Mop up Protein at Turnout


Many producers are failing to make the most of protein. Generally, only a third is used for milk production in the diet, the rest leaves the cow as waste. The situation gets worse at turnout, as Dr Simon Richards from Provimi's NuTec division explains.

Recent drops in milk price have made us all focus even more on maximising milk from home grown forage. The success of this will depend on turning as much dietary protein as possible into milk and protein yield. Unfortunately, cows are not very efficient users of protein. Only 33% of the protein fed ends up in the milk. Of the remainder, only 10% is used for body maintenance whereas around 90% is wasted.

The situation at turnout is even worse. We might be looking at a lovely sward of lush, green grass and have worked out a good grazing system, but its efficiency in producing milk and milk protein can be very poor. Conversion of dietary protein to milk production drops to less than 30%, with more waste protein in the system.

This waste protein is converted to ammonia nitrogen and secreted as urea in the blood in order to detoxify the system. The result is high blood and milk urea concentrations. This not only wastes the protein from grass, but wastes energy as well, leaving less available for milk production. High levels of blood and milk urea have detrimental effects on fertility, with lower fertility rates and they also contribute to feet problems.

Another consideration (now very topical) is pollution control and a drive to be more environmentally friendly. Cattle have been identified as large contributors to ammonia pollution: 80% of total nitrogen pollution in the UK comes from agriculture, with 53% of this from cattle. Waste protein in the dairy cow diets add to this.

Turning dietary protein into milk relies on the work of the rumen bugs. Their job is to capture the protein and take it into the small intestine as microbial protein. From here it is digested and turned into milk. If there are too few rumen bugs or they are lacking in energy, they will not make full use of the protein. Likewise, if there is a sudden influx of protein, the system is overloaded and cannot cope so more protein escapes. To work best, the process relies on a steady release of protein and energy.

Grazed grass has higher crude protein contents than other forage and compound feeds - normally between 22% and 30% - compared with grass silage at around 13%. This makes it a valuable source of cheap protein. However, this crude protein is very soluble in the rumen and the downturn in the efficiency of protein use in grazed grass occurs because there is too much protein for the bugs to cope with. Much of it 'escapes' before the microbial bugs attach. Blood and milk urea’s increase and more waste leaves the cow. Through our global research, work on improving rumen efficiency and boosting protein use has been going on for the past 10 years, and with success.

It is possible to include products in the diet that will give a more gradual release of protein in the rumen, allowing more to be used for milk production. For instance, we have developed a product, Amino ProTek, which is a sugar mineral complex and works by specifically binding to the protein and also boosts the energy supply to rumen bugs. The result is that more protein is 'caught' and made available for milk production.

Just as important, is the fact that waste protein is reduced so blood and milk urea’s are lowered. Reducing blood urea has been shown to have a positive effect on fertility and improving the well-being of the cow.

From our trial work, we have seen an increase in protein used for milk production by over 10% when Amino ProTek is included. So if 3kg of protein is eaten per day (as in a typical winter diet), the milk protein yield will be 1.1kg rather than 1.0kg. At grass, with the grazing ration being less efficient, a cow will eat 4.5kg to 5.0kg of protein to yield 1.0kg milk protein, and the benefit of including the additive is even greater because it stops more dietary protein from being wasted.

In trials, the product has been shown to increase milk yields by 2.0kg a day and milk protein by 11 7gl'day. Based on current milk prices, this is a 3:1 return on investment. As spring approaches, it is worth considering products that can boost protein use from grazed grass. It is important that these products have a proven track record in the UK and they must be cost-effective.

The yield response to feeding Amino ProTek was clearly demonstrated by Keith Chesters, farms manager for dairy farmer and farmhouse cheesemaker Joseph Heler and Son in Cheshire. He used it in the butter feed diets throughout the grazing season. “It added in excess of two litres of milk per cow per day,” says Keith. “It was a very cost-effective diet for us.” The 320-cow herd averages 10,000 litres on twice a day milking. All the milk is used for cheese production, so an extra two litres/day of milk made a significant difference.