Livestock & Feed formula solvers

As-Fed to Dry Matter

M_{DM} = M_{AF} \times DM

Livestock & FeedConverts a weight of feed between the as-fed basis it is handled in and the dry matter basis every ration and feed test is written on. The conversion behind the most expensive mistake in feeding.

Average Daily Gain

ADG = \frac{W_f - W_i}{t}

Livestock & FeedLiveweight gained per day across a weighing period — the measurement that turns two scale readings and a calendar into a growth rate, and the basis of every projection to a target weight.

Blending Two Feeds to a Protein Target

x = \frac{a_t - a_2}{a_1 - a_2}

Livestock & FeedThe share of the higher-protein ingredient needed when blending two feeds to hit a target analysis — the Pearson square, written as the algebra it always was.

Daily Water Requirement of a Herd

W = n \, w

Livestock & FeedThe water a herd drinks in a day, from the head count and the demand per head. Water is the nutrient stock run short of first and the one least often measured.

Dry Matter Intake from Body Weight

DMI = p \times BW

Livestock & FeedDaily dry matter intake estimated as a percentage of body weight — the first figure in any ration, and the one that sets how much of everything else the animal can physically consume.

Feed Conversion Ratio

FCR = \frac{F}{G}

Livestock & FeedFeed consumed per unit of liveweight gained — the headline efficiency figure for any growing animal, and the one that decides whether a feeding period paid for itself.

Feed Cost per Unit of Gain

c_g = \frac{C_f}{G}

Livestock & FeedWhat a kilogram of liveweight cost in feed — the feed bill divided by the weight it produced. The figure that decides whether to sell an animal now or feed it further.

Forage Demand in Animal Unit Months

F = n \, i \, t

Livestock & FeedThe forage a herd will consume over a grazing period, from the animal units, the intake per animal unit and the length of the season. One animal unit month is conventionally 780 lb — about 354 kg — of dry matter.

Grazing Days from Available Forage

D = \frac{F \, u}{I}

Livestock & FeedHow many days a herd can graze a paddock, from the forage standing on it, the share of that forage the animals will actually harvest, and what the herd eats each day.

Manure Storage Volume

V = n \, p \, t

Livestock & FeedThe storage a herd fills over a given number of days, from the head count and the manure produced per head per day. The calculation behind every regulated storage period.

Stocking Rate in Animal Units

SR = \frac{AU}{A}

Livestock & FeedAnimal units carried per unit of grazing land. A stocking rate is a decision the manager makes — how many head went out on the field — and it is not the same quantity as the carrying capacity that decides whether the decision was right.

Total Digestible Nutrients Supplied

TDN = M \, f

Livestock & FeedThe digestible energy a feed delivers, as the mass of total digestible nutrients in it. TDN is quoted as a percentage of the DRY MATTER, so the feed weight has to be on a dry matter basis before this multiplication means anything.