Practical application of the simplified feeding principle

Since 1974 the simplified feeding principle, feeding fixed daily amount of concentrates and forages ad libitum, has been used on 20 pilot farms with approximately 1400 cows. The technical and economical results based on current and regular control and registration of all inputs and outputs have shown benefits of the change from the traditional standard feeding to the simplified feeding principle. This was the case independent of the system of housing (stanchion barn versus loose housing) and the size of herd. The persons, who took care of the cows, were the same both years (Østergaard et al., 1976). The average yield of the 20 herds was raised with 2 kg of butterfat per month to 253 kg of butterfat per cow and year during the first year after change.

The economy was also improved markedly, as the feed efficiency and the culling rate was unchanged. It should be noted that this demonstration lacks adequate treatments for scientific comparison, as only one treatment (feeding principle) has been planned and practised within year and herd.

The different main types of rations recommended for winter- and summerfe-eding of high yielding dairy cows by means of the simplified fesummerfe-eding principle have been published by Østergaard and Neimann-Sørensen (1976).

In the practical application of the simplified feeding principle the optimum fixed daily allowances of grain mix (concentrates), in the individual herd, was found by means of the current prices and figures shown in Table 7.3. The level of the concentrates fed was adjusted to the quantity and quality of the forage, if the latter was below medium quality, additional 1-2 kg of DM was fed, and if over medium, less 1-2 kg of DM was fed (Østergaard, 1976).

If the yield of an individual cow remained on alow level several months after parturition, then the cow was culled. In spite of this practise, the rate of culling was the same after the change to the simplified feeding principle, as it was before (Østergaard et al., 1976).

The reduction of the allowances of concentrates fed was started about 24 weeks after parturition and was made according to:

a. Expected milk yield based on the last milk recordings.

b. Pregnancy, i.e. number of weeks to the next parturition.

c. Condition and necessary gain in late lactation to attain good and equal condition of the cows before drying off.

When practising the simplified feeding principle the risk of incorrect feeding of the individual cow was lowered, the reasons being 1) the same daily amount of concentrates was fed to a great part of the cows within a herd or to all cows within a group, 2) all cows have, even in early lactation, the ability to consume the moderate amount of concentrates during the restricted time in the milking parlour, and 3) random errors (e.g. random falls in yield) in milk recording do not affect the daily concentrate feeding.

The estimation of the optimum level of TDMI under ad libitum conditions should be made on basis of current prices. The price of the marginal food intake should be used. This price depends on two factors, firstly the marginal forage intake for a changed level of grain mix fed, secondly on the prices of forage and grain mix. This dependence is by the relative prices illustrated in Table 7.4, which is calculated on basis of the following equation:

(39) Marginal price per kg of extra DM =

Grain mix price per kg DM + (marg. forage intake (DM) x forage price) 1.0 kg DM of grain mix + marg. forage intake, kg DM

Table 7.4 Marginal price per kg of extra DM-intake by means of grain mix fed in competi-tion with forage fed ad libitum. Relative to grain mix (100)

Marginal price per kg of DM, when marginal forage intake, for a change of 1 kg of DM of Price ratio: grain mix, is

Forage : Grain mix1) -0.3 -0.4 -0.5 -0.6 -0.7 -0.8 The prices per unit are the value in the best alternative use (opportunity costs) or the price at purchase.

In table 7.5 is for different price ratios given the optimum feeding level in kg of TDMI. These various levels of total dry matter should be composed so that each level leads to ad libitum feeding, as the response functions are estimated under ad libitum feeding of the forage included.

Table 7.5 The optimum level of total daily dry matter intake at various price ratios, kg TDMI per cow during weeks 1-24 of lactation

Price ratio:1)

Price ratio, BTG : FCM 5.0

l) The price per kg of marginal input of DM should be used.

The estimation of the optimum feeding level, expressed in terms of net energy, SFU, is calculated in a similar way. The marginal prices per SFU relative to grain mix can for different marginal forage intake also be seen of Table 7.4, as only »kg of DM« should be substituted by SFU.

In Table 7.6 the optimum feeding level in SFU per cow daily is shown for different price ratios.

Table 7.6 The optimum feeding level in net energy at various price ratios, SFU per cow daily during weeks 1-24

Price ratio:1) SFU : FCM

0.7 0.8 0.9 1.0 1.1 1.2

4.0

16.3 16.0 15.7 15.4 15.1 14.8

Price ratio, BTG : FCM 5.0

(16.8) 16.5 16.2 15.9 15.5 15.2

6.0

(17.4) (17.1) (16.7) 16.4 16.0 15.7

x) The price per SFU of the marginal input should be used.

In Fig. 7.1 the simplified feeding principle is shown in schematical form.

Con- cen-trât.

DM Heifers

Fixed level depends on prices, forage-quality etc.

7

depends on yield and condition

Ad lib.

for-age DM

12 24 36

Week of lactation

Voluntary intake depends on the individual cow

46

Fig. 7.1. The simplified feeding principle. Schematically.

The greatest effect of the practical application of the simplified feeding principle superior to other principles tested in the present long term experiment can be expected, if the planning of feeding the cows within herds having very great potential for yield (roughly 7.000 kg of 4% FCM per lactation), includes about additional 1 kg DM of concentrates per cow daily during weeks 1-24 of lactation. But the cows within a herd with low potential for yield (roughly 5.000 kg of 4% FCM per lactation) should be fed less about 1 kg DM of concentrates per cow daily compared to the optimum level estimated by equations based on the data of the present experiment. It should also be noted that it is advantageo-us, if the daily fixed amount of concentrates is adjusted to possible variation in the quality of the ad libitum fed forage. The daily food intake per cow should therefore be controlled regularly.