Short answer: Masterfeeds' feeding directions for Rite-Lix 16 AN say "Feed at the rate of one container for every 20 to 30 head." and "Provide a minimum of two (2) containers in each lot or pasture to ensure proper accessibility." On intake, Masterfeeds says "Cattle typically consume between 125 and 500 grams per head daily." Those are the maker's directions for one product, not a ration: ask your veterinarian or a nutritionist to balance your herd's ration.
How many tubs for your herd (our arithmetic)
This is our arithmetic on Masterfeeds' rate of one container per 20 to 30 head, rounded up, with their minimum of two containers in each lot or pasture:
- 20 head: 2 tubs (the two-per-pasture minimum)
- 40 head: 2 tubs
- 60 head: 2 to 3 tubs
- 100 head: 4 to 5 tubs
- 150 head: 5 to 8 tubs
Split across several pastures, each lot or pasture still gets at least two.
How long does a 90.7 kg tub last?
Masterfeeds lists Rite-Lix 16 AN at a net weight of 90.7 kg. On their intake range of 125 to 500 g per head a day, one tub shared by 20 head would last about 36 days at the low end, and one tub shared by 30 head about 6 days at the high end. That is our arithmetic on an average, not a schedule. Masterfeeds says "Free-choice consumption will depend on climate, size of the animals fed, as well as quality, source and availability of other feeds." so check the tubs and watch how fast your cattle take them down.
Where to put the tubs
Masterfeeds' direction: "Place containers in dry spots near loafing areas and watering locations." The Rite-Lix 16 AN directions also say "Masterfeeds 16 AN Block Supplement contains no salt. Provide salt free choice."
For a salt block, the Little Giant MP10 pan is one option: Miller lists it at 18.5 inches square by 5.25 inches high (about 47 × 13 cm, our conversion), holding a standard 50 lb salt or mineral block or 10 quarts (2.5 gallons) of dry material. Miller notes it will not hold water.
Who Rite-Lix 16 AN is for
Masterfeeds describes Rite-Lix 16 AN as "a 16% all natural protein supplement block for cows and calves of all ages, formulated to be fed with good quality forage or pasture." and says it "is for all classes of cattle needing supplemental protein when feeding urea is a concern."
From Masterfeeds' guaranteed analysis: crude protein 16.0% minimum, crude fat 5.0% minimum, crude fibre 2.5% maximum, calcium 1.0% and phosphorus 1.0% (actual), with vitamins A, D3 and E and added selenium at 6.0 mg/kg.
Selenium: read both feed directions before you put out two products
The Rite-Lix 16 AN directions say: "Do not feed in association with another feed containing supplemental Selenium." Masterfeeds' RiteMins Winter page lists "Selenium added at 30mg/kg." So the two Masterfeeds products we list both carry added selenium. Read both sets of directions together, and ask your veterinarian or a nutritionist which one fits your herd before you put out a tub and a loose mineral at the same time.
How much loose mineral: RiteMins Winter
Masterfeeds' direction for RiteMins Winter: "Feed Masterfeeds RiteMins Winter Premix to achieve an intake of 100 grams per head per day as part of a nutritionally balanced feeding program."
Masterfeeds says it is "Primarily intended for feeding to pregnant cows on hay and moderate cereal forage-based winter rations." and to "Feed up until one or two months prior to calving at which time it is recommended switching to RiteMins+ Calving/Breeder Premix."
By our arithmetic on that 100 g rate, a 25 kg bag is 250 head-days of mineral: about 25 days for 10 cows or 5 days for 50 cows. RiteMins Winter contains salt (18% on Masterfeeds' page), and Masterfeeds adds: "If sodium content in the available water source is low, additional supplementation through a salt block is recommended." The RiteMins Winter we list is the regular, non-medicated formula.
Tubs or loose mineral? What the Beef Cattle Research Council says
In its August 2026 article on mineral delivery, the Beef Cattle Research Council (BCRC) sets out pros and cons for each method. On tubs, it says "They require less day-to-day labour compared to loose mineral systems." and that tubs "are often formulated and structured to hold up against rain, snow and wind". Against that: "These products generally come with a higher cost per animal compared to loose mineral." and intake can drift, so it "may fluctuate from the intended target".
On free-choice loose mineral, the BCRC notes that "Dominant cows may guard the feeder, reducing intake opportunities for timid animals, heifers or young cattle." and that "When cattle are offered salt from other sources, they're less motivated to consume free-choice minerals."
The BCRC's own advice is to work with your nutritionist, local extension specialist or veterinarian to decide which delivery method fits your operation.
Cattle supplements and mineral gear we list
- Masterfeeds Rite-Lix 16 AN Supplement Tub - 90.7 kg
- Masterfeeds RiteMins Winter Beef Mineral Premix - 25 kg
- Little Giant 10 Quart salt and mineral block pan - black (MP10)
Cattle on tubs and loose mineral still need open water through the winter: see Heated Water Buckets and Stock Tank De-Icers: Keeping Livestock Water Open Through an Alberta Winter and What Size Stock Tank Do You Need? Tank Sizes vs Daily Water Use. For horses, Masterfeeds' rates are in How Much Senior Feed to Give a Horse? Masterfeeds Rates in Kilograms.
This guide sets out the makers' published directions. It isn't a ration or veterinary advice: read the feed tag on the product you buy, and ask your veterinarian or a nutritionist about your herd.
Sources: Masterfeeds product pages for Rite-Lix 16 AN Block Supplement (product 815003 AN) and RiteMins Winter Premix (product 801331), masterfeeds.com; Miller Manufacturing product page for the 10 Quart Plastic Salt and Mineral Block Pan, miller-mfg.com; Beef Cattle Research Council, "From Tubs to TMR: Pros and Cons of Mineral Delivery Strategies for Beef Cattle" (August 27, 2026), beefresearch.ca. All viewed October 2026.