Boosting metabolise protein in lactating diets

Protein is a key factor in a lactating cow’s diet, crude protein (CP) is the common way to express the level of protein within a diet, this as the name says is very ‘crude’ and is only a measure of the nitrogen without taking account of quality or true protein within the diet.

Supplementing protein can become very expensive, and research shows that only 30% of the nitrogen (protein) we feed ruminants is actually utilised by the cow and converted in to milk or meat (O,Donovan et al, 2013). The rest is lost either in the urine, faeces or as milk ureas, this poses a huge environmental challenge and we need to be proactive in reducing nitrogen secretion and capturing more nitrogen within the rumen. Is there a way we can reduce protein intake but maintain or boost protein output?

A bespoke and flexible feeding programme designed to achieve optimum performance from forage

Over the years CP has been overfed to compensate for feeding poorer quality protein sources, with lactating cow diets being formulated up towards 18% CP. This not only adds a financial
cost to the diet, but also causes health and fertility issues with milk ureas being far higher than they need to be.

Rumen degradable protein (RDP) is broken down in the rumen to ammonia, which is used to create microbial protein by the rumen bugs; the rumen bugs also need sufficient fermentable
carbohydrates (starch and sugar) to feed on. If there is too much ammonia and insufficient energy, ammonia will build up and pass through to the bloodstream. Ammonia is toxic to ruminants, so is converted to a urea in the liver, there is an energy and metabolic cost to doing this which can affect milk yield and fertility. Milk ureas should be targeted at between 180-240mg/L (0.018-0.024).

In UK grass silage fed herds, there should be a good supply of RDP entering the rumen, in the majority of situations the level of fermentable carbohydrates in the rumen is the limiting factor. We need to balance the rumen up correctly to maximise microbial protein yield by adding enough RDP, along with far higher levels of starch and sugar, but making sure we do not create too much of an acid load.

If we can maximise output of microbial protein we can add protected bypass proteins to the diet to fulfil metabolizable protein requirements, at this time we can also add any essential amino acids (EAA) which are limiting within the diet such as methionine.

Compounds to meet MP requirements

Wynnstay have developed compounds to feed in conjunction with a range of diets to fully utilise MP yield to benefit the health of the cow along while realising potential milk yields. By increasing starch and using good quality and bypass protein sources were able to lower CP and achieve higher rumen nitrogen efficiency.

When setting up a diet it is easy to match milk from metabolizable energy (ME) and milk from MP in a base partial mixed ration (PMR), however as adding concentrates into a diet when feeding for yield, poorer quality protein compounds can increase milk from ME but don’t satisfy the requirement of the cow for MP; meaning cows do not achieve the higher yields that we are expecting. Having compounds designed to meet MP requirements is key to achieving the potential from your herd.

Superfuel MP

Superfuel MP is designed to be fed along with grass silage or in a PMR when there is no maize silage available. This compound is designed to maximize the supply of glucogenic energy and microbial protein and has a superior EAA balance.
• High starch and bypass protein
• 16% CP
• Glucogenic technology
• Superior EAA balance
• Promoting improved nitrogen utilisation efficiency

HQS Optimiser MP

High Quality Silage (HQS) Optimiser is a compound designed to balance multi-cut silages of high quality. High starch combined with NIS and bypass protein ensures good utilisation of the nutrients gained from making high quality forage.

• Compound designed to balance multi-cut silages of high quality
• High starch, NIS and bypass protein
• 15% CP
• Promoting improved nitrogen utilisation efficiency

Grass Booster MP

Not only in indoor fed herds can benefit from reducing CP intakes; with cows at grass we can reduce total protein, include high quality bypass protein and increase starch, while also buffering the rumen with nutritionally improved straw (NIS). This balance will promote a healthier rumen to increase rumen utilisation of protein and fibre.
• Low protein and very high starch
• Bypass protein
• NIS
• Promoting improved nitrogen utilisation efficiency

Iwan Vaughan
Senior Dairy Technical Specialist
m: 07990 578548
e: iwan.vaughan@wynnstay.co.uk
Twitter: @maesmochnant

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