If an animal suffers from a ß-carotene deficiency, the following symptoms or diseases may occur:- lactation heat
- delayed follicle maturation/ovulation
- cysts
- embryonic death
- premature abortions
- susceptibility to infection
Risk factors for ß-carotene deficiency- High silage maize content
- Old grass silage (brown colour)
- High straw content in dry rations
- Low feed intake
- High milk yield
Fresh grass is rich in beta carotene. In contrast, maize silage, straw and cereals contain little beta carotene. The beta carotene content of poor grass silage and poor hay is also low. Also due to the storage period of silage, ß-carotene can become scarce in dairy cattle rations in spring.