We offer a diversified portfolio of products which allows us to capitalize on local and regional customer needs. Generally, our products are promoted to veterinarians and livestock producers by our sales organization which includes sales representatives and technical and veterinary operations specialists, and then sold directly by us or through distributors, retailers or e-commerce outlets. The depth of our product portfolio enables us to address the varying needs of customers in different species and geographies. Many of our top-selling product lines are distributed across both of our operating segments, leveraging our R&D operations and manufacturing and supply chain network.

Over the course of our history, we have focused on developing a diverse portfolio of animal health products, including medicines, vaccines and diagnostics, complemented by biodevices, genetic tests and a range of services. We refer to all different brands of a particular product, or its dosage forms for all species, as a product line. We have approximately 300 comprehensive product lines, including products for both companion animals and livestock within each of our major product categories.

•vaccines: biological preparations that help prevent diseases of the respiratory, gastrointestinal and reproductive tracts or induce a specific immune response;

•animal health diagnostics: testing and analysis of blood, urine and other animal samples and related products and services, including point-of-care diagnostic products, instruments and reagents, rapid immunoassay tests, reference laboratory kits and services and blood glucose monitors.

Our remaining revenue is derived from other non-pharmaceutical product categories, such as nutritionals, as well as products and services in biodevices, genetic tests and precision animal health.

Our companion animal products help extend and improve the quality of life for pets; increase convenience and compliance for pet owners; and help veterinarians improve the quality of their care and the efficiency of their businesses. Growth in the companion animal medicines, vaccines and diagnostics sector is driven by economic development, related increases in disposable income and increases in pet ownership and spending on pet care. Companion animals are also living longer, deepening the human-animal bond, receiving increased medical treatment and benefiting from advances in animal health medicine, vaccines and diagnostics.

Our livestock products primarily help prevent or treat diseases and conditions to allow veterinarians and producers to care for their animals and to enable the cost-effective production of safe, high-quality animal protein. Human population growth and increasing standards of living are important long-term growth drivers for our livestock products in three major ways. First, population growth and increasing standards of living drive demand for improved nutrition, particularly through increased consumption of animal protein. Second, population growth leads to greater natural resource constraints driving a need for enhanced productivity. Finally, as standards of living improve and the global chain faces increased scrutiny, there is more focus on food quality, safety, and reliability of supply.

Revenue by geographic area


	Year Ended December 31,
(MILLIONS OF DOLLARS)	2022		2021		2020
United States	$	4,313	$	4,042	$	3,557
Australia	289		259		207
Brazil	330		312		258
Canada	238		232		210
Chile	141		136		100
China	382		357		266
France	126		132		118
Germany	176		183		159
Italy	111		115		90
Japan	173		186		177
Mexico	136		133		116
Spain	118		128		112
United Kingdom	235		234		178
Other developed markets	468		467		388
Other emerging markets	758		778		656
	7,994		7,694		6,592
Contract manufacturing & human health	86		82		83
Total Revenue	$	8,080	$	7,776	$	6,675

Revenue exceeded $100 million in twelve countries outside the U.S. in 2022 and 2021 and eleven countries outside the U.S. in 2020. The U.S. was the only country to contribute more than 10% of total revenue in each year.

Revenue by major species


	Year Ended December 31,
(MILLIONS OF DOLLARS)	2022		2021		2020
U.S.
Companion animal	$	3,341	$	2,990	$	2,391
Livestock	972		1,052		1,166
	4,313		4,042		3,557
International
Companion animal	1,862		1,699		1,261
Livestock	1,819		1,953		1,774
	3,681		3,652		3,035
Total
Companion animal	5,203		4,689		3,652
Livestock	2,791		3,005		2,940
Contract manufacturing & human health	86		82		83
Total Revenue	$	8,080	$	7,776	$	6,675

Revenue by species


	Year Ended December 31,
(MILLIONS OF DOLLARS)	2022		2021		2020
Companion Animal:
Dogs and Cats	$	4,939	$	4,426	$	3,437
Horses	264		263		215
	5,203		4,689		3,652
Livestock:
Cattle	1,440		1,557		1,558
Swine	565		659		621
Poultry	476		507		537
Fish	212		187		148
Sheep and other	98		95		76
	2,791		3,005		2,940
Contract manufacturing & human health	86		82		83
Total Revenue	$	8,080	$	7,776	$	6,675

Revenue by product category


	Year Ended December 31,
(MILLIONS OF DOLLARS)	2022		2021		2020
Parasiticides	$	1,860	$	1,635	$	1,173
Vaccines	1,718		1,673		1,476
Dermatology	1,329		1,180		941
Anti-infectives	1,081		1,215		1,206
Other pharmaceuticals	1,043		966		821
Medicated feed additives	360		420		460
Animal health diagnostics	353		374		305
Other non-pharmaceuticals	250		231		210
	7,994		7,694		6,592
Contract manufacturing & human health	86		82		83
Total Revenue	$	8,080	$	7,776	$	6,675

We primarily sell our companion animal products to veterinarians or to third-party veterinary distributors that typically then sell our products to veterinarians, and in each case, veterinarians then typically sell our products to pet owners. In certain markets, we also sell certain companion animal products through retail and e-commerce outlets. We sell our livestock products primarily to veterinarians and livestock producers, including beef and dairy farmers as well as pork and poultry operations, in addition to third-party veterinary distributors and retail outlets who then typically sell the products to livestock producers. Sales to our largest customer, a U.S. veterinary distributor, represented approximately 14% of total revenue for 2022, 2021 and 2020.