Mr Freeman said farmers "are at the mercy of the weather" and there is cause for concern for farmers who will have a lower cash flow due to this season's cooler weather.
Along with milk, feed and grass, vitamin D is essential for lamb growth.
Mr Gourlie said recent weather causes the lambs to use most of their energy to keep their body temperature stable, as opposed to using it for protein and growth.
According to Mr Gourlie, sheep in the region have also been impacted by the long term consequences of facial eczema; which broke out earlier this year.
"It was the perfect storm with the wet weather, spawn in the ground and dry matter," he said.
Wool loss, scabby skin and liver damage can stress pregnant ewes and cause them to lose condition, all of which could impact the health of the lambs.
Mr Gourlie said the kill market runs from the first week of November, with the last "chilled boat" leaving for the United Kingdom on the 4th of November.
Mr Gourlie said many lambs didn't make the chilled market this year due to being underweight and were subsequently a part of the frozen market; which is less profitable.
"It's a concern financially for the farmers because they missed the chill period," Mr Gourlie said.
He said he is looking forward to the warm weather this week as it is good news for farmers.
Hawke's Bay farmer Leicester Gray said his livestock seems to have "escaped" the facial eczema outbreak and are doing well.
Mr Gray currently farms 3300 breeding ewes on Fairfield Road in Waipawa and said he got 5000 lambs from his ewes this year and bought an additional 5-600 lambs.
Despite hearing reports of concern from other local farmers, Mr Gray said he is happy with the health and growth of his lambs.
"We started lambing at the end of July and started drafting around the 9th of October. The lambs have been weighing in at 17.6kg and I'm quite happy with that weight," he said.
Mr Gray said he is on track with the kill schedule, having killed 2800 lambs already.
