Zoetis supplements see FDA approval for combined use

The US Food and Drug Administration (FDA) said the US animal health company’s ractopamine hydrochloride supplements – Actogain 45 for cattle and Engain for swine – can be used in conjunction with other additives.

“All feed additives have to be approved by the FDA, and when you want to feed one in combination with another that combination also needs to be approved,”​ Marilyn Corbin, veterinarian and member of the beef technical services team at Zoetis, told FeedNavigator.

Combination benefits​

Ractopamine is used in both cattle and swine to increase weight gain, feed efficiency and carcass leanness, said Zoetis researchers.

In swine, the supplement can be used in the last several weeks, said Daniel Nelson, Zoetis nutritionist and pork technical services member. But when used with the now approved, additional additives producers also can also prevent diseases like swine dysentery.

Similarly, in cattle, the ractopamine additive could now be used to boost weight gain and, in combination with products, to control problems like liver abscesses, Corbin added.

Approval details ​

The approvals apply to generic versions of the drugs, Corbin said. Though they have brand names for marketing purposes they aren’t the “pioneering product.”​ 

Additionally, they have been approved for use with named, but generic versions of other additives, she said. “Before you had to use the branded product – now you can use Tylan or Tylovet,”​ she added. Both are forms of tylosin phosphate.

The ractopamine feed supplement for finishing swine has been approved for use with tylosin phosphate, said the FDA.

The intended use of the combination includes improved feed efficiency, weight gain and a leaner carcass along with treatment for swine dysentery or the management of porcine proliferative enteropathies, the agency said.

Depending on the desired effect, the additives may be fed at different levels, said the agency.

These include from 4.5 to 9 g/ton ractopamine and 40 to 100 g/ton tylosin phosphate lasting two to six weeks with the use of 250 mg of tylosin tartrate; ractopamine at 4.5 to 9 g/ton and tylosin phosphate at 100 g/ton for three weeks then at 40 g/ton; and ractopamine at 4.5 to 9 g/ton and tylosin phosphate at 100 g/ton for 21 days.

Additionally, the cattle feed supplement received two combination approvals.

The ractopamine hydrochloride additive can be used in conjunction with either monensin USP and tylosin phosphate, or it can be combined with use of monensin USP, tylosin phosphate and melengestrol acetate.

In the first combination, the supplements can be used for weight gain and feed efficiency as well as to prevent or control coccidiosis caused by Eimeria bovis​ and E. zuernii ​and to limit liver damage from Fusobacterium necrophorum​ and Arcanobacterium pyogenes​, said the FDA.

The second supplement combination can be fed to heifers for the final 28 to 42 days and for the additional purpose of suppressing estrus, said the US agency.

Market response and expansion​

“We did have customers requesting that we get this approval,”​ said Corbin. “These mirror approvals for the pioneering brands.”​ The company went through the process because of those requests, she added.

The approved combinations also are being offered as a way for the company to meet the needs of customers as new rules regarding use of certain antibiotics take effect, Corbin said.

She said that, although the combinations are not designed or intended to replace antibiotic use, they do allow for customers to use either the original or generic versions of the antimicrobial tylosin phosphate with the ractopamine supplement, while following the new guidelines.

“It ties into stewardship messaging – we’re making sure that we offer products in appropriate combinations,”​ she said.