BERLIN, Oct 25 (Reuters) - The two rival private equity bidders for German online pet supplies retailer Zooplus have teamed up to launch an improved cash offer valuing the target at 3.7 billion euros ($4.3 billion) as they look to tap into a market that has boomed during the pandemic.

Zooplus said on Monday its management and supervisory boards strongly recommended shareholders accept the sweetened offer from Hellman & Friedman and EQT Private Equity, which previously fought a bidding war for the supplier of cat and dog food brands such as Eukanuba, Pedigree and Royal Canin.

The new bid values Zooplus at 480 euros per share, which is 10 euros more than previous separate offers from the two private equity players. That compares with Zooplus's share price of 278.2 euros on the day before Hellman launched its first offer.

The bid battle came after the coronavirus pandemic fuelled a boom in the pet supply industry, with more people buying cats and dogs during lockdowns.

Hellman & Friedman had kicked off the battle for control of Zooplus with a 390 euros per share offer on Aug. 13, a 40% premium to its previous price.

U.S. financial investor KKR had also looked into bidding but dropped the talks two days after Hellman & Friedman raised its offer price on Sept. 12.

Shares in Zooplus were up 0.7% at 479.40 euros by 0715 GMT.

Zooplus said shareholders should accept the offer before it expires on Nov. 3, after which Hellman & Friedman and EQT plan to delist the company if the bid is successful.

"With this offer by H&F in partnership with EQT, our shareholders now have the clarity and ability to take an informed tender decision and realize a remarkable 85 percent premium," said Zooplus chief Cornelius Patt.

Hellman & Friedman will pursue the offer through its investment vehicle Zorro Bidco. EQT plans to become a jointly controlling partner with equal governance rights in a parent of Zorro Bidco following settlement of the deal.

Zooplus said Zorro Bidco had already obtained regulatory clearances allowing for immediate settlement of the offer after reaching the minimum acceptance threshold.

($1 = 0.8593 euros) (Reporting by Zuzanna Szymanska; Editing by Christian Schmollinger and David Holmes)