Crude protein (CP) is a required nutrient for dairy cattle, typically ranging from 15 to 18% on a dry matter basis. Dietary CP is often the most expensive macronutrient, and there’s been considerable interest in reducing the inclusion rate of high protein ingredients to decrease costs. In addition, there’s greater focus on reducing the...
As long the amino acid profile of the diets, particularly lysine and methionine which are the two major limiting amino acids in the diet, is balanced and a readily fermentable carbohydrate source is included, low CP diets
can be adequately utilised to maintain high milk production. Also, the fibre fractions particularly NDF should be also kept at a low level for effective degradation, digestion and utilisation of the diets. Though milk production of high yielding cows is low in the tropics compared to what obtained in the temperate regions obviously due to environmental factors, the CP content of the diets is slightly lower than 14% with reasonable milk production. It is, however, important that the calorie protein ratio is balanced.
It is not the first time that has been suggested that daity cows can do well with lower crude proteim in the ration, however, 14% CP during early lactation period is not a realistic number, when considered that cows must recover muscle tissue lost pospartum, so stage of lactation would be a very important period to consider.
I have not read Dr.Fredin whole paper to really make a good grasp of his research, but yes, I believe that if the ration is properly well balanced, enough microbial protein might be produced by the rumen to be utilised in the lower gut.
Umberto Francesa, DVM
Would be interesting to see the INRA (Institute Nationale de Recherches Agronomique ) research about the maximun protein movilization permits without consecuences in early lactation cows and the PDI system .
The NRC protein requirements is Always higher than INRA Requirements.
The level of crude protein for milking cows could not be the same in all climatic regions, breed, feed ingredients ( fodder crops or concentrate ) and management are the factors that might be affect the level, in most of tropical and sub tropical condition, the feed are not the same as temperate regions, the digestibility seems to be lower, that why adding slightly more than 18 %.
thanks .
Dr. Abdul Qader Samsor, DVM. animal production dip
Some interesting comments, for me rumen function optimisation is key priority number 1, cud rates, rumen fill, manure score, milk yield, solids, etc but then 'if' opportunity presents to reduce CP by ensuring quality protein requirements are met then it's a 'look see' and ask the cows!
In my opinion, lactating dairy cows don't have a specific requirement for crude protein. Crude protein is only a measure of the nitrogen content of available feedstuffs, and does little to realize the vast differences in MP coming from the growth of bacterial protein.
In a very broad term, diets that are high in fermentable carbohydrates (ie; corn silage) will present the opportunity to support higher levels of milk production at lower diet crude protein levels (ie; 14%). Contrast this with a diet lower in carbs and very high in soluble N, and you should see a diet with lower bacterial protein yield, higher urea cost and ultimately a higher dietary crude protein to support the same milk.
When talking about how low we can go with the protein of these diets, we are really discussing how we can maximize microbial yield.
In Colombia, all cows are in pastures with 21% protein, the energy from sugars and pectins works very good maintain the yield, and better protein in milk, reducing until 10 of Mun, with only 7% of protein
This has been touched on, but you need to do two things to maximize performance with lower protein diets:
1. Feed a high-quality mixed (alfalfa and grass) forage with high NDFD to stimulate microbial protein production in the rumen. 2. Feed a high-quality protein source with both adequate by-pass protein at the rumen, and highly-digestible by-pass protein in the small intestine.
For example, see the third paragraph and graph with information on quality rumen by-pass:
Results of our recent study suggest that total digestibility and microbial N sequestration from starches was maximized with extensive grain processing, and that requirement for RDP was met at low dietary RDP compared to recommended NRC value. In this study, response of cows fed intensive maize processing + low RDP was comparable to coarse maize + NRC RDP suggesting that.
In my opinion when we use low protein with high starch (more than 25%) diets in dairy cows,we give opportunity for increasing MP. Then if we supply MP, milk production also will increase. I had the same as experience.
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