Errr... I'm confused....

[KayJay]

So I've been reading about calving in dairy cattle so I can have a better idea of differences between them and goats..... I'm totally confused because I'm seeing very conflicting advice on what to feed them when they are near to calving. Several sources say to make sure you don't have them on alfalfa when they're near calving because it will contribute to milk fever, and several say the exact opposite, that it will help ward off milk fever.... With my goats I've always made sure they were on alfalfa because I know they need the extra calcium. What gives?

[michiganfarmer]

Ask a local vet.

[matt_man]

Cows will need to mobilize bone calcium in the last few weeks of pregnancy. If they are fed a high calcium ration, all their calcium needs are being met and they will have trouble mobilizing this bone calcium when calving happens and they will go down. Not to say that all animals are at risk for milk fever or it will happen if they are fed a high calcium diet.

Here is a post from another forum that might help:

Research has shown that dry cow diets that provided less than 10 grams/day calcium were most effective at preventing milk fever. It is not impossible to provide less than 10 grams per day of calcium - I checked the calcium levels of a variety of grasses and found that assuming your cow will be eating 30lbs per day of grasses and NOTHING else (grain etc), mature kentucky bluegrass, bromegrass prebloom, greenfeed oats, quackgrass, rye, and crested wheat are the grasses I could come up with that would actually put the calcium in that level.
THat is assuming that there is no benefit whatsoever to putting your cow below the 41 gr per day maintenance and fetal skeletal requirements and that it is either below 10gr or nothing at all - I fear my post made it sound like you either do it all or nothing. I am sure there are many cows that would not benefit with a diet of any more than 10 grams and then there are many cows that would benefit from a calcium reducing diet of less than 41 gr in order to mobilize calcium from bone the last few weeks. The reason this WAS (I will explain the "was" later) thought to be helpful is that if calcium requirements are met through the diet, metabolic processes for mobilizing calcium from bone will not occur. To shorten the post and make it more simple, after calving, there is an instant and large demand for calcium that can't be met with diet particularily due to dry matter intake normally declining near calving. So how the animal responds is by mobilizing calcium from the bones. Why this can be a problem is that if the cow is fulfilling her calcium needs via the diet BEFORE calving, then the mechanisms responsible for calcium mobilization via the bone will not be in place. In other words, a cow that does not mobilize calcium during the dry period will have difficulty doing so after calving. Normally only a day or so is required for calcium mobilization mechanisms to become effective, so underfeeding calcium during the entire dry period is not that essential. So, underfeeding calcium before calving ensures that the metabolic processes required for mobilization of calcium from the bone are in place. In addition, calcium absorption from the small intestine is proportionately higher when calcium intake is lower, so a low- calcium diet will promote more efficient absorption of calcium from the small intestine. Again, the research suggests that you have to feed less than 10 grams per day to make any difference in preventing milk fever.
Now, more recently, the idea of feeding low calcium diets has been discarded as research is implicating high-potassium forages as the cause of milk fever. The alfalfa that we were discarding because of high calcium levels, also has high potassium . Many nutritionists and dairy consultants believe the high potassium was actually the problem and not high calcium.
So while we may be feeding grass hays in the hope that we will lower feed calcium enough, if potassium comes into the picture, then there are other things a person has to watch for with grass hay. Grass hay CAN have lower levels, but you need to check for overfertilizing and excess manure fertilizing as that has been shown to raise potassium levels in soil and hays.
Potassium drops as forage matures, thus the reason mature forages of okay quality are good to feed to dry cows - although mature grasses are slightly higher in calcium.
Confusing yet?
Anionic salts. I think my hesitation in using them is because milk fever is not going to happen to every animal and is actually not that common, but problems due to improperly feeding anionic salts are definitely there and you may end up with a larger problem than simply milk fever. It is a personal choice to decide if the benefits outweigh the risks when it comes to anionic salts One of the problems with post calving dairy cow maintenance is that her nutrient requirements are often higher than she can ingest due to a reduction in dry matter intake right before calving. You do NOT want to do anything that further impedes their dry matter intake (one of the reasons high grain feeding can also be detrimental immediately before and after calving and SARA is also implicated in a reduction in dry matter intake) . Anionic salts are unpalatable to cattle, and field reports indicate some herds have had serious health problems when fed anionic salts. The reasons for this was related to reduced dry matter intake from feeding too much anionic salt. Reductions in dry matter intake at calving time can predispose animals to metabolic disorders such as displaced abomasum, milk fever, and ketosis, so when you restrict it further by improperly feeding anionic salts, there is a high potential for metabolic
disorders and even kidney damage.
There are ways to manage this with feed testing and formulating plans, including monitoring Urine PH (also helps for monitoring for ketosis LOL). If urine pH is greater than 7.0, they suggest anionic salts, and then urine ph is watched to make sure it does not drop less than 5.5 (too much anionic salts). Heifers should NOT receive anionic salts as the potential drop in dry matter intake is of greater concern than benefits (heifers generally have more problems with reduced dry matter intake than cows, so you don't want to do anything that would reduce DMI). Also, heifers have fewer problems with milk fever and hypocalcemia, so anionic salts are probably not beneficial for them.
And when people choose to feed anionic salts, only do so in close up dry cows to hopefully prevent any problems.

[tailwagging]

I was taught at Grahams school that if you give to much in the feed that the body becomes dependent on it coming from the feed and so doesn't retain any and when she gets a great demand for it (freshens) there isn't any stored so she goes down with "milk fever". If not given enough during gestation she also doesn't have extra stored so you can get the same results "milk fever"

It is a fine line between enough and too much.