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Table 4 Relative frequencies and additive and multiplicative adjustment factors to correct weaning weights for the interaction of birth-rearing type (TBR) and dam age classa

From: Effects of birth-rearing type on weaning weights in meat sheep are systematically associated with differences in mean performance among flocks

Type of factor TBR Dam age class, years
1 2 3 to 6 >6 Average
Frequency, % 11 5.5 6.9 12.4 2.2 27.0
  22 4.5 16.4 38.9 5.0 64.8
  33 0.1 1.1 6.4 0.6 8.2
  Sum 10.1 24.4 57.7 7.8 100.0
Additive, kg 11 −0.55 −3.26 −4.49 −3.36 −4.76
  22 4.38 1.87 0.00 1.31 0.00
  33 7.77b 5.26 3.39 4.70 3.39
  Average 4.11 1.63 0.00 1.28  
Multiplicative 11 0.98 0.90 0.86 0.88 0.85
  22 1.18 1.07 1.00 1.05 1.00
  33 1.35b 1.22 1.14 1.20 1.14
  Average 1.16 1.06 1.00 1.05  
  1. aFactors were derived from least-squares means for TBR × dam age class subclasses
  2. badjustment factors for this class could not be accurately estimated from the available data due to low subclass frequencies. Thus, additive adjustment factors for yearling dams with TBR = 33 were derived by adding corresponding additive factors for 2-year-old dams to the difference between 1- and 2-year-old ewes that raise twin lambs (e.g., as 5.26 + (4.38 -1.87 = 7.77). Multiplicative adjustment factors for these lambs were derived by multiplying corresponding factors for 2-year-old dams by the ratio of adjustment factors for 1- and 2-year-old ewes that raise twin lambs (e.g., as 1.22 × (1.18 / 1.07) = 1.35)