Why would someone want to cull a ewe? Ewes produce lambs, and lambs sell for money. Sheep farmers want to make money from the sheep.
My number one reason to cull a ewe, she does not produce lambs. I have sheep to make money. I loss money when I feed a ewe and there are no lambs to sell from that ewe.
Sometimes a ewe will miss a breeding due to not being fit to produce lambs, such as having just weaned a lamb and her body has not gained in condition to conceive. Old ewes take longer for their body to gain in condition.
Yearling ewes may not be mature enough in their development when I place a ram with them for breeding.
If a large percentage of my ewes are not pregnant, it might not be a problem with the ewes, the problem could be with the ram.
I have experienced all these reason to cull sheep.
Old ewes. It is hard sometimes to cull an old ewe. Perhaps you have had her for several years, she has produced good lambs for you. Her teeth may be starting to disappear, making it harder for her to feed and produce the energy to keep her strong and her lambs growth. Recently I had to cull an old ewe, Old Dorper. This ewe was the first registered ewe I had purchased. She produced twin lambs at every breeding, never missed. Her lambs grew very good. She only produced three ewe lambs during the seven years I owned her. Because of her production record, I kept two of her ewe lambs. But she was starting to loose teeth, and having a hard time maintaining condition on pasture. It was time to sell her.
In the replacement yearling ewe group, I had one yearling ewe not produce a lamb. Since she was just a yearling at lambing time, I am giving her one more breeding to produce a lamb for me. She is currently in with a lamb. If there is no lamb in the next five months, I will sell her for slaughter. A ewe that does not produce lambs, costs the sheep farmer money.
I divide my ewes into breeding groups keeping the numbers low. This allows me to breed more ewes with one ram. When one group is lambing, another group is being bred.
Having scheduled lambings enables me to better track the ewes and their lambs. When I first started as a sheep farmer, I let the ram run with the ewes all year. The lambs came at various times. Tracking which ewes were producing lambs was more difficult, and I missed ewes that were not lambing.
The smaller breeding groups with scheduled breeding/lambing times allowed me to see that one of my rams was a low producer. I divide my ewes into groups of 10 to 13 ewes per ram. The first lambing since starting breeding groups, one group of ewes only 40% of the ewes had lambs. The fault was not in the ewes, but in the ram. I had used this ram for three years, letting him run with the ewes all year. I realized some of the ewes I had culled for not producing a ram, may not have been their fault, but the ram’s.
I have made some mistakes during the time of raising sheep. I try to learn from my mistakes and improve the way I record and raise my sheep.
Hope your sheep farming is doing well.