High pressure heat domes and beef cattle
by Glenn Selk, Emeritus Extension Animal Scientist and the late Dr. Dave Sparks, OSU Area Extension veterinarian
During the very hot, dry summer of 2011, the late Dr. Dave Sparks, Oklahoma State University Extension Veterinarian, wrote a very comprehensive article about heat stress in cattle and livestock in general. Dr. Sparks’ understanding of heat stress came from years of veterinary practice in Southern Kansas and as Extension Veterinarian in Eastern Oklahoma. His thoughts seem applicable nearly every summer in Oklahoma. The following are some key excerpts from that article:
“Unlike horses and humans, cattle, sheep, goats, and pigs do not sweat, at least not in amounts sufficient to be beneficial for body cooling. They maintain their body temperature at or near a constant, normal, level by panting. This moves air across the highly vascular and moist mucous membranes of the mouth, tongue, and nasal passages, thus cooling the blood passing through these tissues much like the water in an engine is cooled as it passes through the radiator. For this to occur, they need a lower environmental humidity and adequate water for evaporation on the surface of the membranes. If livestock are not able to maintain their normal body temperature they start to show signs of reproductive compromise first, followed by heat exhaustion at about 105 F, and cell breakdown and death at about 107 F.
In extremely hot weather it is normal for body temperatures to rise moderately above normal during the heat of the day and to cool off at night when environmental temperatures are less. It takes several hours, however for this to occur. Although air temperatures often decline in the late afternoon or evening the animal’s body temperature may not fully recover its normal level until 2 or 3 o’clock in the morning after several hours of cooler temperatures. Because of this, taking the temperature to determine if an animal is sick is best done early in the morning to get a true indication. If you must “work” or handle livestock during hot weather, do it as early as possible in the morning and be finished before their body temperature starts to rise…..”
“In hot weather the first thing to suffer in your herd is reproductive efficiency. Reproductive problems can range from poor fertility to no fertility. In some males high core body temperature causes suppression of libido, but that is only the beginning of the problems. In male mammals the testicles cannot produce or maintain sperm cells at body temperature. The scrotum is designed to keep the testicles several degrees cooler than the body’s core temperature by means of special muscles that lower the testicles away from the body as air temperature rises and pull them back closer as air temperature decreases. Also, the pampiniform plexus is a heat exchange unit that cools the blood entering the testicles. When these mechanisms are overcome by the environmental temperature problems occur. Sperm cell formation, or spermatogenesis, starts to decrease when the testicular temperature rises as little as 1/2 degree and sperm cells start to die if the testicular temperature rises as much as 2 degrees above optimum. This can be significant because if extremely hot weather causes the death or deformation of sperm in the male system it can take as long as 6 weeks for new cells to be formed and mature. This can result in a temporary sterility. Research has shown that in females, high body temperatures can result in lowered conception rates and embryonic death. Excessive heat affects embryo survival and fetal development most markedly during the first 21 to 30 days after breeding….”
Dr. Sparks understood that breeding seasons in the Southern Plains must be planned so as to avoid the mid to late summer time frame when high pressure heat domes tend to reside over this area of the United States.
Cattle and beef production in China
by Derrell S. Peel, Oklahoma State University Extension livestock marketing specialist
According to estimates from the USDA Foreign Agricultural Service, China is the fourth largest beef producing country in the world behind the U.S., Brazil and the European Union. 2018 Chinese beef production is estimated at 7.3 million metric tons, 58 percent of projected U.S. beef production of 12.4 million metric tons. China has an estimated total cattle herd of 96.85 million head in 2018, slightly larger than the current U.S. herd of 94.4 million head.
In May and June, I met with cattle and meat industry experts in China with the assistance of the U.S. Meat Export Federation offices in Beijing and Shanghai. A cattle industry expert in Beijing provided an excellent summary of cattle production in China. The bulk of cattle production consists of an assortment of native beef breeds, known collectively as Yellow cattle, concentrated in the North China Plain, the northeast and the extensive grazing lands of the northwest. The Chinese cattle industry also includes yak production on the high Tibet plateau in the southwest and water buffalo production in the south and southeast.
The central region of the North China Plain is the largest beef production region and includes the provinces of Henan, Hubei, Hunan, Shandong, and Jiangxi and surrounding regions. I traveled across these provinces and yet saw very few cattle. Cattle production takes place in and around intensive crop production, utilizing a diverse set of crop residues and residual forage from roadsides, ditch banks, farmsteads, etc. One does not see big herds of cattle grazing large pastures. Most producers in this region usually own less than 10 head of cattle with perhaps 2-5 cows. Larger cow herds of up to several hundred head can be found in the grazing lands of northwest China. Productivity is relatively low with cows typically producing two calves every three years. Though dual-purpose production was once more common, dairy production has specialized and most beef production today is solely for meat.
Yellow cattle account for roughly 70 percent of beef production with a small, but growing, use of European breeds in place of native cattle; crossbreeding of Yellow cattle and imported breeds; and development of composite breeds of Yellow cattle and European breeds. In mountainous areas, the moderately-sized Yellow cattle are better adapted and remain the predominant cattle type. Weaned calves move into larger growing and finishing operations. Roughly 60 percent of cattle are finished using corn-based rations in feedlots that range in capacity from a few hundred to a few thousand head; with the largest feedlots up to 20,000 head.
Beef production in China today continues mostly with traditional systems used for many years. The beef industry has so far received relatively little attention from the Chinese government compared to pork, poultry and dairy, where large investments in modern, large-scale production facilities are rapidly changing and increasing production. It appears that Chinese cattle and beef production has potential to be significantly enhanced with complementary use of different genetics, improved management and larger-scale production systems.
However, increased beef production in China will face challenges. Beef production has the greatest potential to expand in the major agricultural regions of central China, where use of resources for cattle production will compete with increasing demand for crops and other agricultural production to meet relentlessly growing food demand in China. The drier, extensive grazing areas of the west and northwest face less competition from other agricultural production but are inherently limited by climate and productivity of the land and suffer from degradation of some grazing areas. Exactly how much and how fast beef production in China will grow will depend on beef demand in the country. The next article will look at beef consumption and rapidly growing beef imports in China.
July cattle on feed and mid-year cattle inventory
by Derrell S. Peel, Oklahoma State University Extension Livestock Marketing Specialist
The July Cattle report confirms larger cattle inventories in 2018. The total U.S. cattle herd was reported at 103.2 million head, up 1.0 percent from last year and the largest July 1 inventory since 2008. The July 1 beef cow inventory is 32.5 million head, up 0.9 percent compared to one year ago. Beef replacement heifers were down 2.1 percent year over year at 4.6 million head. Dairy cow and dairy replacement heifer inventories were unchanged year over year. The 2018 calf crop was estimated at 36.5 million head, up 1.9 percent over the 2017 calf crop. The combined inventory of steers, other heifers and calves, adjusted for cattle on feed, leads to an estimated July 1 feeder supply of 37.1 million, up 0.5 percent year over year. Cattle supplies will continue to grow, but slower, through 2019 at least.
The July Cattle on Feed report fell right in line with average industry pre-report estimates. June placements were 101.3 percent of one year ago, the largest June placement total since 2006. June feedlot marketings were 100.9 percent of last year, the largest June marketing total since 2011. June 2018 had one less business day compared to 2017. The July 1 on-feed total was 11.282 million head, up 4.3 percent year over year.
The July 1 quarterly inventory of heifers in feedlots was up 7.7 percent from last year, a large enough value to suggest further slowing in heifer retention but down compared to the double-digit year over year increases of the previous four quarters. Steers in feedlots on July 1 were up 2.4 percent year over year.
The modest increase in beef cows, combined with a smaller inventory of beef replacement heifers, suggests that herd expansion is slowing even more in 2018 after slowing in 2017. However, the ratio of July 1 to Jan. 1 beef cow inventory is 102.4, a level that historically implies positive herd expansion in the current year. The ratio is down from 2015 and 2017 levels (No 2016 July Cattle report was issued), again indicating slow expansion for the current year and perhaps a peak in the cow herd inventory in 2019.