Size

A stature of 146 to 148 cms is considered optimal for first-lactating heifers, and about 150 cms for mature cows in the Dutch situation. The combination of the following factors contributes to breeding cows of intermediate stature:

1. smaller cows need a lower amount of feedstuffs per kg milk produced, so they produce more efficiently
2. taller cows are able to produce more
3. the udders of taller cows are further from the ground, which improves the workability
4. very tall cows show higher incidences of handling problems in the Dutch free-stall housing systems

In figure 3 the relation between stature and herdlife is given. The relation found is from a research study, in which data of about 500,000 cows were analyzed in order to quantify the relation between conformation traits and herdlife (adjustments were made for herd-year-season effect and production level).

The relation between stature with the culling rate
(adjusted for herd-year-season effect and production level)

Figure 3 indicates that there is an optimum for stature in regard to herdlife. The differences in herdlife are maximally about 5 percent.

Besides the stature, the length and width of the cow are taken into account when scoring size. The rump angle and front end must have the proper dimensions as regards width and length. Narrow cows are scored lower in regard to size. Last but not least, the body depth is evaluated. More body depth leads to a higher score for size.

The maximum scores for size in relation to stature, mentioned in table 1, can only be obtained if the cows width, length and depth meet the desired standards. The maximum score for size of 89 points can be given only to heifers of 146 to 148 cms height on the condition that the criteria for width, length and body depth are met.

Table 1 Maximum score for size in relation to stature (first-lactating heifers)

stature	maximum score
138	78
140	80
142	82
144	84
145	87
146	89
148	89
150	87
152	85
154	83

Dutch Cattle