In cow milk, protein, fat and S.N.F. decline with -

Correct option is C

· Correct answer: (c) Age
· As cows age, protein, fat, and solids-not-fat (S.N.F.) in milk typically decrease. Older cows generally produce milk with lower quality components compared to younger cows.
Other options:
· (a) Season: Seasonal changes can affect milk production but not as significantly as age.
· (b) Breeding: Breeding can affect milk yield but not the decline in milk quality.
· (d) Management: Proper management can maintain milk quality but is not the main factor in age-related decline.