Proposal – Maximum Nutrient Values in Horse Feeds

July 2018

Purpose

As part of a comprehensive, multi-year regulatory modernization process, the Canadian Food Inspection Agency (CFIA) has initiated the renewal of the federal Feeds Regulations (Regulations) as one of several priorities identified for modernization.

The goal of renewing the Regulations is to develop a modernized risk- and outcome- based regulatory framework for feeds which:

  • safeguards feeds and the food production continuum
  • attains the most effective and efficient balance between fair and competitive trade in the market
  • minimizes regulatory burden

Modernization of the Regulations provides the opportunity to review feed controls, standards, labelling and other regulatory requirements. The purpose of this proposal is to:

  • review the nutrient content standards for horse feeds set out in Table 4 of Schedule I of the current Regulations which the CFIA has used to exempt complete feeds and some supplements from registration
  • recommend possible updates or amendments to the current requirements

Background and current situation

Table 4 of Schedule I was created and incorporated into the Feeds Regulations in the 1980s as a mechanism to exempt certain groups of feeds from mandatory registration. The original Table 4 established nutrient ranges (minimums and maximums) as exemption criteria for feeds for chickens, turkeys, swine, beef and dairy cattle, and sheep. In 1990, via two regulatory amendments, the table was first expanded to include horses, goats, ducks, and geese; and then for rabbits, mink, and salmonid fish. Since that time, there have been no other substantive changes to the table or to any of the nutrient ranges.

Currently, the feed can be exempted from registration if:

  • a complete feed provides nutrients which fall within the ranges listed in Table 4 or
  • a supplement has directions for use which would result in a complete feed that provides nutrients which fall within the Table 4 ranges

Feeds that provide nutrients which fall outside the ranges listed in Table 4, and that do not meet any additional exemption criteria, require assessment and registration by the CFIA prior to manufacture and sale. However, complete feeds intended for feeding to livestock not intended for human consumption and which are in packages up to 5 kg are exempt from any requirements of the Feeds Act and Regulations altogether.

In the case of horse feeds, the original Table 4 established nutrient ranges for complete feed (grain portion) only. However, the National Research Council's Nutrient Requirements of Horses (2007) ("NRC") reports several nutrient requirements for horses on a total diet dry matter basis. Many factors – breed, size, reproduction stage, lactating stage, climate, type of forages and grains, on-farm feed management and practices, environmental conditions among others – have an impact on the variability of the daily feed intake. As the total daily ration for horses includes forages, establishing nutrient ranges on the basis of complete feeds only does not take into consideration the nutrient contribution from the forage portion of the total daily diets and may lead to over supplementation of certain nutrients, especially when the forages contain high levels of nutrients and constitute a greater proportion of the daily diets.

As indicated in the Feed Regulatory Renewal Consolidated Modernized Framework Proposal, both the CFIA and stakeholders recognize that some of the values in Table 4 may no longer have the same nutritional relevancy that they did when the table was first introduced. Stakeholders have also indicated that they feel that Table 4 prevents innovation for new feed products. However, many of the maximum nutrient levels which are currently set out in Table 4 have health and safety implications that must be considered.

Proposal

It is proposed that:

  • Table 4 be removed from the Regulations and no longer serve as a trigger to register feeds based on specified ranges of nutrient content
  • maximum nutrient levels be established and incorporated by reference for horse feeds
  • the proposed maximums are established based on total daily diets rather than for complete feeds only
  • the exemption for complete feeds intended for animals not intended as food for human consumption will be raised to packages containing up to 10 kg

This proposed approach addresses stakeholder concerns regarding Table 4 and its relevance in current industry practices, as well as claims that the nutrient ranges provided in Table 4 impede new products from entering the marketplace. Furthermore, it addresses concerns regarding the harmful impact that higher levels of certain nutrients may have on livestock or the resulting food products, and underscores the modernized regulatory framework's focus on health and safety for humans, animals, and the environment.

It is further proposed that:

  • minimum levels for nutrients will no longer be established, however feeds will still be required to be suitable for their intended purpose and must meet an animal's nutritional requirements
  • maximum levels for nutrients will be established by species or classes of species, as appropriate
  • nutrient maximum levels will be incorporated by reference in the Feeds Regulations to facilitate updating as necessary

Considerations

There remains a need for an enforceable regulatory framework regarding maximum nutrient concentrations in livestock feeds for health and safety reasons. For instance, levels of certain vitamins in livestock rations (for example, vitamins A, D, and E) in excess of nutritional requirements can be harmful to livestock or can be concentrated into tissues that are used for human consumption, thus posing potential risk to human health. Similarly, certain minerals (for example, copper, iodine, phosphorus and zinc) fed in excess of livestock requirements can also contribute to increased human and environmental risks.

A significant proportion of minerals fed in excess of requirements are excreted into the environment via urine and feces. Consequently, even though the maximum tolerable level (MTL) of a given mineral may be significantly greater than the nutritional level, feeding at the maximum tolerable level may result in a negative impact on the environment.

An analysis of horse nutritional requirements and maximum tolerable dietary nutrient levels was conducted by the CFIA with the following scope:

  • to determine those nutrient levels that may impact the health and safety of the respective livestock, humans, and environment
  • to determine those nutrient levels that support a nutritional purpose as opposed to a therapeutic purpose
  • to determine those nutrient levels that may produce residues in the resulting food that could be harmful to those consuming the products.

Information sources used in the review and development of nutrient maximums in horse feeds included:

Appendix I setsout the proposed maximum nutrient values for horse feeds.

The current Table 4 nutrient values to exempt feeds from registration are for the complete feed (grain portion of diets only) on an "as fed" basis (assumed 90% dry matter), assuming a fixed intake for horses. In contrast, the proposed maximum nutrient levels are to be applied to the total dietary intake. These proposed maximums were derived taking into consideration typical total daily diets for horses and ranges for nutrient content of the forages (where known) as well as complete feeds (grain portion) and are reported on a "dry matter" basis. The proposed maximum nutrient concentration in the daily diet has been set high enough to provide flexibility to formulate nutritionally and environmentally sound diets.

While the NRC requirements for vitamins are on a supplemental basis and the maximum values indicated in this proposal are on a total diet dry matter basis, the proposed values are over and above the NRC requirements such that contributions from the grain and forages, though variable, would not result in values exceeding the stated maximums.

Notes on some of the considerations incorporated into setting the maximum value are provided at the bottom of the tables for each nutrient in the Appendix.

Anticipated outcomes

This modernized regulatory approach to the oversight of maximum nutrient content in horse feeds would:

  • give regulated industry the flexibility to manufacture feeds with nutrient contents that meet their customers' needs without requiring pre-market assessment and authorization
  • allow the CFIA to maintain regulatory oversight for hazards that may negatively impact human or animal health or the environment
  • allow for timely updates to the standards as new information concerning specific nutrients is provided
  • reduce the regulatory burden on industry wishing to get innovative products into the marketplace

Stakeholders are being provided with an opportunity to comment on all proposals, including the maximum nutrient values being suggested for each species or class of species, before they are incorporated into a regulatory framework.

References: A complete bibliography is available upon request

Have your say

The CFIA is seeking feedback on the proposal to modify the regulatory requirements related to maximum nutrient content in livestock feed:

  • Do you have any concerns with the proposal to remove the Table 4 nutrient levels from the Feeds Regulations and no longer exempting feeds from registration based on the nutrient content of the feeds?
  • Do you have any concerns with the proposal to establish maximum nutrient values for livestock feeds?
  • Do you have any concerns with the proposed maximum nutrient values outlined in Appendix I for horse feeds?
  • Do you have any concerns with raising the exemption for complete feeds not intended for food-producing animals in packages containing up to 5 kg to packages containing up to 10 kg?
  • Would the proposed amendments to the Feeds Regulations be effective in protecting human and animal health and the environment?
  • Are there options not mentioned in this proposal that should be explored?
  • Any additional feedback?

We strongly encourage you to provide your input and feedback, which is critically important to the success of the regulatory modernization initiative.

Please send written comments by 08/17/18 to:

Sergio Tolusso
Canadian Food Inspection Agency
Animal Feed Division
59 Camelot Drive
Ottawa, ON K1A 0Y9

Email: Sergio.tolusso@canada.ca
Fax: 613-773-7565

Appendix I – Proposed maximum nutrient values for horse feeds

Horse classes and average intakes: (dry matter basis (DM))
Class Range of DM intake
(% body weight (BW))Table note 1
Forages
Horses (Mature and growing) 1.5 to 3.2 Up to 90%

Table Note

Table Note 1

Adapted from NRC (2007). Nutritional Requirements of Horses Sixth Revised Edition. Washington, DC, The National Academies Press.

Return to table note 1  referrer

Macro-minerals

Calcium (Ca)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) 2 2

Considerations:

  • maximum tolerable level (MTL) for dietary Ca is 2% total diet DM for horses, provided sufficient available phosphorus (P) in the diet (Ca:P ratio between 1 and 6 considered safe for horses) (NRC, 2005)
  • higher levels of dietary Ca can affect the metabolism of P and magnesium (Mg) (Vervuert et al., 2006; NRC, 2005; van Doorn et al., 2004; Grace et al., 2003)
Phosphorus (P)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) 2 1

Considerations:

  • MTL for dietary P is 1% total diet DM for horses, assuming an appropriate Ca:P ratio (Ca:P ratio between 1 and 6 for considered safe for horses) (NRC, 2005)
  • increased incidence of nutritional secondary hyperparathyroidism and dyschondroplasia in horses fed diets with P in excess of 1% and a Ca:P ratio less than 1 (NRC, 2005; Savage et al., 1993)
  • dietary P fed above NRC (2007) requirements is associated with increased total P and water soluble P excretion in horse manure. Dietary P should be limited to reduce the risk of P runoff from waste or manure applied to soil (Westendorf and Williams, 2015; Weir et al., 2013; Ogren et al., 2012)
Magnesium (Mg)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) 0.3 0.8

Considerations:

  • Mg ranges from 0.1 to 0.3% DM in common feedstuffs and horses appear to tolerate alfalfa hays containing up to 0.5% Mg (NRC, 2007; Lloyd et al., 1987)
  • MTL for dietary Mg is 0.8% total diet DM for horses (increased from 0.3%) (NRC, 2005)
  • potential non feed use as a calming supplement at higher levels (approximately 21 g total diet) (Dodd et al., 2015; NRC, 2007)
Sodium (Na)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) 1.2 2.4

Considerations:

  • NRC (2005) suggested that horses can consume about 1 g salt/kg body weight (BW) (6.6% salt or approximately 2.6% Na diet for a 450 kg horse, fed 1.5% BW DM) without adverse effects on feed intake but more than 2.5 g salt/kg BW (approx. 16.7% salt or 6.7% Na) will have adverse effects, including mortality, in most livestock
  • MTL for dietary sodium chloride is 6% (approx. 2.4% Na) total diet DM for horses (NRC, 2005)
  • as long as sufficient fresh water is available, excess Na will be excreted in the urine
Potassium (K)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) 3 3

Considerations:

  • NRC (2005) lowered the MTL for dietary K to 1% in the total diet DM for horses from 3% (NRC, 1980) indicating that it was safe at 1% but not identifying an unsafe concentration
  • K in common feedstuffs typically ranges between 0.3 and 2% DM (NRC, 2007) and in some cases hays (alfalfa) as high as 2.6%
  • horses with a history of hyperkalemic periodic paralysis and compromised kidney function are at a greater risk of hyperkalemia
Sulfur (S)
Class Current
(% of complete feed, as fed)
Proposed
(% of total diet DM)
Horse (All) NRS (No requirement specified) 0.5

Considerations:

  • 0.15% S DM is recommended for horses by NRC (1989)
  • MTL for dietary S is set at 0.5% total diet DM for horses (NRC, 2005)

Trace minerals

Cobalt (Co)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) 10 1

Considerations:

  • NRC (2007) recommended minimum Co dietary requirement for horses is 0.05 mg/kg dietary DM, which is lowered from the previous NRC (1989) recommendation of 0.1 mg/kg dietary DM
  • MTL for dietary Co is 25 mg/kg total diet DM for horses (NRC, 2005)
  • European Union (EU) authorized total maximum Co content is 2 mg/kgfor all species diets (Commission Regulation (EC) No 1334/2003)
  • European Food Safety Authority (EFSA) (2012; 2009) recommended limiting Co supplementation in complete feed to a maximum of 1 mg/kg for all species
  • Co and Co compounds pose a risk to workers during mixing and feeding, due to their dusting potential and presumed carcinogenicity after inhalation (EFSA, 2012; 2009; Agency for Toxic Substances and Disease Registry (ATSDR), 2004)
Copper (Cu)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) 125 125

Considerations:

  • NRC (2007) recommended minimum dietary Cu requirements range from 10 to 12.5 mg/kg DM for horses
  • MTL for dietary Cu is 250 mg/kg total diet DM for horses (NRC, 2005)
  • European Union authorized total maximum Cu content is 25 mg/kg for "other species" diets (Commission Regulation (EC) No 1334/2003)
  • EFSA (2016) recommended reducing Cu in livestock feed to limit potential environmental effects, specifically antimicrobial resistance
Iodine (I)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Pregnant and lactating mares Not applicable (N/A) 3
Horse (All others) 2.5 4

Considerations:

  • NRC (2007) recommended minimum dietary I requirements range from 0.35 to 0.4 mg/kg DM for horses
  • MTL for dietary I is 5 mg/kg total diet DM for horses (NRC, 2005)
  • European Union (2004/C 50/01) maximum authorized I content is 4 mg/kg (total) of complete feed for equines
  • EFSA (2013; 2005) Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) recommended a maximum dietary I content of 3 mg/kg feed based on the link between excessive I supplementation in pregnant mares and increased incidence of goiter in foals
  • increased incidence of enlarged thyroids in foals born to mares fed ≥ 35 mg I/day (Driscoll et al., 1978; Drew et al., 1975; Baker and Lindsey, 1968)
Iron (Fe)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) 500 500

Considerations:

  • NRC (2007) recommended dietary Fe requirements range from 40 to 50 mg/kg DM for horses
  • 100 to 250 mg Fe/kg are typically found in forage and by-product ingredients
  • MTL for dietary Fe is 500 mg/kg total diet DM for horses (NRC, 2005)
  • European Union authorized maximum content of Fe in complete feedingstuffs is 750 mg/kg, for "other species" (Commission Regulation (EC) No 1334/2003)
  • NRC (2005) MTL was chosen as the maximum Fe level in the current proposal despite indications that horses may tolerate higher levels of dietary iron, due to the lack of recent literature to support the claim
Manganese (Mn)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) 400 150

Considerations:

  • NRC (2007) recommended dietary Mn requirement is 40 mg/kg DM for all horses
  • MTL for dietary Mn is 400 mg/kg DM for horses (NRC, 2005)
  • European Union authorized maximum content of Mn in complete feedingstuffs is 150 mg/kg, for "other species"(Commission Regulation (EC) No 1334/2003)
  • EFSA (2016) FEEDAP Panel confirmed safety of 150 mg/kg Mn complete feed for equines along with reduced risk associated with workers exposed to Mn dust as it can cause respiratory and neurological toxicity when inhaled
Selenium (Se)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) No requirement specified (NRS) 1.0 (total)

Considerations:

  • Se concentrations in feedstuff range from 0.01- 0.3 mg/kg depending on Se content in the soil and pH (NRC, 2007)
  • NRC (2007) recommended dietary requirement is 0.1 mg/kg DM
  • MTL for dietary Se in horses is 5 mg/kg DM was set considering animal health (only) and lower levels are necessary to avoid excessive accumulation in edible tissues (NRC, 2005)
  • NRC (2007) indicates that feeding greater than 0.5 mg/kg DM is not necessary
  • EFSA suggests a maximum of 0.5 mg Se/kg diet (EFSA FEEDAP Panel 2016)
  • The CFIA provided Health Canada with data on Se transfer to milk, meat, and eggs. Health Canada assessed this data and has indicated that 1 mg/kg total selenium in the diet should not result in Se concentrations of concern in foods of animal origin
Zinc (Zn)
Class Current
(mg/kg of complete feed, as fed)
Proposed
(mg/kg of total diet DM)
Horse (All) 500 150

Considerations:

  • NRC (2007) recommended minimum dietary Zn requirement for horses is 40 mg/kg DM
  • MTL for dietary Zn is set at 500 mg/kg total diet DM for horses (NRC, 2005)
  • European Union authorized a maximum Zn content of 150 mg/kg in complete feedingstuffs for "other species"
  • long term application of manure to farmland could pose future risks to soil and surface waters, based on the EU's currently authorized Zn levels in feed (EFSA, 2014; Monteiro et al., 2010)
  • EFSA (2014) further recommended a reduction in the maximum Zn limit in complete feed for horses to 100 mg/kg based on environmental concerns including antimicrobial resistance

Vitamins

Vitamin A
Class Current
(IU/kg)
Proposed
(IU/kg of total diet DM)
Horse (All) 40,000 16,000

Considerations:

  • maintenance level of Vitamin A for horses is 30 IU/kg bodyweight. For growth, the requirement is 45 IU/kg bodyweight, while for breeding, gestation, and lactation it is 60 IU/kg bodyweight (NRC, 2007)
  • presumed upper safe level of vitamin A for horses is 16,000 IU/kg diet (NRC, 1987)
  • NRC (2007) suggested that horses likely tolerate more than the upper safe level but due to lack of data, a higher level could not be proposed
  • a study found foals accumulated significantly more vitamin A in their livers than calves fed similar diets (Alvarez et al., 2015)
Vitamin D
Class Current
(IU/kg)
Proposed
(IU/kg of total diet DM)
Horse (All) 5,000 4,000

Rationale:

  • NRC (2007) recommended dietary vitamin D requirements range from 300 to 800 IU/kg DM for horses not exposed to sunlight
  • presumed upper safe level of vitamin D3 for horses is 2200 IU/kg diet, when exposure is greater than 60 days
  • European Union authorized maximum content for vitamin D3 in feedingstuffs for equines is 4000 IU/kg (2004/C 50/01)
Vitamin E
Class Current
(IU/kg)
Proposed
(IU/kg of total diet DM)
Horses No requirement specified (NRS) 2400

Considerations:

  • NRC (2007) recommended dietary vitamin E requirements for horses range from 50 to 80 IU/kg DM
  • exercising horses may require as much as 300 IU/kg DM to maintain vitamin E levels in blood and muscle (McDowell, 2008; Siciliano et al., 1997)
  • NRC (1987) noted most species should tolerate at least 20 times nutritionally adequate levels of vitamin E, and that a presumed upper safe level is 75 IU/kg-BW. With feed intakes ranging up to 3.2% BW, a presumed upper safe level is 2400 IU/kg DM for horses
  • EFSA (2010) indicates that more than 200 IU vitamin E/kg complete feeds are not desirable in feeding practice
  • higher levels of Vitamin E has a potential non-feed/therapeutic use for improving immune function (Petersson et al., 2010)