THE MERINO VERSUS TERMINAL SIRE FLOCK MODEL

After entering data describing the flock structure (number of age classes, weaning percentages etc ) and a figure for the proportion of ewes to be mated to terminal sires, choose the Calculate button and the service will indicate whether there will be a deficit or surplus of hogget ewes to maintain numbers in the self-replacing Merino flock.

Alternatively, a manager can indicate their production figures and then check the Break even checkbox and click Calculate to find out the number of ewes to allocate to each flock to break even, that is finding the maximum number of ewes to be mated to terminal sires, while just maintaining the self-replacing Merino flock.

Authors:
Andrew Swan and Matthew Kelly
CSIRO Livestock Industries
Locked Bag
Armidale NSW 2365
02 6776 1300

The model can be used directly on this page or you can download a Microsoft Excel version by right clicking here and saving to your computer.

Hints:
Enter data in first column only
Hold cursor over text to see an explanation

Merino versus Terminal Sire Flock Model
Self replacing ewes Enter your details in this column only Size of breeding stock: 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 4900 5000 5100 5200 5300 5400 5500 5600 5700 5800 5900 6000 6100 6200 6300 6400 6500 6600 6700 6800 6900 7000 7100 7200 7300 7400 7500 7600 7700 7800 7900 8000 8100 8200 8300 8400 8500 8600 8700 8800 8900 9000 9100 9200 9300 9400 9500 9600 9700 9800 9900 10000 10100 10200 10300 10400 10500 10600 10700 10800 10900 11000 11100 11200 11300 11400 11500 11600 11700 11800 11900 12000 12100 12200 12300 12400 12500 12600 12700 12800 12900 13000 13100 13200 13300 13400 13500 13600 13700 13800 13900 14000 14100 14200 14300 14400 14500 14600 14700 14800 14900 15000 15100 15200 15300 15400 15500 15600 15700 15800 15900 16000 16100 16200 16300 16400 16500 16600 16700 16800 16900 17000 17100 17200 17300 17400 17500 17600 17700 17800 17900 18000 18100 18200 18300 18400 18500 18600 18700 18800 18900 19000 19100 19200 19300 19400 19500 19600 19700 19800 19900 20000 Age at first lambing: 1 2 Number of lambings: 1 2 3 4 5 6 7 8 9 10 Weaning percentage: 50% 51% 52% 53% 54% 55% 56% 57% 58% 59% 60% 61% 62% 63% 64% 65% 66% 67% 68% 69% 70% 71% 72% 73% 74% 75% 76% 77% 78% 79% 80% 81% 82% 83% 84% 85% 86% 87% 88% 89% 90% 91% 92% 93% 94% 95% 96% 97% 98% 99% 100% 101% 102% 103% 104% 105% 106% 107% 108% 109% 110% 111% 112% 113% 114% 115% 116% 117% 118% 119% 120% Mortality to 1 year: selected0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% 14% 15% Hogget ewe culling %: selected0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20% 21% 22% 23% 24% 25% 26% 27% 28% 29% 30% 31% 32% 33% 34% 35% 36% 37% 38% 39% 40% 41% 42% 43% 44% 45% 46% 47% 48% 49% 50% Annual mortality 1 year to cfa: 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% 14% 15%     Terminal sire matings   Percentage of flock: 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12% 13% 14% 15% 16% 17% 18% 19% 20% 21% 22% 23% 24% 25% 26% 27% 28% 29% 30% 31% 32% 33% 34% 35% 36% 37% 38% 39% 40% 41% 42% 43% 44% 45% 46% 47% 48% 49% 50% 51% 52% 53% 54% 55% 56% 57% 58% 59% 60% 61% 62% 63% 64% 65% 66% 67% 68% 69% 70% 71% 72% 73% 74% 75% 76% 77% 78% 79% 80% 81% 82% 83% 84% 85% 86% 87% 88% 89% 90% 91% 92% 93% 94% 95% 96% 97% 98% 99% 100% Break even Self replacing ewes Weaners: Hoggets: Hoggets after cull: Breeding ewes   2yr: 3yr: TOTAL 0     Sale/purchase ewes Cull hogget ewes: Surplus hogget ewes: Deficit hogget ewes: cfa ewes:     Terminal sire matings Breeding ewes   3yr: TOTAL 0
© Copyright 2004 CSIRO Livestock Industries and Australian Sheep Industry CRC

This model assumes that the percentage of the flock allocated to a terminal sire is done equally across each age group.

Flock managers who wish to allocate ewes to the terminal sire flock on characteristics other than age can be guided by the totals shown for the self-replacing Merino and terminal sire flocks.