Breeding Drought (Heat) Tolerant Cattle

by Joe C. Paschal

In early August I received a request from the Texas A&M University Department of Animal Science to field some requests for telephone interviews from some radio stations about breeding drought tolerant cattle. One was in San Antonio and the others were regional NPR and CBS affiliates. I had read in the local paper that morning an Associated Press news article out of Des Moines, Iowa entitled “Animals, plants being bred to withstand heat” and there pictured on the front page was my boss, Dr. Ron Gill, looking over his herd of cattle in Wise County, near Boyd, Texas! The article reported on cattle being bred to withstand drought by adding genes from their African (and Indian) cousins who are accustomed to hot weather. It reported that Dr. Gill had incorporated some Beefmaster into his herd and is experimenting with Hotlanders™, a composite developed by the R. A. Brown Ranch in Throckmorton in the 1980s. The Hotlander™ includes Angus/Red Angus, Brahman, Simmental and Senepol (a breed created in the Virgin Islands from crosses of Red Poll from England and N’Dama cattle from Senegal in West Africa almost 200 years ago).

Being an astute guy I put two and two together and realized that the radio interviews were going to be about our breeding drought tolerant cattle, the long history of that in the southern US and, knowing something about Beefmasters (and Hotlanders™ and Senepols), I started making the phone calls. All of those called were polite and the interviews went well (I never heard any on my radio but Dr. Tommy Perkins of Beefmaster Breeders United said the one he listened to did) but it was obvious that all the interviewers were interested in two things – were the cattle researchers doing this because they thought the climate was changing and how were we modifying these cattle genetically?  These questions were never asked directly but I could tell that since the article originated in Iowa and none of the stations had any idea of where Wise County was it was plain that they were wondering why hot climate adapted cattle would be being developed in Iowa. I also emphasized that a hot drought was very different than a cool one and that under no circumstances could any type of beef animal survive a drought unless it had something to eat and drink, no matter how “drought tolerant” it might be!

I started out each interview saying this wasn’t new, that ranchers in the southern US had been using hot climate (not necessarily drought) adapted cattle nearly a hundred years, and that many heat tolerant breeds had been developed within the last 80 years or so and were widely accepted and used in the area. No novel genetic procedures were used except crossbreeding with Bos indicus or Brahman and selection of the crosses for many generations. I also went on to discuss that these cattle, were not only hot climate adapted but had many other attributes to offer over non heat adapted breeds. In addition to being adapted and productive in hot climates these new breeds (Brahman, Santa Gertrudis, Beefmaster, Braford, Brangus, Red Brangus, Simbrah and their crosses) improved beef production across the southern US. The increase in beef production was due to increased resistance or tolerance of internal and external parasites, increased longevity, more durable teeth, higher fertility, improved maternal ability, and faster and more efficient growth of these breeds and crosses in those environments compared to the temperately adapted breeds originally used. Of course this required additional explanations of beef cattle breeding and genetics and the cause and effects of hybrid vigor and were necessary to make the interviewer understand these breeds (including the Hotlander™) were not genetically modified in the sense of the glowing mouse with the jellyfish gene but were carefully bred and selected over generations to provide nutritious beef.

There are a number of breeds around the world adapted to the tropics, the land area between the Tropic of Capricorn and the Tropic of Cancer (or maybe a little further north and south), which represents a significant portion of the Earth suitable for cattle production. These tropically adapted breeds can be divided into two types based on their origin: Bos indicus (probably the greatest number of breeds and the largest number of head) and Bos taurus (cattle in Africa of an intermediate type called “Sanga” and from breeds introduced from Great Britain or continental Europe). Sanga cattle are an intermediate humpless type that probably originated in northeastern Africa over 2,000 years ago and spread south and west. There are numerous African breeds that are included in the Sanga type including Tuli and Africander. Some Sanga cattle, like the Afrikaner, were used in the development of other breeds such as the Bonsmara which was created by Dr. Jan Bonsma in South Africa and is 5/8 Afrikaner and 3/16 Hereford and 3/16 Shorthorn. Some, but not all, of these different tropically adapted breeds have been evaluated by land grant research stations across the southern US and by the USDA Agriculture Research Service in Florida and in Nebraska. The reasons for the interest in these cattle have been primarily for their heat tolerance properties and to see if there are differences between these cattle and the heat tolerant breeds currently used in the US. In most cases the numbers of these cattle are very small and they are not widely used.

Since there were no cattle in the New World, all of the tropically adapted breeds of Central and South America were derived primarily from cattle brought from Spain or from Portugal. Some of the islands in the Caribbean (like the Virgin Islands) were colonized by other countries (like England or Denmark) at some point and their cattle (like the Senepol) influenced by cattle from their homelands. Spain colonized most of the central and South American countries except Brazil which was colonized by Portugal. Spanish cattle were Bos taurus in type and were not tropically adapted (although the Spanish plains can get pretty hot). Portugal had similar cattle but fewer of them, but Portugal also had colonies in India so many of the tropically adapted breeds (Nelore, Indu Brazil, Gyr, etc.), in Brazil owe their origins to the Bos indicus cattle from those Indian colonies. As a result, in Central and South American countries there are many indigenous breeds of tropically adapted cattle of Bos taurus origin as well as Bos indicus. In crossing tropically adapted breeds of Bos taurus origin with nontropically adapted Bos taurus breeds, there is very little or no heterosis or hybrid vigor since the breed origin genetics are too similar.

The main interest in these tropically adapted Bos taurus cattle from either the Western Hemisphere or Africa is to find genetics that convey tropical adaptation without a decline in carcass merit (muscling or cutability but especially high-end marbling) associated with the use of Bos indicus genetics. Most of these breeds are slightly better in crosses for marbling score (Low Select to High Select) but they give up a significant amount of preweaning and postweaning growth. In addition, the breeders of the American breeds of cattle in the US have been selecting their cattle for growth and carcass merit for many generations and most of these new (to the US) tropically adapted breeds have not.  In most cases, like the Hotlander™, those breeds are probably best used in small percentages to convey some hot climate adaptability but used with a healthy dose of other breeds to improve growth and carcass merit.

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