TEXAS A&M BEEF EXTENSION MARCH BEEF CATTLE BROWSING
Dr. Joe C. Paschal, Extension Livestock Specialist, Corpus Christi, and Dr. Stephen P. Hammack, Extension Beef Cattle Specialist Emeritus, Stephenville, Editors.
WATCH FOR LATENT EFFECTS OF THE FREEZE
A friend and colleague of ours, Dr. Ted McCollum, who was an Extension Beef Cattle Specialist in Amarillo for many years but is now retired to ranching in New Mexico, came up with many of these thoughts after a blizzard hit the Texas Panhandle in late 2015. He reminds us that even after the weather warmed up we should continue to watch our livestock for the aftereffects, especially of this weeklong deep freeze.
The weeklong freezing temperatures and windchill can have especially long-lasting impact on livestock. Tails and ears and even cows’ teats and udders and bulls’ sheaths, prepuces, and scrotums could be frost bitten causing some partial loss (tails, ears, and teats) or loss of function (testes) in the next few days or weeks. These could leave ulcerated sores and should have veterinary care. However, Dr. McCollum said that these were not long-term threats to the animal’s well-being.
Cows with frostbitten udders or frozen teats may be sensitive, reducing milk production and consumption by their calves for a few days. Resumption of nursing could lead to some calf scouring. Also, there might be some mastitis and partial loss of udder function. Cows calving this Spring could also be affected but it would not be noticeable until they calve and begin lactating so they should be evaluated then too.
Prepuces and scrotums of bulls exposed to freezing temperatures and wind chills may have been damaged, especially bulls with slightly larger sheaths and prepuces. Bulls being used now or considered for use should have a breeding soundness examination (BSE) performed on them. Semen production is a long-term process and fertility could be impacted for one or two months.
Many producers lost calves since the weeklong freeze occurred during calving season and some have reported stillbirths of near-term calves. This seemed to be most prevalent in high percentage Bos indicus calves. Dr. Ky Pohler, Reproductive Physiologist in Animal Science at A&M said he has observed early pregnancy losses due to the physiological stress of the extreme cold. Usually, he said cattle can tolerate this type of stress, but this was unusual and long in duration.
Dr. Tom Hairgrove, Extension Food Animal Veterinarian said that cattle could have an outbreak of internal parasites as a result of the long-term stress and that young cattle and calves fed in or on wet hay could experience coccidiosis. He advises to be on the lookout for black or bloody scours in calves.
Bulls for breeding for fall calving herds should have a Breeding Soundness Exam (BSE) performed as soon as possible to check for injury and semen quality to ensure a high percent calf crop. Cows in fall calving herds that are not bred could have delayed estrus and pregnancy resulting in late calves. Estrus activity should return to normal in a few weeks if there are no other injuries.
Cattle and other livestock that survived the extremely frigid temperatures for days are physically very stressed, even those that were adequately supplemented and sheltered. Producers should monitor their herd’s body condition scores and possibly increase supplemental feeding for the remainder of breeding season (for fall calving cows) or calving (for spring calving cows). Finally, observe your livestock closely for other signs that, even though they survived the weather, something just is not quite right.
HOW DO PLANT-BASED ALTERNATIVES AFFECT DEMAND FOR BEEF?
Plant-based alternatives are chosen by some consumers in place of beef. A survey was conducted in September 2020, of over 3,000 consumers, weighted to be representative of the U. S. population. Plant-based protein products were compared to beef. Lab-based protein alternatives are being developed but are not currently marketed, so they were not included in the study. Highlights of results were as follows:
– Beef is chosen about three times more than plant-based.
– Consumers’ perceptions of taste, appearance, price, naturalness, protein, and iron of beef greatly exceeds that for plant-based proteins.
– Plant-based had high perceptions for the environment, health, and animal welfare, but still were ranked slightly lower than beef for those factors.
– Cholesterol, fat, and fiber were ranked higher for plant-based products and these are major reasons some consumers purchase such items.
– Nutrient content on labels did not significantly affect purchase of either beef or plant-based burgers.
– Typical regular meat consumers in a restaurant would pay $1.87 more for a beef burger than a Beyond Meat burger. Vegans, vegetarians, and flexitarians (those primarily consuming plant-based foods but with some animal products in moderation) would pay $1.48 more for Beyond Meat.
– But at retail, typical meat consumers would pay only $0.29/lb more for store-brand 80% lean ground beef over Beyond Meat; those with preferences for alternative diets would pay at retail $2.32/lb more for Beyond Meat.
– At retail under contemporary pricing, only about 2% of regular meat consumers would choose Beyond Meat or Impossible burger.
– At food-service sources, only 5% of regular meat consumers would choose Beyond Meat burgers over beef.
– Consumers selecting Beyond Meat products were more likely to be younger, have children at home younger than 12, have higher income, live in a Western state, have a college education, and be affiliated with the Democratic party.
– Changes in price of beef have much more effect on decisions to buy beef than do changes in price of plant-based product, so plant-based burgers are relatively weak substitutes for beef.
The authors noted the following:
– If prices of plant-based products decrease, regular beef consumers would become more likely to purchase such products.
– Emphasis should continue on the positive characteristics attributed by consumers to beef.
– Relative price of chicken breast is much more important in affecting demand for beef than is price of plant-based products.
– Improvement in taste and appearance of plant-based products would make them more competitive with beef.
– The beef industry should concentrate on improving overall size of the market and developing ways to improve profitability of beef producers.
Source: Kansas St. Univ., Jan 17, 2021. Full report here. (https://agmanager.info/livestock-meat/meat-demand/meat-demand-research-studies/impact-new-plant-based-protein-0)
BROWN FAT ENSURES SURVIVAL IN CALVES
Why do some calves survive the rigors of being born in cold, wet weather while others in the same situation die of hypothermia? Also called brown adipose tissue (BAT), brown fat’s function is to generate body heat by nonshivering thermogenesis.
BAT is tucked between the shoulder blades and covers the heart, kidneys, and major blood vessels. Stephen B. Smith, Ph.D., Regent’s Professor of Meat Science at Texas A&M University, says he considers this specialized fat to be an organ because it has a blood supply and a specific purpose. Vast amounts of mitochondria, the energy-producing structures in cells, give BAT a unique reddish-brown color.
“If calving occurs in winter or a cold spring, BAT generates heat by a process known as nonshivering thermogenesis, using fatty acids,” Smith explains. “BAT provides additional protection for the internal organs. The function of BAT is to keep the newborn alive if it is born in a very cold environment.”
This system warms the blood, which spreads heat throughout the body. Temperatures below 50ºF kickstart the heat-generating properties of BAT. BAT deposits decline within a month; the remnant changes into white adipose tissue (WAT) as large numbers of energy-producing mitochondria disappear.
“The fact that all adipose tissue starts prenatally as BAT rather than as WAT and that it’s located around the internal organs indicates this is an important mechanism for survival,” Smith reveals. If calves are born during warm temperatures of 50ºF and above, there is no signal for BAT to generate heat. In this scenario, BAT differentiates to become WAT, which can be used later by the animal if there is a nutrient shortage.
One of Smith’s research projects examined Angus-Wagyu cows. One set of dams received restricted protein; another received recommended amounts of protein. Limiting the dam’s protein did not appear to affect the neonatal calf’s BAT function or calf weight. The cow sacrificed her internal energy source and muscle for her calf’s survival. However, more calves from thin mothers fail to survive cold, wet conditions than those from well-nourished dams.
“Anything producers can do to maintain good nutrition for the cow will result in a healthier calf,” Smith advises. “It just makes sense that if the cow is well fed, the calf will be healthier and have more BAT.” Some cattle breeds, including Hereford and Angus (Bos taurus) have more BAT than Brahman cattle, with Bos indicus genetics. Brahman calves do not survive well in cold climates. Research shows that Brahman and Angus calves maintain identical lipid amounts in warm temperatures.
However, marked differences appeared when researchers moved calves to cold chambers. The calf’s sympathetic nervous system detected cold, starting the sequence of events for BAT function. Angus calves maintained their BAT lipid supplies, while non-shivering thermogenesis kept them warm. Conversely, Brahman calves placed in cold chambers had little lipid remaining after 48 hours, running out of “fuel.” Smith compares this difference in metabolism to a Maserati sports car and Ford sedan. The Brahman or Maserati races through fuel, but the Angus or Ford utilizes energy more efficiently, traveling longer on one tank of fuel.
Brahman cattle do well in most of India’s rare short-term chilly spells; however, they have not adapted to withstand prolonged frigid temperatures. As a result, these calves’ blast through their energy supplies to stay warm. They thrive in warmer regions, such as Southwestern or Gulf Coast states. Some experts believe calves with good BAT stores survive the labor and birthing process easier. “If the dam received a quality diet, the calf will have adequate BAT supplies and will be a healthier calf,” Smith advises. “Steer away from the Bos indicus influence if these calves will be born in cold environments. Ranchers could have serious calf loss, affecting the bottom line.”
Shawn Archibeque, Ph.D., ruminant nutritionist at Colorado State University, says the immature nervous system of neonatal animals cannot start a shivering response. The shivering thermogenesis mechanism forces skeletal muscles to constrict and expand, which generates heat. The newborn’s ability to dry off, warm up and raise its core temperature during wintry weather depends on how much stored body fat is available. Neonatal calves must rely on BAT to fuel non-shivering thermogenesis during the first few days of life.
“I was surprised by how strikingly different BAT is, from how it functions at a metabolic level to how it appears,” Archibeque admits. “Its [brown color] is really distinct. This unique mechanism doesn’t last long. Just long enough to help that young calf until it’s able to shiver and generate heat to maintain its body temperature.”
A primary benefit of BAT allows young animals to stay warm, particularly in colder climates. Archibeque says if they are born in south Texas, it is not a big deal. If they are born in late February to early March in Colorado, BAT is critical for survival. “The point of this system is to metabolize fat and run all the biochemistry,” Archibeque observes. “Instead of generating adenosine triphosphate [ATP], which is the energy currency of the cell, it lets it go. Uncaptured energy becomes heat. Calves burn a lot of fat quickly to create heat. From a production standpoint, that will not be sustainable in the long run.”
Archibeque advises producers to make sure they are not limiting their cows’ intake during the third trimester. That is the time to consider supplementation programs. It could be as simple as providing a product that stimulates greater intake of available forage or one that has non-protein nitrogen, which increases digestibility of consumed forages. It also encourages eating more hay than normal. The cow will have more energy and protein which helps support the fetus’s growth and develop BAT deposits.
Good mothers make a difference, but research shows that calves’ survival depends importantly on brown fat.
Editor’s Note: BAT was discovered over 100 years ago in hibernating animals where it plays an important role in sustaining metabolism of those animals. BAT is highest in young animals and is highest in animals born in colder climates.
EFFECT OF SELECTING HEIFERS FOR CALVING EASE ON BODY SIZE AND REPRODUCTION
Calving ease is an important consideration for cowherds, especially in first-calf heifers. Heifers from 7 breed-types were selected (SELECT) either for reduced Calving Difficulty Expected Progeny Difference (EPD) or average Birth Weight EPD (CONTROL), and also for identical Yearling Weight EPD. Heifers were culled for once being open and for health problems but not for other factors. Both groups were bred to the same bulls.
SELECT heifers were statistically different at birth (6 lb. lighter) but not at weaning (0.4 lb. lighter) or yearling (4 lb. lighter). At maturity, SELECT were 72 lb. lighter (predicted from the generally recognized Brody growth curves) and 1.2 inches (0.6 Beef Improvement Federation Frame Scores) lower in hip height.
SELECT heifers had significantly decreased calving assistance (16% vs. 39%) and higher calf survival (87% vs. 71%). Assistance and survival did not differ after first calving. Calf weaning weights were not significantly different.
NOTE: Based on these results, selecting heifers on reduced Calving Ease EPD would reduce percentage of heifers requiring assistance at birth and increase calf survival. Based on predicted mature weight, selected heifers should have lower mature nutritional requirements. But they still would wean as much calf weight.
(J. Animal Sci. 98 Supple. 4 p. 22; U. S. Meat Animal Res. Ctr.)
DOES FEED EFFICIENCY AFFECT OTHER PRODUCTION TRAITS?
Feed efficiency is an important production and economic trait. Efficiency once was commonly calculated as feed conversion, the ratio of feed (nutrients) consumed to weight produced (feed:weight), or the reverse of feed efficiency (weight:feed). Weight:feed has the benefit of larger numbers being desirable. In recent times, another measure of efficiency has been proposed, Residual Feed Intake (RFI).
RFI is the difference between an animal’s actual feed intake above or below that expected or predicted on the basis of its size and growth. RFI is independent of an animal’s level of production, such as rate of gain. Residual Average Daily Gain (RADG) also is used in some cases. RADG also has the advantage of higher values equaling higher efficiency. In RFI, lower value equals higher efficiency. RFI and RADG were the subject the subject of four recent research reports.
Over two years, non-lactating cows ranging from 1 to 9 years of age were grazed for 84 days on dormant native range from mid-October to early January. Effects were measured of RFI on changes in body weight and body condition (evaluated by visual Body Condition Score, BCS). A subgroup of cows, stratified by age, was fitted with GPS collars to measure RFI. Cow age influenced supplement intake, change in body weight, and BCS. But, within age groups, there was no statistically significant effect of RFI on changes in body weight or BCS.
(J. Anim. Sci. 98 No.1 Supple. 4, p. 208; Montana St. Univ.)
Angus heifers were weaned, grown for 45 days, and then fed a forage-based ration for72 days with daily individual feed intake measured. RFI was calculated. When ready for breeding, heifers were synchronized for artificial insemination. Pregnancy was determined six months after AI. Feed intake, ADG, and RFI did not significantly affect response to synchronization, first service conception, or pregnancy rate. The authors conclusion was heifers “can be selected for low RFI (more efficiency) to decrease feed costs without compromising reproductive performance”.
(J. Anim. Sci. 98, Supple. 4, p. 476; Calif. St. Univ. Univ. Chico)
Bos taurus and Bos indicus influenced heifers were fed for 70 days to assess feed efficiency. After feeding, heifers were classified into Low, Medium, and High RFI groups. Feed:gain was statistically highest for Low RFI vs. High and Low vs. Medium. Significantly more Low than High heifers cycled before start of breeding. Low and Medium had significantly younger age at puberty than High. Bos taurus were significantly younger at puberty, by 14 days. The authors concluded “selection of heifers for feed efficiency (low RFI) may positively impact reproductive performance of replacement heifers”.
(J. Anim. Sci.98: Issue 10; Univ. Of Florida, Univ. of Georgia, Montana St. Univ., Virginia Tech Univ.)
A group of Angus and Red Angus bulls was fed for three months. Individual feed consumption was measured. RFI and RADG was calculated. Bulls were classified into low, marginal, and high RFI groups. Breeding Soundness Exams were conducted at 18 months of age. High and marginal RFI groups consumed more feed. There were no statistically significant differences among RFI groups in RADG, scrotal circumference, sperm motility, or sperm morphology.
(J, Anim. Sci. 98, Supple. 4, p. 474; Calif. St. Univ. Chico.)
NOTE: Overall, these studies indicate that selection of heifer replacements for feed efficiency (based on RFI) did not adversely affect reproductive factors and should reduce cow nutritional requirements. Also, RFI was not related to factors involved in Breeding Soundness Exam in young bulls.
BQA Tip for March
Dr. Jason Banta, Texas A&M AgriLife Extension Beef Cattle Specialist, Overton
Estrus synchronization is used by some cattle producers to facilitate artificial insemination, embryo transfer, and natural breeding. Various products including GnRH, prostaglandin, or analogues of these hormones are used in synchronization protocols. It is critical to read the label for each product to make sure it is stored and administered according to label directions. Products that are used for the same purpose vary in storage guidelines. Some should be stored at room temperature and others in a refrigerator. Use a refrigerator thermometer to monitor the refrigerator temperature. Unless the label states otherwise, these products should be administered in the neck according to BQA best management practices.