AW=proportion of empty body water

AA=proportion of empty body ash

SBW=shrunk body weight, kg

EBW=empty body weight, kg

TA=total ash, kg

2. For CS=1 ash, fat, and protein composition are as follows:

AA1=0.074602

AF1=0.037683

AP1=0.194208

where:

AA1 is proportion of empty body ash @ CS=1

AF1 is proportion of empty body fat @ CS=1

AP1 is proportion of empty body protein @ CS=1

3. Assuming that ash mass does not vary with condition score, EBW and component body mass at condition score 1 is calculated:

EBW1=TA/AA1

TF=AF * EBW

TP=AP * EBW

TF1=EBW1 * AF1

TP1=EBW1 * AP1

where:

EBW1 is Calculated empty body weight at CS=1, kg

TF is total fat, kg

TP is total protein, kg

TF1 is total body fat @ CS=1, kg

TP1 is total body protein @ CS=1, kg

4. Mobilizable energy and protein are computed:

FM=(TF-TF1)

PM=(TP-TP1)

ER=9.4FM+5.7PM

where:

FM is mobilizable fat, kg

PM is mobilizable protein, kg

ER is energy reserves, Mcal

5. EBW, AF and AP are computed for the next CS to compute energy and protein gain or loss to reach the next CS:

EBW=TA/AA

where:

EBW is EBW at the next score

TA is total kg ash at the current score

AA is proportion of ash at the next score

AF, AP, TF and TP are computed as in steps 1 and 3 for the next CS and FM, PM, and ER are computed as the difference between the next and current scores.

Table 3–4 gives CS descriptions and Table 3–5 shows the percentage composition and SBW change associated with each CS computed with this model. This model predicts energy reserves to be a constant 5.82 Mcal/kg liveweight loss, which compares to the 1989 NRC dairy value of 6 Mcal/kg, the CSIRO values of 6.4 for British breeds and 5.5 for European breeds, the INRA value of 6 and the AFRC value of 4.54. Protein loss is predicted to be 81 g/kg, compared to 117, 135, 138, and 160 g/kg weight loss for the Buskirk et al. (1992), CSIRO (1990), AFRC (1993), and NRC (1985) systems. SBW is predicted to be 76.5,

TABLE 3–4 Cow Condition Score

Condition Score

Body Fat, percenta

Appearance of Cowb

1

3.77

Emaciated—Bone structure of shoulder, ribs, back, hooks and pins sharp to touch and easily visible. Little evidence of fat deposits or muscling.

2

7.54

Very thin—Little evidence of fat deposits but some muscling in hindquarters. The spinous processes feel sharp to the touch and are easily seen, with space between them.

3

11.30

Thin—Beginning of fat cover over the loin, back, and foreribs. Backbone still highly visible. Processes of the spine can be identified individually by touch and may still be visible. Spaces between the processes are less pronounced.

4

15.07

Borderline—Foreribs not noticeable; 12th and 13th ribs still noticeable to the eye, particularly in cattle with a big spring of rib and ribs wide apart. The transverse spinous processes can be identified only by palpation (with slight pressure) to feel rounded rather than sharp. Full but straightness of muscling in the hindquarters.

5

18.89

Moderate—12th and 13th ribs not visible to the eye unless animal has been shrunk. The transverse spinous processes can only be felt with firm pressure to feel rounded—not noticeable to the eye. Spaces between processes not visible and only distinguishable with firm pressure. Areas on each side of the tail head are fairly well filled but not mounded.

6

22.61

Good—Ribs fully covered, not noticeable to the eye. Hindquarters plump and full. Noticeable sponginess to covering of foreribs and on each side of the tail head. Firm pressure now required to feel transverse process.

7

26.38

Very good—Ends of the spinous processes can only be felt with very firm pressure. Spaces between processes can barely be distinguished at all. Abundant fat cover on either side of tail head with some patchiness evident.

8

30.15

Fat—Animal taking on a smooth, blocky appearance; bone structure disappearing from sight. Fat cover thick and spongy with patchiness likely.

9

33.91

Very fat—Bone structure not seen or easily felt. Tail head buried in fat. Animal’s mobility may actually be impaired by excess amount of fat.

aBased on the model presented in this chapter.

bAdapted from Herd and Sprott, 1986.



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