ANSC Feeds Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Cows tend to consume less poor-quality grass hay compared to good-quality grass hay primarily due to the negative relationship between dry matter (DM) intake and the total digestible nutrients (TDN) to crude protein (CP) ratio. Poor-quality hay typically has a lower nutritional value, meaning it provides less energy and fewer nutrients per unit of dry matter consumed. When cows are offered lower quality forages, their intake rate decreases as they naturally adjust their consumption in response to the decreased energy and protein availability.

A low TDN means that the forage is less digestible and provides fewer energy resources necessary for the animal's metabolic needs. Conversely, when cows consume higher quality hay, which has a higher TDN and better protein levels, their energy and nutritional needs are met more efficiently. As a result, they are more likely to increase their intake of this better-quality forage.

Higher moisture content can sometimes affect palatability, but is not the primary factor in the consumption difference between poor and good-quality hay. The TDN to CP ratio provides a clearer insight into why cows adjust their intake in relation to forage quality. Flavors of the forage can also play a role in consumption preferences, but again, the nutritional value as reflected in the TDN: