Test 5.1

Recommendation on scoring conformation defects in cattle

Introduction

In many conformation systems for cattle defects are scored when scoring animals for linear traits and general characteristics. Most of the time defects are used to determine the score for general characteristics.

This chapter describes characteristics of defects for dairy, dual purpose and beef cattle and contains a list of proposed defects which could be used. They are considered to be important for one of the breed types (dairy, dual purpose and/or beef) and could be considered by countries or organizations, that do not score them up to now. If a country or organization has already a list of defects, they could consider to reduce the list according to the ICAR list

Description of defect

Defects are not there to describe the whole variation in the population, but only a problematic trait (e.g. side leak) or a trait with a high enough frequency in the population.

The number of defects scored should be kept as low as possible as more defects means also more labor.

The easiest way to score conformation defects in a digital system is when a cow is scored for a group of the linear traits (frame, dairy strength, mammary system, legs/feet), the classifier is requested by the system if there are any defects within this particular group.

A conformation defect could be scored when it has the following characteristics:-

• heritable
• not rare
• is problematic for functionality
• is clearly described and visible
• should be scored as 0/1/2 (as soon as there is more variation and the frequency in population is considerable, one could/should consider to score this trait as a linear trait (scale 1-9)
• is used to come up with a score for a general characteristic

Defects have no value to be scored when it is not used in determining general characteristics or when it is not used in a genetic evaluation.

The advantages of scoring defects are:

• get overview what the status of a specific defect is in the population
• could be used for determining the score for general characteristics
• could be used to present figures per bull

Disadvantage of scoring defects:

• difficult to harmonize classifiers as definitions are not always clear and for training sessions it is very hard to find a group of cows representing all defects.

Defects can be scored with 0 (not present), 1 (slightly present) or 2 (pronounced defect). More practical is that classifier score defects only when they are present, 1 (slightly present) or 2 (pronounced defect).

Approved standard defects

The list with approved conformation defects is chosen such that they satisfy the characteristics mentioned in 6.2.

Per defect a definition is given and it is indicated in which type of breed the defect can have added value.

Table 2. List of approved conformation defects

Defects		Used in type of breed
		Dairy	Dual purpose	Beef
1	Open shoulder	X	X
2	Weak crops	X
3	Weak back including loin	X
4	Weak Back		X
5	Weak Loin		X
6	Advanced anus	X
7	High tail	X		X
8	Inset tailhead	X
9	Rump roof-shaped		X
10	Open claws	X	X	X
11	Cork screw		X
12	Crampy	X
13	Boggy hock-s	X		X
14	Thurls too far back	X
15	Weak pasterns	X
16	Front toes out		X
17	Rear toes out		X
18	Thin teats	X
19	Teat-s orientation not down	X
20	Webbed teats	X	X
21	Side leak	X	X
22	Extra functional teats	X	X
23	Bulgy fore udder	X
24	Blind quarter	X
25	Front teat spread forward		X
26	Front teat spread out		X
27	Short teats behind		X
28	Oedema udders		X
29	Udder tilt		X
30	Two stage teats		X

Body defects

Open shoulder

A significant gap between the tip of the shoulder and the side of the body. Shoulder blades are not well attached to the body causing a significant gap between shoulder blade and body/ribs.

Figure 1. Open shoulder

Weak crops

The part of the animal behind the shoulder (just below the chine) is a lot narrower than the shoulder.