ANSC lactation
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- When do cows have more fat in their milk? Why?
- They have higher fat in winter vs. summer because they are eating hay in winter vs. grazing
- Does the % fat in milk increase during lactation? How much could it go up?
- yep! goes up ~0.5%
- When during milking is there more fat in the milk? What is the % difference?
- in the hindmilk. There is about a 0.2% change
- Who has higher milk fat -- heifers or cows?
- heifers because they produce less milk
- When does the greatest variation in milk composition occur?
- right after calving
-
Colostrum: What is it?
How long is the transition period?
How many milkings till milk is good again? -
- milk present in udder at birth
- ~ 3 day transition
-not savable until after 6 milkings - What is in colostrum?
-
antibodies
vitamins A and D
fat
protein
most minerals - Why is colostrum important? What does colostrum have that makes it so important?
- newborn doesn't have immune system. Colostrum has immune globulins that is essential to the newborn so it lives
- How many glands and teats does a cow have?
- 4 and 4
- How many glands and teats does a horse have?
- 4 and 2
- How many glands and teats do sheep and goats have?
- 2 and 2
- What animals are multiparous?
- sow, bitch
- What do the milk ducts connect together?
- the alveoli and the gland sistern
- what is the gland sistern?
- a large collection area that connects the milk ducts and teat
- what is the streak canal?
- The canal where milk passes from the teat sistern to the outside of the body
- What is the alveolus?
- the secretory tissue of the mammary glad. It has its own blood supply from which milk constituents are obtained by epithelial cells lining the alveolus
- What is the alveolus lumen?
- The place where milk collects once is it made and waits to be let down into the ducts
- what are myoepitheial cells?
- Cells on the outside of the alveolus. They contract to bring milk from the alveolus to the ducts
- What does estrogen stimulate?
- the duct and sistern
- What does progesterone stimulate?
- alveoli growth
- What is growth hormone responsible for?
- the initiation of lactation
- What occurs so that the myoepithelial cells are contracted?
- the prosterior pitutiary releases oxytocin which stimulates to myoepithlial cells to contract.
- what is periostium?
- the covering of a bone
- Where on the body is the best way to indicate mature size
- the hips!
- Do all animals go through the same growth curve?
- yep!
- Who gains faster: LF or SM animals?
- large frame
- Who need more nutrients? (LF or SM)
- large frame
- When fed to a constant weight, who will gain faster and have a better F/G?
- large frame
- When fed to a constant carcass composition, LF cattle usually: (3 things)
-
-are less efficient
-slight advantage in ADG
-not any adv. in days on feed - Do you want to feed to a body composition or a fixed weight?
- body composition
- Are the teats, cistern, ducts and glands already on the udder when a female calf is born?
- yep
-
at puberty: female's estrogen stimulates what?
What does progesterone stimulate? -
estrogen = growth of ducts
progesterone = secretory tissues (alveoli) - How many lbs of milk can an avg. udder hold?
- about 50 lbs
- What stimulates oxytocin?
- the prosterior petutitary
- What stimulates prolactin?
- the anterior petutitary
- holstein's % milkfat
- 3.5
- Ayrshire's % milkfat
- 3.9
- Brown Swiss' % milkfat
- 4.0
- Guernsey's % milkfat
- 4.6
- Jersey's % milkfat
- 5.0