Scissor Cut Results 5/4/2021

On Your Mark

Welcome to the first Forage Quality Scissors Cut report for 2021. This year we are sampling 42 sites in Delaware County and the NYC Watershed.

Grass and legume heights measured this week are right at the average for the past 15 years. But grass fields tested in the high 40s NDF, higher than is typical for this week. NDF will often decrease between the first and second weeks in May, so next weeks results will be important to watch. Over the past years of sampling, the average date for grasses to reach target NDF has been May 16, it looks that 2021 will see average to early maturity.

The Table below has each sample location, listed by Town and elevation, and lists the species sampled, average height, Neutral Detergent Fiber (NDF), Neutral Detergent Fiber Digestibility (NDFD), and Total Digestible Nutrients (TDN). We have sampled grass, legume and mixed legume/grass fields across the county and at elevations from 1070 to 2200 feet. Look for locations with similar forage type and elevation to your farm.

For 2021 we will be reporting several measures of forage quality.  Different types and groups of cattle have different demands and each measure tells a slightly different story.  If harvesting for dairy forage, we suggest harvesting based on NDF, for beef choose and appropriate TDN target or the animals you will be feeding.

NDF – Neutral Detergent Fiber is a measure of the structural fiber in a feed sample. NDF correlates well with how much forage a cow can eat (gut fill). Earlier cut hay = lower NDF = higher dry matter intake = higher performance.

NDF goals for Dairy Cattle Forage:  Grass hay and silage  – 48 – 55%, MMG hay & silage – 40 – 50%, MML hay & silage – 38 – 45%, Legume hay & silage – 36 – 42%

NDFD – NDF Digestibility As forage plants mature, the fiber percentage increases, and at the same time the digestibility of the fiber decreases.  NDFD measures the digestibility of fiber by rumen fluid.  We report 24hr NDFD as an indicator of forage digestibility.  Higher digestibility = more energy available from a forage.

TDN – Total Digestible Nutrients The sum of the digestible fiber, protein, lipid, and carbohydrate components. TDN is a measure of energy available from forage and is related to digestible energy.  TDN is useful for beef cow rations that are primarily forage.  Higher TDN values indicate higher energy available, cattle groups with higher energy demands require higher TDN intakes.

TDN goals for Beef Cattle Forage: Growing Calf (2lb ADG) 70 – 72, Growing Yearling (2lb ADG) 64 – 66, Lactating Beef Cow 60 – 64, Mature Dry Cow 52 – 55

Special thanks to Dairy One for providing the sample analysis