Know what is in your pit
Silage analysis should be the first step in your feeding plan. Table 1 gives the average composition of first cut silages analysed through the Hillsborough Feeding information System during 2013, to date.
Table 1- Summary of the analysis of 2013 first cut silages analysed by the Hillsborough Feeding Information system
(g DM/kg W0.75)
Of the first cut silages analysed:
- 45 per cent have an intake potential of over 95 units
- 42 per cent have a D-value in excess of 70 per cent
- 55 per cent have an ME content greater than 11 MJ/kg DM
- 71 per cent have dry matters of greater than 25 per cent
While there is considerable variation in the composition of the silages analysed, many farms have excellent quality silage available this winter. If you have not already done so, get your silage analysed so that you know the quality of the silage that you are feeding.
Allocating concentrates to your cows
While concentrates can be allocated to cows using a wide range of strategies, each farm should have a clear protocol for concentrate feeding. Irrespective of how concentrates are offered, the aim should be to maximise the potential of your silage – as indicated by its analysis. One effective strategy by which to minimise the risk of overfeeding concentrates is to adopt a ‘feed-to-yield approach. This approach ensures that the highest yielding cows in early lactation are fed more than lower yielders in late lactation. The approach identifies the expected milk production from silage (M+ figure) and then provides additional supplementation for each kilo of milk produced over the M+ figure (normally at a rate of 0.45 kg of concentrate supplementation/kg milk).
The practical application of this approach is demonstrated in Graph 1, which shows a typical farm scenario involving cows in all stages of lactation, and with varying milk yields.
Graph 1 Average daily milk yield for each cow in the herd, according to stage of lactation
When allocating concentrates within this situation, some basic points should apply if combining a mixer wagon with either in-parlour or out-of-parlour feeding
Firstly, cows should be grouped, according to their daily yield or stage of lactation, into a ‘high’ and ‘low’ yielding group (greater than and less than 28 kilos milk/cow/day on this farm).
The mixes for these two groups should then be prepared so that the amount of blend in the mixed ration is sufficient to meet the requirements of the lowest yielding cows within each of these groups (28 kilos and 10 kilos of milk for the high and low yielding groups, respectively). If the silage is of sufficiently high quality, the lowest yielding cow group may not always require a blend to be added to the wagon mix.
For cows with higher yields in each group, additional concentrates will be required. In the high yield group, cows yielding more than 28 kilos of milk should then be topped up in the milking parlour or using an out-of-parlour feeder. In the low yield group, cows yielding more than 10 kilos of milk should also be topped up. A feed rate of 0.45 kilos of concentrate per kilo of additional milk is satisfactory.
Using this approach, 9 kg of parlour feed can account for an additional 20 kilos of milk above the group M+. Thus cows in the high group with yields approaching 50 kilos can thus be fed adequately. Similarly, offering 9 kg of parlour feed or out-of parlour feed to a cow in the low yield group will allow cows with yields approaching 30 kilos to be catered for.
Cows should be moved between groups as their yield declines. Use milk meters or milk recording to make informed decisions. In this example, it should be farm policy to move cows that are no longer producing 28 kilos of milk from the high yield group to the low yield group. This approach ensures that cows are unlikely to be overfed concentrates, and that more efficient use is made of the forage component of the diet.
Contact your local CAFRE Development Adviser for further information on practical feed efficiency this winter.
Pictured: Michael Garvey, CAFRE Armagh has urged dairy farmers to get the most out of the good silages that they have made for this winter
By Michael Garvey, College of Agriculture, Food and Rural Enterprise, Armagh