Feed Inventory for the Dairy Herd: Planning for Shortages

By Virginia Ishler and Tim Beck

Introduction

Weather conditions such as drought or excessive rainfall during the growing or harvest season can create challenges related to forage and feed inventory. Planning and preparing for quality and quantity shortfalls can avoid reductions in animal performance and excessive purchased feed cost. Managing farm feed inventory and considering feed allocation for the various animal groups is one strategy to overcome unexpected surprises. This document is not intended for ration balancing. It is designed to help the dairy producer or consultant determine if forages available on the farm are adequate to meet the dairy herd's basic needs for effective fiber (forage neutral detergent fiber) and the amount of concentrate necessary to meet the animal's energy and protein requirements. It also takes into account the potential feed costs involved when adjusting feed inventory because of extreme weather conditions.

Market Prices Compared to Home-Raised Feed Costs

Forages

Market costs for various feeds can be obtained from several sources. Monthly prices can be obtained from USDA Economics, Statistics and Market Information System Prices are reported for the US and various states. The alfalfa hay price represents legume forages, the mixed hay price represents mixed mostly legume forages, and the other hay price grass and mixed mostly grass forages. Local auction results on a weekly basis can be obtained from Ag Market News, which includes Pennsylvania and Maryland. Figure 1 illustrates the calculations for determining market prices for ensiled forages. Table 1 shows the cost to produce home-raised feeds sorted by return over labor and management. Home raised feed prices should be lower than the market price.

Figure 1. Example calculations for ensiled forages using market hay prices.

Haylage: Divide the respective hay price by 0.90 and multiply by the haylage dry matter percent.
Example:
Legume haylage with 41.5% dry matter and legume hay @ $245/ton
$245 ÷ .90 x .415 = $112.97/ton.

Corn silage: Divide the other hay price by 0.90, multiply by 0.75, and multiply by the corn silage dry matter percent.
Example:
Corn silage with 33.5% dry matter and grass hay @ $196/ton
$196 ÷ .90 x .75 x .335 = $54.72/ton.

Table 1. Home raised forage crop enterprise analysis combined for years 2016 and 2017 and sorted by return over labor and management.1

1Based on 25 Pennsylvania dairy farms participating in two-year (2016-2017) Crops to Cow project (Ishler, Goodling, & Beck, 2018) and analyzed with RankEm software (Minnesota, 2018b).

Grains
The market sources listed for forages also apply to grains. Prices are listed on a per bushel basis. Prices per bushel can be converted to a per ton basis by multiplying the respective grain price by the bu/cwt factor, adding $.40 for mixing and/or grinding, and multiplying by 20 (Figure 2). Figure 3 lists the conversion factors for bushel per hunderweight or pounds per bushel. Table 2 shows the cost to produce home-raised corn and soybeans sorted by return over labor and management. The price to raise grains on farm should be lower than the market price.

Figure 2. Example calculations for determining market prices for corn and soybeans.

Shelled corn price:
$4.12/bu x 1.79 bu/cwt = $7.37/cwt + $0.40 = $7.77/cwt x 20 = $155.40/ton as-fed

Raw soybeans:
$8.31/bu x 1.67 bu/cwt = $13.88/cwt + $0.40 = $14.28/cwt x 20 = $285.60/ton as-fed.

Table 2. Home raised grain crop enterprise analysis combined for years 2016 and 2017 and sorted by return over labor and management.1

Based on 25 Pennsylvania dairy farms participating in two-year (2016-2017) Crops to Cow project (Ishler, Goodling, & Beck, 2018) and analyzed with RankEm software (Minnesota, 2018b).

Figure 3. Conversion factors for bushel weights.

Herd Information

The number of days that forages and grains need to be fed should be calculated so they can be allocated to the various animal groups. This will vary by farm depending on when animals can go out on pasture or when another forage can be harvested. A rule of thumb is a minimum of 1.5 acres per cow to meet the feed requirements of the herd (Table 3). Feeding losses as a percent should be factored into forages and grains required and usually range from five to ten percent in most farm situations.

Table 3. Example calculation of acres needed to feed a 70-cow milking herd.

Dry Matter Intake Appropriate for Production, Maintenance, and Growth

Milk Cows

Rations formulated for all animal groups are developed based on intake requirements for production, maintenance, or growth. For the lactating cows use the milk check for average milk production and components to calculate energy corrected milk (Figure 4). Actual dry matter intake should be used and not the number from a ration program to compare against the recommendation as a percent of body weight (Table 4). The amount of concentrate as a percent of the total ration dry matter can range from 35 to 60 percent depending on the quality and quantity of forages available and the composition of the concentrate ingredients.

Figure 4. Example illustrating the calculation of energy corrected milk.

Energy corrected milk (ECM) equation: (12.82 * fat lbs.) + (7.13* protein lbs.) + (0.323*milk lbs.)
Source:Tyrrell and Reid. 1965. J. Dairy Sci. Vol. 48, 9:1215-1223

Table 4. Guidelines for total dry matter intakes by large breed dairy cattlea

aMilk producing small breeds may consume 0.5% more dry matter per cwt of body weight at a given level of milk production.
Example: Average body weight is 1350 pounds for a lactating cow averaging 80 pounds of energy corrected milk (ECM). Estimated dry matter intake is 1350 x .038 = 51.3 pounds
Source: Dairy Reference Manual Third Edition, NRAES-63, 1995.

Dry Cows and Heifers

Rations formulated for dry cows focus on maintaining body condition during the 60-day dry period (Table 5). Heifers are fed to optimize growth to achieve adequate body weight at breeding age so they can freshen between 22 and 24 months of age (Table 6). Dry cows and heifers can utilize higher fiber forages and byproduct feeds. It is recommended to limit corn silage to these groups as they can become over-conditioned due to excessive energy intake.

Table 5. Guidelines for feeding dry cows.

aUse the lower level when corn silage provides the majority of the forage dry matter.
bDry matter intake will be lower on rations containing high fiber forages (forage NDF greater than 55 percent). An example would be diets containing straw.
Source: Dairy Reference Manual Third Edition, NRAES-63, 1995.

Table 6. Guidelines for feeding dairy young stock

aUse the lower level when corn silage provides the majority of the forage dry matter.
Source: Dairy Reference Manual Third Edition, NRAES-63, 1995.

Basic Nutritional Guidelines

When forage inventory is limited and adjustments to rations are necessary to keep diets relatively consistent, adequate forage fiber is a key metric to monitor. Maintaining forage neutral detergent fiber levels in the diet as a percent of body weight can avoid problems with subclinical acidosis or milk fat depression. Table 7 provides recommendations on minimum and maximum levels for forage NDF (FNDF) and total NDF (TNDF). Also, various roughages and concentrates can be utilized to replace some home raised feeds that are in short supply and can help keep total NDF in line when forages are limited. Most of these ingredients can be fed in limited amounts to provide added fiber, protein, or energy (Figure 6).

Table 7. Recommended forage neutral detergent fiber (FNDF) and total neutral detergent fiber (TNDF) levels.

Example: A lactating herd averaging 80 pounds of energy corrected milk and a body weight of 1350 pounds is consuming:
Corn silage – 20 dry matter pounds with 40% NDF = 8.0 pounds of NDF
Haylage – 10 dry matter pounds with 43% NDF = 4.3 pounds of NDF
8.0 + 4.3 = 12.3 pounds FNDF / 1350 = .91% FNDF as a percent of body weight

The ration contains 31.5% NDF and animals are consuming 52 pounds of dry matter. The TNDF pounds is 16.38/1350 = 1.21% TNDF as a percent of body weight.

Figure 6. Suggested maximum intakes for various ingredients in rations for dairy cattle.

aWhen two values are given, the second is for a pellet.
bRefers to percent of ingredient dry matter as a percent of total ration dry matter.
cRoughages with a value in concentrate column may be used to meet fiber minimums in a concentrate mixture.
Source: Dairy Reference Manual Third Edition, NRAES-63, 1995.

Calculating for Planned Shortages

To plan for forage shortages it is necessary to estimate yields and assess storage structures. Feeding strategies can be developed knowing how much feed is available. This can include limiting amounts fed, adjusting the byproduct feeds used, or eliminating the forage from heifer diets and purchasing forages. The following is a case farm that is planning for a shortage of corn silage due to drought conditions:

Thirty-five acres were planted for corn silage yielding 12 tons per acre for a total of 420 tons. In previous years corn silage had yielded 18 tons per acre for a total of 630 tons. This herd feeds corn silage to the lactating and dry cows as well as the older heifers. This herd typically averages 49 milk cows, 7 dry cows, and 28 heifers over 12 months of age. This producer wants to feed corn silage for 12 months and needs to determine how much corn silage can be fed to make it last.

Typical ration:
49 milk cows x 60 as-fed pounds of corn silage x 365 days = 536.5 tons
7 dry cows x 15 as-fed pounds of corn silage x 365 days = 19 tons
28 heifers x 8 as-fed pounds of corn silage x 365 days = 40.8 tons
Total = 596 tons with a 5% feeding loss = 626 tons harvested. This farm rarely has any corn silage carry over year to year.

If the focus is to supply the lactating herd corn silage throughout the year and maintain a 5% feeding loss, then the milk cows will consume 44 pounds of corn silage. (49 cows x 44 pounds of corn silage x 365 days = 393 tons (5% feeding loss = 413 tons harvested).

Alternative forages or byproducts will be needed for the dry cows and heifers. A nutritionist can formulate rations with other home raised forages or purchased forages to meet the fiber, protein and energy requirements of those groups. Total feed costs should be examined to evaluate their impact on the breakeven cost of production.

Ration Costs

Feed costs, both home raised and purchased typically make up the largest expense on a dairy operation. This can be amplified when weather conditions compromise feed inventory and more purchased forages and grains are needed. Purchased concentrates have been the target of criticism when feed costs are too high. However, based on work conducted by the Extension Dairy Business Management Team at Penn State, it is the home-raised feed costs that are contributing to the higher feed costs. High unit costs of home-raised feeds results from low yields, which would not be unexpected during adverse weather conditions. Harvesting low quality feeds may require additional purchased feed to compensate, which can increase the total feed costs. The goal is to evaluate current inventories and develop the best strategy to maintain animal performance while keeping total feed costs in line.

There can be a substantial range in total feed costs on-farm ranging from a low of $1700 to a high of $3000/cow depending on the year. Farms at the high end of the range for feed cost typically are purchasing a complete grain mix for the lactating herd, have challenges in their cropping program, and are purchasing a lot of forages for the heifers. The farms with very low feed costs have an extremely efficient cropping program, are producing all the forages needed for the herd, and are usually raising corn grain and/or soybeans to be fed along with a commodity feed to minimize the amount of purchased complete feed (Table 8).

Monitoring income over feed cost (IOFC) is a metric that can help evaluate how the milk cows are performing relative to the ration being fed. This does require knowing the herd’s breakeven IOFC to determine if cows are making or losing money. IOFC can be calculated monthly and provides valuable information sooner versus later if ration changes are needed.

Table 8. Average feed costs for herds based on net return over labor and management for 2016 through 2018.

1Based on Pennsylvania dairy farms participating in Crops to Cow project (Ishler, Goodling, & Beck, 2018) and analyzed with RankEm software (Minnesota, 2018b).

Summary

Planning for forage or grain shortages due to extreme weather conditions can minimize negative effects to animal performance and to the profit margin. Since feed costs represent a significant portion of the farm expenses, developing strategies to manage compromised forage quantity and/or quality earlier versus later can avoid a lot of animal production, health, reproduction and financial problems in the future.