FEEDING
FOCUS March 2017 • Issue 21
Silage - the complete picture The latest round of silage analysis for the 2016 growing season has now been correlated. This new data provides us with a complete picture of how the quality of the 2016 season’s silages compares to that of 2015, as well as an insight into how silage quality will impact approaches to feeding this year. Grass silage Overall, dry matter content is slightly up on average compared to 2015, along with crude protein, but sugar and energy levels are down; the most significant differences being in the bottom 25% of producers, who in 2016 produced silage with a sugar value of 1.20% DM compared to 3.20% in 2015. Grass silage results: 2015
2016
Average
Bottom 25%
Top 25%
Average
Bottom 25%
Top 25%
Dry Matter (%)
32.2
25.7
37.5
32.3
25.9
37.6
Energy (MJ/KG DM)
11.2
10.7
11.8
10.7
10.1
11.4
Crude Protein (%DM)
13.4
11.1
15.4
13.6
11.5
15.2
Sugar (%DM)
7.1
3.2
10.4
5.8
1.2
9.1
NDF (%DM)
47.5
42.7
51.8
51.6
46.5
56.2
Feed2Milk Values MELK* (‘/kg DM)
988
944
1034
972
913
1030
TDP** (g/kg DM)
53
45
66
55
47
64
RFC*** (g/kg DM)
171
140
212
163
137
188
*MELK = More energy for the lactating cow (milk yield potential) **TDP = True digestible protein ***RFC = Rapid fermentable carbohydrate
Consequently, average MELK (Milk yield potential) values are also slightly depressed, dropping from 988/ kg DM in 2015 to 972/kg in 2016. However, it isn’t all bad news and the low levels of fermentable energy recorded in our results indicate silage will be rumen friendly and the strong average protein levels will help support milk quality. Impact on performance These results are unsurprising considering the challenges that many faced in the 2016 growing season and with low milk yield potential, careful supplementation will be required to get the best from cows. In systems that are heavily reliant on grass silage, supplementation of rations with other feed sources may be required to ensure good levels of milk production and to maintain long term cow health. Producers should target the use of feeds with a high MELK value that provide a source of rapidly fermentable carbohydrates (RFCs) - such as bread, biscuit meal and molasses. SilageManager Inconsistencies in forage analysis are a common source of frustration for dairy producers, with one sample sent to two different laboratories often providing conflicting results. But accurate forage analysis is essential to ensure cows are fed a balanced diet that complements supplies of forage and are provided with the right level of concentrate supplementation to achieve the most cost effective and productive results. Continued...