Selection for Body Weight in Angora Kids and Young Goats

Wednesday, 28th March 2018

 Many production parameters are linked to the ewe body weight.

  • Kid mortality
  • Post weaning growth rates
  • Reproductive and lifetime reproductive rates
  • Fleece weights

 Selection for body weight in Angora’s is therefore an important economic trait

Gretha Snyman collected data from 2000-2009 of kids born in 11 different Angora goat studs. 

 Traits analysed were:

  • Birth weight (BW),
  • Weaning weight (WW) and
  • Body weight at 8, 12 and 16 months of age (W8, W12 and W16).

 Table 1. Description of the final data set on body weight of Angora kids

Trait

Rams

Ewes

Birth weight (kg)

3.06 ± 0.02

2.84 ± 0.02

Weaning weight (kg)

16.41 ± 0.24

15.11 ± 0.18

8-month body weight (kg)

25.39 ± 0.55

17.34 ± 0.30

12-month body weight (kg)

24.02 ± 0.30

19.64 ± 0.29

16-month body weight (kg)

29.15 ± 0.46

22.79 ± 0.45

The reason why it seems as if the ram kids lost body weight from 8 to 12 months of age, is that in those studs where body weight of the ram kids were recorded after 8 months of age, the rams were not supplemented after weaning. 

 Table 2. Genetic parameter estimates for body weight from birth to 16 months of age

Parameter

Birth weight

Weaning weight

8-month body weight

12-month body weight

16-month body weight

h2

0.22 ± 0.02

0.20 ± 0.02

0.12 ± 0.02

0.34 ± 0.04

0.58 ± 0.03

 

 

Table 3. Maternal genetic correlations between birth weight and body weight at different ages

Trait

Weaning weight

8-month body weight

12-month body weight

16-month body weight

Birth weight

0.44 ± 0.04

0.61 ± 0.08

0.64 ± 0.11

0.55 ± 0.19

 

CONCLUSIONS

  • Selection of young replacement ewes takes place at 16 to 18 months of age in the South African Angora goat industry.
  • The high heritability estimated for 16-month body weight indicated that selection for increased body weight at this age should be successful.
  • Furthermore, selection for increased 16-month body weight should also have a positive effect on body weight earlier in life, and could contribute indirectly to improved kid survivability.

 

REFERENCES/Extracted from

GENETIC PARAMETERS FOR BODY WEIGHT OF SOUTH AFRICAN ANGORA KIDS AND YOUNG GOATS

M.A. Snyman

Grootfontein Agricultural Development Institute, Private Bag X529, Middelburg (EC), 5900

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