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18
Forage & Nutrition
Guide 2018
we are seeing a clearer picture of the supplementary intake
required by these cows. Supplementation needs to continue
up until mid-July to support intake.
The next scenario is looking at the demands of the cow
producing in excess of 35kg and the level of supplementation
that they require. As we can see in Diagram 4, we now need
to supplement these cows all year round, but we might stop
supplementing in May or June under the pretence that there is
loads of grass available. Maybe she can eat 17-18kg of grass
DM to make up some of the shortfall, but not all of it, and this
is when nutritionists get a lot of phonecalls ­because of repeat
breeders, low milk protein or falling milk yield.
Living in Ireland, we also must contend with the weather,
and so, we can't assume that these cows will consume 16kg
of grass every day. This affects growth, ground conditions
and utilisation. Also, in the absence of grass measuring and
budgeting, on a lot of farms, this excess grass in the green
area can lead to reduced sward quality and digestibility. This
not only reduces the intake of energy per kg of DM, but also
the actual intake of these cows. Research has shown that dry
matter intake (DMI) can drop by 0.2-0.35kg for every one per
cent drop in the DM of the grass below 18 per cent. This could
mean that on wet days, intake could drop by 2-3kg of DM.
Further research has shown a 0.6kg drop in DMI for every one
per cent drop in the digestibility of the grass.
So, the main points we should consider over the next few
months include:
»
Maximise the growth, intake and utilisation of grass on
the farm;
»
Examine the type of cow you have on your farm and the
range in production;
»
Use the Economic Breeding Index (EBI) reports to see
what type of cow you are breeding on your farm;
»
Base supplementation levels on the type of cow you have
and their current yield;
»
Use the following table as a guide to concentrate
supplementation (silage 65 DM digestibility). This is an
upper feeding limit, so when out full-time on grass at
23L, they might need no concentrate in the summer. But
use forage once you need to go past 2.5kg (23 x 0.11).
0.33kg concentrate/kg of milk
in full-time
0.22kg concentrate/kg of milk
out by day
0.11kg concentrate/kg of milk
out full-time
High-quality silage is important to use as a buffer feed to
avoid the overfeeding of concentrates when grass doesn't
meet requirements above the recommended concentrate
feeding levels (above).
Base cessation of buffer feeding or supplementation on the
requirements of your cows, taking account of the top 20 per
cent of cows, rather than the time of the year.
Make sure buffer feeding is balanced for energy, protein,
fibre and, sometimes underfed in the main growing season,
minerals.
Using a diet feeder can also reduce the waste of feed, which is
sometimes overlooked when you look at manure heaps.
*InTouch, part of Keenan, an Alltech company, can offer feed
formulation, advice and monitoring of production levels via a
smart weigh controller on your diet feeder.
48.0
45.0
42.0
39.0
36.0
33.0
30.0
27.0
24.0
21.0
18.0
15.0
12.0
9.0
6.0
3.0
0.0
Grass gr
o
wth & demand (k
g DM/
c
o
w/
da
y)
Diagram 4: Grass demand of cow based on 35kg or more (600kg plus milk solids [yellow]) as a function of grass grown/cow (green) based
on a maximum intake of 16kg of DM (grey).
305-day lactation
Grass supply/growth/cow
Grass demand/cow
Max grass intake/cow/day
12-Jan
26-Jan
09-F
eb
23-F
eb
09-Mar
23-Mar
06-Apr
20-Apr
04-Ma
y
18-Ma
y
02-Jun
16-Jun
30-Jun
14-Jul
28-Jul
11-A
ug
25-A
ug
06-Oct
20-Oct
03-No
v
08-Sep
22-Sep
17-No
v