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 a single product in all brands, or its dosage forms for all species, as a product line. We have approximately 300 comprehensive product lines, including products for both livestock and companion animals across each of our major product categories.

In the fourth quarter of 2019, the company modified the list of major product categories to include a category for dermatology products, which was previously included within other pharmaceutical products. The prior period presentation has been revised to reflect the new product categories.

Our remaining revenue is derived from other non-pharmaceutical product categories, such as nutritionals and agribusiness, as well as products and services in smaller but fast growing areas, including biodevices, genetic tests and precision livestock farming.

Our livestock products primarily help prevent or treat diseases and conditions 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 increased demand for improved nutrition, particularly animal protein. Second, population growth leads to increased natural resource constraints driving a need for enhanced productivity. Finally, as standards of living improve, there is increased focus on food quality and safety.

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, receiving increased medical treatment and benefiting from advances in animal health medicines and vaccines.



	Year Ended December 31,
(MILLIONS OF DOLLARS)	2019		2018		2017
United States	$	3,203	$	2,877	$	2,620
Australia	196		189		176
Brazil	293		295		300
Canada	206		203		184
China	200		211		174
France	117		130		121
Germany	153		147		137
Italy	112		104		89
Japan	158		149		138
Mexico	117		100		86
Spain	114		110		93
United Kingdom	198		181		149
Other developed markets	370		361		339
Other emerging markets	738		710		657
	6,175		5,767		5,263
Contract manufacturing & human health	85		58		44
Total Revenue	$	6,260	$	5,825	$	5,307

Revenue exceeded $100 million in eleven countries outside the U.S. in 2019, ten countries outside the U.S. in 2018 and eight countries outside the U.S. in 2017. The U.S. was the only country to contribute more than 10% of total revenue in each year.



	Year Ended December 31,
(MILLIONS OF DOLLARS)	2019		2018		2017
U.S.
Livestock	$	1,219	$	1,269	$	1,244
Companion animal	1,984		1,608		1,376
	3,203		2,877		2,620
International
Livestock	1,811		1,885		1,793
Companion animal	1,161		1,005		850
	2,972		2,890		2,643
Total
Livestock	3,030		3,154		3,037
Companion animal	3,145		2,613		2,226
Contract manufacturing & human health	85		58		44
Total Revenue	$	6,260	$	5,825	$	5,307



	Year Ended December 31,
(MILLIONS OF DOLLARS)	2019		2018		2017
Livestock:
Cattle	$	1,654	$	1,754	$	1,735
Swine	611		663		621
Poultry	559		522		479
Fish	134		132		118
Other	72		83		84
	3,030		3,154		3,037
Companion Animal:
Horses	195		168		151
Dogs and Cats	2,950		2,445		2,075
	3,145		2,613		2,226
Contract manufacturing & human health	85		58		44
Total Revenue	$	6,260	$	5,825	$	5,307



	Year Ended December 31,
(MILLIONS OF DOLLARS)	2019		2018		2017
Vaccines	$	1,483	$	1,488	$	1,373
Anti-infectives	1,254		1,280		1,253
Parasiticides	966		836		763
Other pharmaceuticals	780		765		753
Dermatology	770		607		428
Medicated feed additives	470		485		475
Animal health diagnostics	268		136		44
Other non-pharmaceuticals	184		170		174
	6,175		5,767		5,263
Contract manufacturing & human health	85		58		44
Total Revenue	$	6,260	$	5,825	$	5,307

We sell our livestock products primarily to veterinarians and livestock producers as well as third-party veterinary distributors, and retail outlets who generally sell the products to livestock producers. We sell our companion animal products primarily to veterinarians who then sell the products to pet

owners. Sales to our largest customer, a U.S. veterinary distributor, represented approximately 15%, 13% and 14% of total revenue for 2019, 2018, and 2017, respectively.