Chapter 4 – Labelling and Guarantees
4.6 Selenium Supplementation of Livestock Feeds

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Livestock Species Excluding Dry and Lactating Dairy Cows

The levels of supplemental selenium (Se) permitted in livestock feed, excluding lactating and dry dairy cattle are:

A) Complete Feeds

  • in complete feeds for swine, chickens, turkeys, ducks, geese, beef cattle, growing dairy cattle (non-lactating heifers, bulls and steers), sheep and goats, at a level not to exceed 0.3 mg/kg.
  • in the dry material of milk replacers for calves, lambs, colts and piglets, at a level not to exceed 0.3 mg/kg.
  • in complete feeds for rabbits and salmonid fish, at a level not to exceed 0.1 mg/kg.
  • in complete feeds for non-food producing livestock, at nutritional levels.

B) Limit fed feeds

  • at a level not to exceed an intake of 3 mg Se/head/day for beef cattle and 0.7 mg Se/head/day for sheep.

C) Free-choice trace mineralized salts and free-choice mineral feeds

  • in free-choice trace mineralized salts for all classes of beef cattle at a level not to exceed 120 mg/kg;
  • in free-choice trace mineralized salts for all classes of sheep at a level not to exceed 90 mg/kg;
  • in a free-choice mineral feed for all classes of beef cattle on range at a level not to exceed 30 mg/kg.

Dry and Lactating Dairy Cows

Per Table 4 of the Feeds Regulations, a complete feed for dairy cows refers to the grain ration. The Sixth Revised Edition (1989) of the Nutrient Requirements of Dairy Cattle suggests a selenium requirement of 0.3 mg/kg of total ration dry matter for dry and lactating dairy cows. The amount of grain ration fed to dairy cows is dependent on a number of factors including; forage quality, body size and condition, milk production, stage of lactation and age. To allow dry and lactating dairy cows access to an appropriate level of supplemental selenium, values have been established with input from industry which would incorporate some of these factors and permit an increased level of selenium supplementation.

The levels of supplemental selenium permitted in feeds for lactating and dry dairy cattle are found in Table 2. These values were calculated based on expected dry matter intakes for dairy cows weighing between 400 and 700 kg using Table 6-1 of Sixth Revised Edition (1989) of the Nutrient Requirements of Dairy Cattle. Values used in the calculation of maximum daily selenium intakes are found in Table 1.

Table 1: Values used to calculate maximum allowable daily selenium intakes

Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
Milk Production 20 kg 25 kg 30 kg 30 kg
Dry Matter Intake % BW 3.6% 3.5% 3.5% 3.2%
Daily Dry Matter Intake 14.4 kg 17.5 kg 21.0 kg 22.4 kg
Maximum Daily Se Intake Dry Matter 4.32 mg 5.25 mg 6.30 mg 6.72 mg

Table 2: Maximum allowable daily selenium intakes

Body Weight 400 kg 500 kg 600 kg 700 kg
Maximum Daily Se Intake (as fed, 95% Dry Matter) 4.1 mg 4.99 mg 5.99 mg 6.38 mg

The feed manufacturer will be responsible for the development of a table of maximum allowable daily intakes for each product for body weights from 400 to 700 kg. This table will be required to appear on the label of each product. It will be calculated using the Maximum Daily Selenium Intakes (95% dry matter, as fed basis) shown in Table 2.

Values for developing the table for the label are obtained using the following equation where all values are expressed on an as fed basis:

Maximum Daily Intake of Product (kg/day) = Maximum Daily Selenium Intake (mg/day) ÷ Product Selenium Level (mg/kg)

For example:

  1. a dairy grain ration containing 0.6 mg/kg added selenium (as fed) would have on its label the following table (not including calculations shown in italics):
    Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
    Maximum Daily Intake of Product (as fed) 4.10 ÷ 0.6 = 6.8 kg 4.99 ÷ 0.6 = 8.3 kg 5.99 ÷ 0.6 = 10.0 kg 6.38 ÷ 0.6 = 10.6 kg
  2. a protein supplement containing 3.0 mg/kg added selenium (as fed) would have on its label one or both of the following tables depending on feeding directions :

    a. Top Dressing

    Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
    Maximum Daily Intake of Product 1.4 kg 1.7 kg 2 kg 2.1 kg

    b. Mixed at 150 kg/tonne finished feed (Ration = 0.45 mg/kg Se)

    Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
    Maximum Daily Intake of Dairy Ration 9.1 kg 11.1 kg 13.3 kg 14.2 kg
  3. a mineral supplement containing 25.0 mg/kg added selenium (as fed) would have on its label one or both of the following tables depending on feeding directions:

    a. Top Dressing

    Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
    Maximum Daily Intake of Product 164 g 200 g 240 g 256 g

    b. Mixed at 30 kg/tonne finished feed (Ration = 0.75 mg/kg Se)

    Body Weight (BW) 400 kg 500 kg 600 kg 700 kg
    Maximum Daily Intake of Dairy Ration 5.5 kg 6.7 kg 8 kg 8.5 kg

    Labels for all feeds containing selenium for dry and/or lactating dairy cows, regardless of product selenium level, must contain the aforementioned table indicating maximum product intakes. Any labels which do not contain the aforementioned table will be considered in violation of the Feeds Act and Regulations and will be subject to enforcement action.

    Any products containing the higher selenium levels will, of course, be required to bear labels reflecting the higher supplemental levels and the required table prior to being marketed.

    Note 1: Beef cattle, sheep, goats and dairy cattle may receive only one source of supplemental Se.

    Note 2: The minimal level of supplemental Se may be as low as 30% of the maximum permitted.

Labelling Requirements For All Species Including Dry and Lactating Dairy Cows

The following information is required on the labels of feed containing supplemental Se in addition to the specific requirements for feeds designed for feeding to dry and lactating dairy cows:

  1. Immediately above the guaranteed analysis
    "This feed contains added selenium at space mg/kg".
  2. Caution to appear on all feed labels:
    "Directions for use must be carefully followed".
  3. Caution to appear on cattle, goat and sheep feed labels:
    "Do not use in association with another feed containing supplemental selenium".

Additional Label Information

Permission has been granted under Section 30 (b) of the Feeds Regulations to allow a "total" actual selenium guarantee, expressed in mg/kg to appear on feed labels.

In order to proceed with a "total" guarantee, manufacturers must notify the Animal Feed Division and receive approval for the guarantee. In addition, the company must provide the feed formulation to justify the level guaranteed, as well as submit information on manufacturing quality control to demonstrate that the total guaranteed will be maintained consistently.

Based on statistical analysis of analytical results, a permitted analytical tolerance of plus/minus (40% of the selenium guarantee + 0.02 mg/kg) will be utilized to determine compliance of any product to its guaranteed level of "total" actual selenium.

The level of "added" selenium is still required to be stated on the feed label.

Mixing Ability

No difficulties have been encountered by feed manufacturers in mixing supplemental Se when producing feeds using macro-premixes or supplements containing Se. Firms using either a macro-premix or supplement from a firm previously cleared for mixing supplemental Se will not have to show proof of mixing ability.

If, however, a feed mill is manufacturing any of the following types of feed, a clearance demonstrating Se mixing ability is required:

  1. Selenium premixes (Se and carrier).
  2. Micro-premixes containing Selenium.
  3. A feed where one of the above types of premixes has been used.

    In order to obtain a clearance, we would ask that you submit one sample from each third of a batch (total 3 samples) of feed to a reputable laboratory for a Se assay. The results of that assay should be maintained at the feed mill and be made available to CFIA upon request.

Veterinary Prescriptions

Pursuant to Section 5 (2)(g)(v) of the Feeds Regulations, all veterinary prescriptions which prescribe supplemental selenium levels in excess of 0.3 mg/kg, in the total diet, for any class of livestock, must be submitted by the manufacturer of the feed, within 10 working days of the time of initial manufacture of the veterinary prescription feed.

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