34

Signs of Heat

Answer 34

- stands to be mounted, may mount other cows, highly vocal, nervousness, mucus discharge from vulva

Question 35

Gestation

Answer 35

- 281 days avg

Question 36

Nutrition

Answer 36

- roughages and concentrates - primary concern is to provide enough energy to produce large quantity of milk - dry cows fed hay or fresh pasture

Question 37

Feeding Rules of Thumb

Answer 37

- feed a cow 3.5% DM of her body weight - 50% of DM should come from roughage - lactating cattle require 120-160 L of water per day

Question 38

Housing

Answer 38

- housed intensively, though sometimes pastured on the coast - free-stall barns and dry lot corrals where cows are bedded on sand (CA, UCD) - calves in polydome plastic hutches

Question 39

Bloat

Answer 39

- not considered actual disease, but can cause discomfort and death - signs: abnormal swelling on left side - legume pastures, alfalfa, and high-concentrate feeds are more likely to produce bloat - can be relieved by working animal, passing tube down esophagus, or puncturing rumen using trocar

Question 40

Milk Fever

Answer 40

- occurs shortly after calving due to deficiency of calcium brought on by rapid demand for milk production - IV injection of calcium to treat