Category: Feedout

Question:

"I have a case with a herd in acidosis. Cows are feeling really bad, no rumination , milk production is decreasing and a lot of variation on the milk shipping. Here's the case :

  • It's a ration with 30kg of BMR corn silage
  • When we took the pH in the bunker it was at 2.8
  • It is a 2010 corn silage bunk
  • There's 52% of grain in this silage
  • Strangely the bunk started to flow 11 months after the bunk was packed and cover
  • In my opinion, the silage management is great
  • The bunk was treated with Biotal Buchneri 500

What do you think happened to get a pH that low?

Does it have an impact on the ration ? (reducing the rumen ph)

Is there a problem with the fiber in BMR corn?

I think that the ration the producer is feeding needs more effective fiber. We use corn silage to bring fiber and energy in the ration. Is it possible that BMR corn silage doesn't bring enough fiber?

The producer and the feedman are satisfied with efficay of Biotal Buchneri 500.

They beleive BMR is the source of the problem.

They're considering not feeding BMR corn silage anymore but the producer must utilize his feed inventory.

 

Answer:

 

  • The pH 2.8 is very low (in fact I've never seen one below 3.3-3.4, especially at 35 %MS), but I'd rather to use the pH from the lab report (3.57); it is on the low end of the usual range however I personally use total concentration of acids as red flag (higher than 10% may result in intake depression)
  • The other parameters on the report seemed OK, potassium a bit low (the ration formulation/analysis will be imperative to address the issues properly) and the NDF-D on the high end of the BMR range. Thus, the fermentation characteristics look OK
  • The BMR should reduce the need for grain and the amount of silage fed should provide enough fiber; however, how is the chop length of the silage and ration? The particle size looks short in the photo that you sent. Do you have a particle size separator to evaluate that?
  • Since there is suspicion of acidosis, have you noticed some more indicators of it, e.g., animals with sore feet, variations specifically in milk fat tests, diarrhea…?
  • You have told us this is a 2010 corn silage, (long storage time for in silo hydrolysis, [the silo leaked some after longer term storage], & proteolysis). The soluble protein of 52% tells us this is a cooked out corn silage. This is significant for the points I will refer to below. I would keep taking regular monthly analyses of this silage so there are no surprises. I personally would wonder how well NIR reflects this type of corn silage, and would be inclined to do some wet chemistry analysis from time to time as well as NIR.
  • The actual ADF, NDF are not remarkable for this type of crop and it's not accurately reflected in this type of analysis any way. Its key is in better digestibility & rate values. What we do now about this BMR corn silage sample is an NDF-d 30 of 69.3 is high, (we do not have a rate value from this lab but we can assume the kd is >5.0; again high). Relevant to the NDF-d is the low lignin, (0.87%). BMR by definition is a low lignin corn silage crop, (1.1-1.5% usually), but this sample is unusually low. This is a rumen fragile, highly digestible, high rate of passage sample of BMR corn silage.
  • The starch analysis is not on the high side, (but does tie in with your grain calculation). Historically starch in BMR corn silage is of relatively low digestibility, but like all corn silages this changes over time. (Some labs in the USA measure for this now). I think we can assume after long term storage the starch in this sample is fermentable. The question in my mind is: how much kernel processing has gone on? If this corn silage is well processed then it's a challenge to the cows' rumens, (SARA). If its partially processed some could get in the hind gut & HBS is a risk, (rate of passage remember!). Is any one seeing any corn kernels in the milk cow manure, or the pre-fresh dry cows if they are fed it, -a really big clue!!
  • Note the sugar, (6.27%), that's high if it's a true value, (NIR versus wet chem.!!). This sample of BMR corn silage is well fermented out anyway, and if that residual sugar value is true that's more residual carbohydrate to challenge the cows rumen.

I am not trying to paint a black picture of BMR, it's a crop I like, I always recommend it and can work with it to make dairy farmers money. This sample is highly digestible and fragile and will not behave like a true forage. In effect,t it is not a source of physically effective NDF. It will need special consideration in the ration to make sure it works well, (straw, stemmy hay, whole cottonseed) from a rumination & rate of passage point of view. Then, balance off the highly digestible carbs in the forage to make sure that side of the ration is covered. After that, good DCAD and Lallemand rumen yeasts and we can turn this herd around.