With the onset of winter rapidly approaching and grass quality decreasing, Wynnstay’s beef and sheep manager, Bryn Hughes, advises farmers to plan ahead for housing cattle over winter.
During winter, grass quality and dry matter content fall below 20%, meaning cattle do not get the nutrients required from grass alone.
Following his advice in season three, episode nine of the Wynnstay Agri-Hub podcast, in this blog, Mr Hughes outlines four factors to consider when housing cattle over winter:
- Understanding silage quality
- Straw supplementation
- Concentrates
- Bedding
1. A guide to understanding silage quality
To assess silage quality and tailor feeding programmes to maximise profit from home grown forage, farmers should:
1. Ask their Wynnstay representative to sample their silage to find out the quality.
Once the quality is known, farmers can work with their nutritionist to calculate how much, if any, supplementary feed is required.
2. The quantity of silage needed to be fed can be known by using the following simple calculation:
DMI x kg of cattle = required silage quantity
Take the dry matter intake (DMI) of cattle over the winter period and multiply by their weight, the answer will be the quantity of silage required.
Supplementing silage with concentrates is specific to not only each herd, but also groups of cattle, as it will depend on set performance targets which can vary greatly between breeds, age of cattle and their stage in being finished.
Nonetheless, it is always better to make contingency plans early in the season, rather than fight for whatever silage is left later near the end of the season.
Understanding silage analysis: digestibility values
Silage analysis is key for revealing the digestibility and nutritional value of silage, but the terminology can often be unclear. The "D value" in the context of silage refers to the digestibility of the forage.
· It is defined as the percentage of digestible organic matter in the dry matter (DM) of the forage.
· The higher the D-value, the better the quality of the silage, as it indicates a higher amount of nutrients available to the livestock.
· Silage with a D-value over 70 is considered ideal, while a value of 60 and below would indicate a poorer quality, typically associated with late-cut silage.
· The D-value is significantly influenced by the maturity of the crop at the time of harvest and is closely related to the metabolisable energy (ME) value of the silage.
2. Supplementing with straw
While straw has lower nutritional values, in some cases, where silage is short but high in quality, or the cattle are too fat, substituting some silage with straw can stretch things out significantly.
If farmers are concerned that there are fewer bales in their stacks, they should not necessarily worry as modern bales are now denser than traditional bales. Whereas traditional bales weighed around 350kg, modern bales weigh close to 600kg.
To know if there are sufficient quantities of forage to see through the winter period, farmers should factor the weight of bales into their ration calculation, rather than focusing solely on the quantity of bales they have.
3. Concentrates
For weaned calves aiming for another season out on grass, a performance goal of 0.75kg daily liveweight gain is desirable and achievable if they are to be fed solely forage.
However, if silage quality is poor, farmers may need to supplement calves with about 2-3kg of concentrates a day to achieve the 0.75kg daily liveweight gain target.
For cattle close to finishing, their demands will be a lot higher. For native breeds such as Aberdeen-Angus or Herefords, a target live weight gain should be set for around a kilogram a day, increasing to 1.2-1.5kg a day for continental breeds.
If you're trying to finish cattle on poor silage, you really need to feed them adlib concentrates with protein levels of 14 to 15%.
4. Bedding
Bedding is important for cattle comfort and health, as negative bacteria can thrive in wet straw, but for calf rearers bedding is especially crucial, specifically for maintaining body temperature.
Warm calves will convert feed for growth, yet if they are cold, they will have to use that energy to keep themselves warm.
Coming into winter means calves will have different lower critical temperature (LCT) requirements as they go over three weeks of age. LCT is the threshold below which calves must use additional energy to maintain their normal body temperature.
For calves less than three weeks, we will be looking at about 10 to 15 degrees, whereas if they are older than three weeks, their tolerance improves to cope with temperatures as low as six degrees.
Albeit straw is a little expensive, preventative measures such as keeping calves well bedded and using bales to keep out any drafts, will save farmers money in the long run, as it will help reduce health issues such as pneumonia and help to improve feed efficiency.
As the beef trade is relatively buoyant, making the effort to ensure optimal winter housing with adequate supplementary nutrition should pay dividends when selling the cattle in the future as stores or for slaughter.
