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The following information should be used as a guide only. Please contact your local PGG Wrightson representative for further support or guidance.

Conversions

1 kg = 2.205 lb
1 lb = 0.4536 kg
1 cwt = 50.8023 kg
1 ton = 1016.05 kg
1 tonne = 1000 kg
1 acre = 0.4047 ha
1 hectare
= 2.4710 ac
1 metre
= 39.37 in.
1 gallon
= 3.785 l
1 litre
= 0.2642 gal

Convert kilogram (kg) to pounds (lb) 

1 kg = 2.2046 lb
5 kg  = 11.023 lb
10 kg  22.046 lb
20 kg  = 44.092 lb
30 kg = 66.139 lb
40 kg = 88.185 lb
50 kg = 110.23 lb
60 kg = 132.25 lb
70 kg = 154.32 lb
80 kg  = 176.37 lb
90 kg = 198.42 lb
100 kg = 220.46 lb
 

Convert millimetres (mm) to inches (in.)

5 mm = 0.20 in.
10 mm = 0.39 in.
25 mm = 0.98 in.
50 mm = 1.97 in.
100 mm = 3.94 in.
150 mm = 5.91 in.
200 mm = 7.87 in.
250 mm = 9.84 in.
300 mm = 11.81 in.
400 mm = 15.75 in.
 

Convert inches (in.) to millimetres (mm)

1 in. = 25.40 mm
5 in. = 127.00 mm
10 in. = 254.00 mm
20 in. = 508.00 mm
30 in. = 762.00 mm
40 in. = 1016.00 mm

1 km = 1000 m
1 m = 100 cm
1 cm = 10 mm
1 mile = 1.6093 km
1 km = 0.62 mile
1 yd = 3 ft
1 ft = 12 in.
1 in. = 25.4 mm

Breeding

Gestation length is the time between conception and parturition (giving birth).
 
Ewe 148-154 days (5 months)
Cow 275-285 days (9 months)
Mare 335-345 days (11 months)
Sow 112-119 days (4 months)
Bitch 63 days (9 weeks)
Deer 232 days (8 months)
Goat 151 days (5 months)

Animal Duration of Oestrum (Heat) Return after Parturition (Giving Birth) Return if not impregnated
Ewe 1-2 days 4-6 months 17-20 days
Cow 1 day *Refer below 18-24 days
Mare 5-7 days 7-10 days 2-3 weeks or more
Sow 2-4 days 5-6 weeks 17-20 days
Bitch 1-3 weeks 5-6 months 5-6 months
Deer 5-12 hours 18 days
Goat 2-3 days 6-7 months 20-22 days

 *The return of heat period after parturition occurs after a very variable interval.

  • Dairy cows: the normal range is 25-60 days, mean 45 days.
  • Beef cattle: the normal range is 50-160 days, with the average of 80 days.

The chance of conception on a heat less than 40 days is only 49%, but it rises to 65% at 60 days.

Feed Requirements

Grazing animals require a minimum amount of feed each day to maintain their body weight (maintenance) and additional feed for growth, milk, wool growth (production).

As liveweight increases, so too does maintenance energy requirement. Energy is measured as megajoules (MJ) of metabolisable energy (ME).

Feed requirements (MJ ME/day) for growing steers and heifers 

Rate of Liveweight Gain (kgLW/day)
LW (kg) 0 0.4 0.6 0.8 1.0
100 18 28 31 35 39
150 24 33 38 42 46
200 30 42 47 52 57
250 35 47 52 58 63
300 40 53 58 63 68
350 45 58 63 68 73
400 49 68 76 84 92
450 54 73 81 89 97
500 58 78 86 94 102

Assumes maintenance = 0.55 MJ ME/kg liveweight

Add Pregnancy Requirement:

  • 6th month pregnancy = 6 MJ ME/day
  • 7th month pregnancy = 12 MJ ME/day
  • 8th month pregnancy = 24 MJ ME/day
  • 9th month pregnancy = 40 MJ ME/day

Feed requirements (MJ ME/day) for milking cows 

Production – (kgMS/cow/day)
LW (kg) 1.0 1.2 1.4 1.6 1.8 2.0
350 117 131 146 160 175 189
400 122 136 151 165 180 194
450 126 140 155 169 184 198
500 131 145 160 174 189 203
550 135 149 164 178 193 207

Assumes maintenance = 0.55 MJ ME/kg liveweight; 1 kgMS requires 72 MJ ME; Feed contains 11.5 MJ ME/kgDM

For walking add:

  • 2.0 MJ ME/km flat
  • 3.0 MJ ME/km rolling
  • 6.0 MJ ME/km hills

Add 22 MJ ME/cow/day for cows to gain 0.5 kgLW/day (about 0.5 cs/month). Subtract 18 MJ ME/cow/day if cows are losing 0.5 kgLW/day.

Feed requirements (MJ ME/day) for dry cows 

Weeks before calving
LW (kg) 12+ 12 8 4 2
350 45 57 66 82 93
400 50 62 73 87 98
450 55 67 76 98 103
500 60 72 81 97 108
550 65 77 86 102 113

Assumes maintenance = 0.55 MJ ME/kg liveweight; 1 kgMS requires 72 MJ ME; Feed contains 11.5 MJ ME/kgDM; Add 65 MJ ME/kg liveweight gain.

For walking:

  • Add 2.0 MJ ME/km flat
  • Add 3.0 MJ ME/km rolling
  • Add 6.0 MJ ME/km hills

Add pregnancy requirement:

  • 12 weeks before calving – 12 MJ ME/day
  • 8 weeks before calving – 21 MJ ME/day
  • 4 weeks before calving – 37 MJ ME/day
  • 2 weeks before calving – 48 MJ ME/day

Dressing Out %

Dressing out percentage is used to accurately estimate carcass weight from on-farm liveweight.

Dressing out percentages are influenced by live weight and condition. The general rule of thumb applies:

   Dressing Out %
Store Cattle 45-48
Grass Finished  50-53
Crop Finished 52-55
Grain Finished 54-58

Dressing out percentage increases with liveweight.

Bulls’ percentage may be marginally lower than steers’ because of heavier hides and leaner carcasses. Heifers’ percentage may be higher at the same liveweight because of increased fatness.

Traditional beef breeds (Angus, Hereford and Shorthorn) dress out heavier than dairy breeds but lower than when crossed with exotic breeds eg Charolais, Simmental etc.

Sources:
Lamb Report/Market Link
MAFTech, BLENHEIM

The formula for estimating Dressing Out Percentage for lambs is:

Dressing %  Hot Carcass Weight
 x  100
    Live weight without fasting   1

Hot carcass weight is calculated: (Liveweight (kg) x 0.473-1.92) x 1.045 and the standard is taken as 43% for a 13.5kg hot carcass.

The table below gives full liveweight, carcass weight and dressing out relationship based on shorn wether lambs from a long wooled breed.
Full Live Weight (kg)  Hot Carcass Weight (kg) Dressing %   Full Live Weight (kg) Hot Carcass Weight (kg) Dressing %
15 5.4  36.1   39 17.3 44.3
16 5.9 36.9   40 17.8 44.4
17 6.4 37.6   41 18.3 44.5
18 6.9 38.3   42 18.8 44.7
19 7.4 38.9   43 19.2 44.8
20 7.9 39.4   44 19.7 44.9
21 8.4 39.9   45 20.2 45.0
22 8.9 40.3 46 20.7 45.1
23 9.4 40.7   47 21.2 45.2
24 9.9 41.1   48 21.7 45.2
25 10.4 41.4   49 22.2 45.3
26 10.8 41.7   50 22.7 45.4
27 11.3 42.0   51 23.2 45.5
28 11.8 42.3   52 23.7 45.6
29 12.3 42.5   53 24.2 45.6
30 12.8 42.7   54 24.7 45.7
31 13.3 43.0   55 25.2 45.8
32 13.8 43.2   56 25.7 45.8
33 14.3 43.3   57 26.2 45.9
34 14.8 43.5   58 26.7 46.0
35 15.3 43.7   59 27.2 46.0
36 15.8 43.9   60 27.7 46.1
37 16.3 44.0   61 28.1 46.1
38 16.8 44.1      
 
Full liveweight is taken to be lambs weighed immediately off pasture.

The changes in Dressing % are indications only of the maximum likely effect of each characteristic. However not all characteristics operate independently. Care is necessary to prevent double counting, eg in dry summers light lambs may be leaner and be carrying full fleeces. 

Fasting time  12 hours No adjustment
  24 hours  minus 0.3 to 0.5%
  48 hours  minus 1.5 to 1.7%
  72 hours minus 3.0 to 3.2%
Breed Down Cross Lambs plus 1.0 to 1.5%
Sex Ewe Lambs plus 0.4 to 1.3%
  Rams/Cryptorchids minus 1%
Birth rank Twins of similar weight minus 0.6 to 1.0%
Wooly Around 1 kg wool pull minus 1%
Wet wool   minus 2%
Fatter carcasses   plus 1%
Very lean carcasses   minus 1%
At or before weaning   plus 2-3%
Very late in the season   minus 1%
High intake   minus 1%
Low intake   plus 1%

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