The transition from summer grazing to winter housing is often a time when milk production drops temporarily and this can have a knock-on effect on production and fertility throughout the winter. James Ambrose, Phileo Lesaffre Commercial and Technical Manager GB, outlines how to avoid this problem and how to get the best from forage this winter.
Housing dairy cows in the autumn results in a change in environment, social group and diet, and can place cows under significant stress if it isn’t managed carefully. From a nutritional point of view, the change in diet can be dramatic – from a grazing-based diet with supplementary compound feed, and/or a buffer feed, to a full winter ration – and imposes major change on rumen function as the billions of microbes in the rumen have to adapt.
It is worth remembering that the rumen is the engine room of the dairy cow, and it is these rumen microbes that digest and ferment feed, allowing the cow to utilise the energy and microbial protein end products created as a result – which is similar in principal to an anaerobic digester for electricity generation. In effect, when we feed dairy cows we feed these bugs so that they can, in turn, feed the cow – they produce up to 80% of the protein requirements and approximately 70% of the energy requirements. It is, therefore, imperative that we treat them with respect when we formulate and feed diets to herds and, in particular, when we manage feed changes, as rapid changes decrease the efficiency with which the rumen operates.
Change to new diets gradually over 2-3 weeks...
During the dietary changes experienced during housing, the rumen microbes have to adjust and this can take up to three weeks for the bugs to sufficiently change in population size and activity to adequately digest the new diet. Herds are at risk of developing digestive upsets such as rumen acidosis leading to poor rumen function, reduced intakes, lower milk solids yield and, potentially, lower conception rates where this transition takes place too rapidly. Ideally, herds should be transitioned on to the indoor diet over a 2- 3 week period – out by day grazing and in by night for two weeks. What is critical is that this period of diet change is planned – it’s not simply a case of housing cows once the weather turns nasty.
Consistency is king...
Now is a good time to get your mixer wagon serviced and get the blades checked, adjusted and replaced if necessary. Then check whether the mix consistency remains the same right throughout the mix by comparing the ration fed out at the start and end of unloading.
In addition, have your mixer wagon weigh cells calibrated to ensure that you are actually feeding the ration you think you are. The aim is to feed the same diet where possible day in, day out.
It is important to avoid overloading the mixer wagon and don’t over mix/chop the ration – it can cause nutritional problems and also wastes fuel. Aim for a mixed ration of around 45% dry matter, with forages chopped to around 2.5 - 10cm (muzzle width) to minimise sorting and maximise intakes. It is also important to load the mixer wagon in the correct order, starting with forages.
Try to minimise changes to the diet through the winter – agreeing raw material contracts for the whole of the winter period can help with this as it avoids the need for ration changes due to feed stocks running out.
Monitor cows carefully...
Do everything in your power to promote good intakes. Aim for a stocking rate in cubicles of around 85% and ensure that at least 9cm linear per cow of water trough space is available, and that troughs are kept clean. Trough size and water flow rates are also critical factors, as milk is composed of 87% water.
Ensure buildings are well ventilated and lighting is adequate both in terms of brightness and duration.
Feed space should be at least 60cm per cow and watch for neck rubbing to establish whether the head rail position is limiting intake. It may need to be up to as much as 75 cm for cows immediately pre- and post-calving.
Also check for rumen fill (look at the triangular area on the left hand side of the cow under the hook bone) and monitor dung consistency and fibre digestion, as well as the quantity of whole grains in the dung.
Know what you are feeding...
It sounds obvious but it is impossible to effectively ration cows if you don’t know the nutritional value of the feeds you have available to you. Get forages analysed and take new samples for analysis as the winter progresses.
Grass silage is the predominant forage in UK dairy systems and the performance of this year’s first cuts will play a big bearing on the profitability of many producers through the winter, particularly with rising compound feed prices being driven by higher protein prices this autumn.
On average UK 2016 first cut silage samples show:
- Higher dry matter than last year, with slightly higher crude protein content.
- Average ME levels are down and there are fewer high ME (>11.5 MJ ME/KG DM) samples about.
- A 3% increase in NDF levels – reflective of the longer growing season and cold spring – more fibre for the rumen bugs to digest
- Fibre is more digestible and lower levels of rapidly fermentable sugars means samples should provide good rumen health
- Higher pH and lower lactic acid levels
(Source: Trouw Nutrition)
Of course, there is a massive range in silage results, and every farm is different, so it is critical that you analyse your own forage.
But, based on average results, it points to 2016 silages being better than 2015 silages for milk butterfat and rumen pH and health due to a slower digestion and fermentation and less acid- loading in the rumen.
This year’s silage will, however, require more digestion by rumen microbes to fully digest it and unleash the energy stored in the structural cell walls of the silage. What this means is that we need to focus on maximising digestion of these silages to produce more milk from forage.
It will also be important to look at the choice of cereal to be included in compounds and blends to match up the degradation rate of the starch contained within the cereal to the silage, based on its fibre content (NDF) in the clamp.
How Actisaf can help...
Adding Actisaf live yeast to your ration homogenises and stabilises the beneficial microbial population in the rumen, particularly the fibre-digesting bugs and those that naturally buffer the rumen and create more glucose pre-cursor from lactate acid.
This results in enhanced rumen function and more energy extracted from forage, which will support higher levels of milk production and milk solids yield throughout the winter.
Feeding Actisaf therefore helps to ease the transition between different diets which is inherent with the change to winter rations, minimising potential drops in milk production and potential blips in fertility that can arise as a result of digestive upsets at this time.
What’s particularly pertinent this year, with more fibrous, higher NDF silages being typical, is that peer reviewed research has shown that Actisaf promotes increased NDF digestibility in the rumen by up to 7 per cent compared with using sodium bicarbonate as a buffer, and up to 12 per cent compared to a control diet with no rumen buffers, resulting in more milk from forage, something that is crucial under current milk prices.
Summary
- Ease transition to winter rations over 2-3 weeks;
- Service and calibrate mixer wagon and avoid overloading and over mixing;
- Monitor cows carefully to maximise intake;
- Analyse forages so you know what you have and can balance the ration;
- Work with your nutritionist to source the most cost effective raw materials;
- Formulate compound feeds and blends based on your silage analysis;
- Add Actisaf live yeast to your ration to condition rumen bugs for optimal performance during diet transition and ensure that higher NDF forages (more fibrous forages) are more thoroughly digested.