Lactation Flashcards
A traditional lactation curve can be described as…
Upside down Nike swoosh
When is a cow’s peak milk production?
50-70 DIM
What is energy corrected milk?
How many calories came out of the udder
T/F: NEB is greatest within the first 1-3 weeks of lactation
True - most believe it would be highest during peak lactation, but she’s in more of a deficit immediately after parturition
What is the largest factor in NEB: amount of milk being produced (calories out) vs dry matter intake (calories in)?
75% intake, 25% milk
How much you eat is a bigger variable than how much you’re producing
What are the basic components of a lactating cow diet?
Dry matter
Protein
Fiber
Ca and P
Trace minerals
What is the preferred measure of fiber?
NDF
Where do we find most of the fiber?
Cell wall
Common source is hay
Where do we find most of the NSCs (non-structural carbohydrates)?
Cell contents
Common source is grain
Why is corn silage kinda cool?
Mixture of grain and fiber
How does fermentation rate differ between fiber and starch/sugar? What about soluble fiber?
- Starch/sugars are rapidly fermented and can lead to acidosis
- Fiber takes longer
- Soluble fiber are fermented somewhat rapidly
For funsies…what are the three VFAs?
Acetate
Propionate
Butyrate
If you want more milk, what do you feed?
Grain
If you want more fat in the milk, what do you feed?
Add fiber
T/F: NDF (Neutral Detergent Fibers) are listed as a nutrient requirement
False - not a “requirement” meaning they won’t die without it, but it should still be prioritized
T/F: Too much ADF (Acid Detergent Fiber) is associated with feeding too much grain and can lead to rumen acidosis
True
What does effective fiber promote?
Promotes cud chewing
______% of resting cows should be chewing their cud
~ 50%
Kinda tells us how happy the rumen is
Why does the cow put so much bicarbonate and P into saliva?
Bicarbonate acts as a ruminal buffer!
Phosphorus acts as a snack for the bugs!
Most feeds contain about 3% fat, what happens when we have too much fat in a diet (>7%)?
Depresses microbial digestion of fiber
Define degradable protein
Proteins that are broken down into ammonia and CHO in the rumen
Define undegradable (bypass) protein
Protein that is not degraded in the rumen and either is utilized in the small intestine or lost in feces
What is the SUPERIOR protein source?
Microbial protein - leaves the rumen in the form of bugs
What is the benefit of adding grain to the diet (lead feeding) during the dry period?
Adapts bugs
Enhances rumen papillae - better absorption!
What is TMR?
Total mixed ration - each bite contains the same balanced nutrients
Advantages and disadvantages of TMR
Adv: balanced ration
Disadvan: some ingredients do not mix well, cows can be good at separating
What’s an advantage of tie stall barns?
Because each cow is given their own space, customized feeding is possible, but this is more labor intensive
What are some basic feed bunk management guidelines?
1 waterer/25-30 cows
Good footing, light, ventilation
2-2.5 feet of bunk/cow
Provide feed for 20-22h/d
Feed at least 2x/day
Push up between feedings
In general, in a Holstein, milk fat should be >_____% and protein should be around ______%
3.5, 3
Protein:Fat inversion indicates not enough fiber in the diet
What is Posilac?
Recombinant bovine somatotropin (rBST) - increases milk production by 6-20%
Unfortunately most major dairy cooperative will not buy milk from rBST cows
What is the general rule about BCS loss in dairy cows?
Cows should not decrease more than 1 condition score from freshening to peak production
What is 1 BCS equivalent to in lbs?
125-175
T/F: The average cow will have the highest BCS during peak lactation
False - peak lactation will actually be the lowest (2.0-3.5)
A cow has a V line from hooks (tuber coxae) to thurl (greater trochanter) to pins (tuber ischiae). What BCS is she?
< or equal to a 3
If the line between the hooks, thurl, and pins makes a U, what BCS is a dairy cow?
3.25
Both sacral and tail heads ligaments are not visible and the line between the hooks, thurl, and pins is flat, what BCS is she?
4
