Beef Cattle Browsing – December 2020
Texas A&M Beef Extension November Beef Cattle Browsing
Dr. Joe C. Paschal, Extension Livestock Specialist, Corpus Christi, and Dr. Stephen P. Hammack, Extension Beef Cattle Specialist Emeritus, Stephenville, Editors.
Evaluating Stockmanship in Handling Cattle
A Stockman’s Scorecard was developed to evaluate effects of various techniques used to handle feedyard cattle. The scorecard incorporates 29 handler factors. Observations were made over a 1-yr period of 86 handlers in 39 feedyards, all members of Texas Cattle Feeders Association.
The card includes 30 observation points that create either a positive or negative animal response. These observations are divided into three categories: Situational Awareness (knowledge of the facilities), Herding Skill (knowledge of flight zone and point of balance to move cattle), and Noise/Physical Contact (use of handler’s voice and cattle prods).
Most frequent handling faults and number of handlers committing were:
- fills crowding pen/tub over half-full (n=39);
- slow to remove pressure (n=29);
- uses unnecessary noise (n=25);
- stands in front of animal/taps rear (n=24);
- fails to regulate animal flow through a pinch point (n=22);
- electric prod used as primary driving aid or applied at wrong time (18).
Assessments also were conducted for facilities during scheduled Beef Quality Assurance Feedyard Assessments. Of the 39 feedyards visited, 24 (61%) failed on one or more categories. The most frequent causes of failure were use of electric prods (20%), cattle stumble/tripped when released from the chute (9%), and cattle were miscaught in the head chute and not readjusted (6%). Handlers who scored above average on the Scorecard were subjectively observed to be calm and quiet while working with the cattle. Subjective evaluation of cattle disposition had little effect on Scorecard values.
The authors concluded, “The Scorecard has application as a tool to identify specific stockmanship deficiencies in order to target stockmanship training”.
Editor’s Note: While this study was conducted in feedyards, results should have utility in working cattle, at least yearlings and older, in similar handling facilities.
(Trans. Anim. Sci. 2020:4; West Virginia Univ., Texas Cattle Feeders Association)
Breeding Cows and Heifers on Wheat Pasture
Dr. Glenn Selk, Oklahoma State University Extension Animal Scientist Emeritus, in response to questions on reproductive performance using wheat pasture to grow replacement heifers or add condition to cows before, during, and after the breeding season discussed research conducted at OSU and Kansas State University and reported in 2009 and 2011.
The study included 40 Spring born Angus and Angus cross heifers placed on wheat pasture in December and then randomly assigned to one of two treatment groups in March. The first group (n=20 hd) remained on wheat pasture (avg. CP = 26.6%) through estrus synchronization and fixed time AI. The second group (n=20) were placed in dry lot and had free choice access to a corn-based growing ration (CP = 11.1%) through estrus synchronization and fixed time AI. Both groups were inseminated on or about April 5th of each year. Heifers were exposed to fertile bulls 10 days after AI for 45 days. AI conception was determined by ultrasonography at 32 days.
Heifers developed on wheat pasture were slightly lighter than those in dry lot at AI (867 vs. 897 lb.) but were similar at ultrasound (910 vs. 917 lb.). More wheat pasture heifers were cycling (75%) than dry lot (55%) at the beginning of estrus synchronization, but AI conception rates were similar (53 vs 43%). Final pregnancy rates were also similar for both groups (wheat pasture 95%, dry lot 88%). In this study there was a slight advantage in weight for dry lot but pregnancy rates favored wheat pasture heifers as there was no effect on fertility.
The second study evaluated grazing wheat pasture before and during breeding with first and second calf cows. They compared fixed time AI and final pregnancy rates for cows on wheat and cows on native range for five years. AI pregnancy rates averaged 51.7% and 57.7% for the cows on wheat pasture and rangeland, resp. Final pregnancy rates (using clean up bulls) were similar at 94.4% and 95.9%. Their conclusion was that there was no evidence that the high protein diet of wheat pasture affects pregnancy rate of beef cows.
Editor’s Note: Both of these studies (and others) indicate there is no negative effect of high protein supplementation on reproduction in heifers or cows.
Sire Contribution to Pregnancy Loss in Different Periods of Embryonic and Fetal Development of Beef Cows
Pregnancy loss is a major cause of reproductive failure in cattle. Early embryonic mortality (EEM) is defined as pregnancy losses between the time of insemination (D 0) or embryo transfer (D 7) and 28-30 days of gestation. Late embryonic mortality (LEM) are losses occurring between days 30 and 60 of gestation. EEM, including fertilization failure, which occurs in about 28% of single inseminations in beef cattle, and embryo elongation and maternal recognition of pregnancy. In beef cows, EEM ranges from 34 – 62%, averaging 48%, while LEM ranges from 2 – 10%. About 16% of EEM occurs between D 20 and D 30 of gestation, the embryo implantation period.
Paternal genetics contribute to pregnancy establishment and maintenance, specifically placental formation. A properly formed placenta is required for exchange of nutrients. Pregnancy associated glycoprotein (PAG) are secreted by the placenta and are used in commercial blood tests to determine pregnancy in as early as 28 days. Previous research has shown that PAG levels are influenced by the sire. The objective of this study was to evaluate the effects of service sire on pregnancy loss during different periods of early embryonic development.
Multiparous (n=485) and primiparous (n=173) Angus cows were synchronized using the 7-day Co – Synch + CIDR program and inseminated via timed AI. Females were detected in estrus using Estrotect ® patches. Estrus intensity (not in estrus or low estrus versus high estrus intensity) was determined from patch evaluation score at breeding. Females without a patch were removed from the study.
Cows were randomly inseminated with fertile semen from one of eight Angus sires to assess the sire impact on pregnancy loss. Pregnancy was determined 1) at D 24 by increased circulation of PAG on D 24 compared to D 0, and 2) by ultrasound on D 31 and D 60. After D 60, cows were divided into four groups:
- Pregnant (pregnancy established and maintained until D 60)
- EEM (pregnancy loss between D 24 and 31 of gestation)
- LEM (pregnancy loss between D 31 and 60 of gestation)
- Not pregnant (no elevated PAG at D 24 and no embryo at D 31).
Overall pregnancy rate on D 24 was 54.9% and pregnancy loss (pregnant at D 24 but not pregnant at D 31) was 5.5%. There were no differences due to parity of cow. On D 31 pregnancy rate was 51.8% and pregnancy loss between D 31 and D 60 was 6.7%. Again, there were no differences due to parity of cow.
Pregnancy rates by sire at D 24 were not significantly different and ranged from 47 – 63%. Sires were then classified by percentage of pregnancy loss occurring between D 24 and 31 of gestation. Four sires accounted for 75% of the EEM (High EEM, average loss 8.9%). The other four accounted for the remaining 25% (Low EEM, average loss 2.6%). Cows inseminated with semen from High EEM sires were 3.7 times as likely to have a pregnancy loss between D 24 and 31 of gestation. No differences were observed in PAG levels between the High and Low sires.
Pregnancy rate was similar for all sires at D 31 (44 – 61%) however three sires accounted for 74% of the embryonic mortality between D 31 and 60 of gestation (avg. 11%) while the other five sires accounted for 26% (avg. 3.2%). Once again cows bred to High LEM sires were 3.7 times as likely to experience a pregnancy loss but this time between D 31 and 60 of gestation and again no differences were observed in PAG levels between the High and Low sires.
Estrus expression did influence pregnancy status. Cows that expressed estrus had a significantly higher pregnancy rate at D 24 (63 vs. 48%) but similar pregnancy loss between D 24 and 31 compared to those that did not express estrus (4.3 vs. 6.8%). Moreover, estrus expression had a positive impact on both Low and High EEM sires (17 and 14%, resp.) indicating that exhibiting estrus had a positive impact on reducing EEM.
Cows expressing estrus again had a significantly higher pregnancy rate at D 31 (61 vs. 45%) but similar pregnancy losses between D 31 and 60 (8.3 vs. 6.2%) than those that did not express estrus. However, cows in estrus bred to Low LEM sires had significantly greater increase in pregnancy rate a D 31 (23%) compared to cows in estrus bred to High LEM sires (7%), again indicating the positive effect of estrus on reducing LEM.
Even when bulls pass all standard semen evaluations, there is still much variation in pregnancy rate and pregnancy loss that cannot be explained by visual semen analysis. Since embryonic losses occur over a span of 60 days in this study, an assessment of sire fertility based on a single pregnancy check may not be an accurate assessment. Development of markers to identify sires that are associated with high or low embryonic losses would be beneficial.
Franco, G. et. al. Texas A&M University. Theriogenology 154 (2020) 84-91.
Cost of Pregnancy Loss in Cattle
In a recent multicounty webinar series titled “Show Me the Money”, speakers addressed the topic of value and cost of lost pregnancies. Pregnancy rates determined at pregnancy checks are usually higher than number of calves born. Some of these losses can be attributed to disease or genetics but such losses increase the breakeven price of the remaining calves.
One of the speakers was Stan Bevers, a Texas A&M AgriLife Extension Agricultural Economist Emeritus, who has conducted Standardized Performance Analysis for 350 herds from Texas to Montana. Now as a professional ranching consultant Stan runs Ranch KPI (Key Performance Indicators) https://www.ranchkpi.com/ and is a faculty member with King Ranch Institute of Ranch Management.
Stan reported average annual cow cost of 31 herds in Texas and across the US averaging 1624 head as $956.67. In addition, average pregnancy rate was 90% but calving rate averaged 82.7%, indicating 7.3% pregnancy loss after cows were determined to be safely in calf. Of calves born, 80.2% were weaned (another loss of 2.5% after calving). Average weaning weight of those calves was 561 lbs. and were valued at $161.04/cwt. but the breakeven cost (at weaning) was $207.81.
Stan said that just selling open cows as culls is an expensive and wasteful solution. Open cows do not increase expenses, they remain the about the same. If culled, direct expenses (feed, veterinary, etc.) are reduced but indirect costs (labor, taxes, insurance, repairs, deprecation, etc.) remain the same. When a cow is sold, you are selling a fixed asset. You will have fewer weaned calves to sell and that increases the breakeven of the remaining weaned calves.
Editor’s note: Sales of cull cows (open, old, or less productive cows) represent about 15% of ranch income. Cull cows should be marketed in good condition to maximize weight and price.
Effect of Hay Feeding Method on Cow Performance, Hay Waste, and Wintering Cost
Winter feed costs are a significant portion of costs for most ranchers. A 3-year research project evaluated differences in hay feeding method on cow wintering cost. Bales were either rolled out on the ground, shredded and fed on the ground, or fed in a tapered cone feeder. A total of 360 crossbred cows weighing an average of 1342 lbs. was randomly assigned to one of twelve 4.5-acre traps (3 treatments, 4 replications) during the three years (January – February). Cows were weighed, body condition scored (BCS), and ultrasonically measured for rib fat at the start and end of the 59-d study. Bale weight was recorded and sampled for quality. Alfalfa-bromegrass-crested wheatgrass hay was offered in the first 2 years, oat hay was offered in the third year. Dry matter intake was predicted using NRC formulas. Hay waste was measured.
Cows were fed to maintain or improve their starting body condition prior to calving. There was no interaction between treatment and years (method of feeding or hay type). Cows fed bales unrolled on the ground gained significantly less than cows fed shredded hay in cone feeders. Waste increased amounts of hay fed to the unrolled and shredded hay groups. Hay waste in the cone fed groups was 4.3 to 5 times less than the unrolled or shredded groups. An economic analysis showed that feeding with a tapered cone round bale feeder offered substantial feed cost savings per cow primarily in reduced (5.0 to 15.3%) amount of hay fed to maintain the same body condition of the cows.
Editor’s note: Winter feeding of hay is expensive (about 15% of all cow costs) and feeding methods that are wasteful should be avoided to minimize that loss. Most studies have shown that any form of feeding that keeps cows from walking, lying, or defecating on hay will reduce hay feeding losses and reduce cost.
Landblom, et. al., North Dakota St. Univ. The Professional Animal Scientist (2007) 246-252.
Effect of Weight and Supplementation on Stocker Performance
Crossbred heifers were purchased averaging either 299 lb. or 497 lb. and divided among the two weight groups to be either supplemented once daily over a 45-day study at 1 percent of body weight or not supplemented. Cattle were weighed every 14 days through day 42. Visual hair shedding was visually evaluated on Day 30 as either shed, intermediate shed, or not shed. Cattle were evaluated daily for signs of bovine respiratory disease (BRD). BRD was diagnosed based on visual signs and body temperature higher than 104 F.
Overall, 62% of calves were treated for BRD. Heifers in the lightweight group were 2.8 times more likely to be treated and those that did not shed were 1.6 times more likely to be treated. Initial weight did not affect gain. The supplemented group averaged gaining more than not supplemented. Calves more likely to shed gained more. Calves hauled 200-300 miles to auction gained more than those hauled more than 300 miles. Cattle hauled closer to sale date gained less than those with more time between hauling and sale.
Editor’s Note: Heifers that were heavier (and presumably older) and supplemented gained more during a 45-day post-sale period.
(Proc. 2016 So. Sec ASAS No. 88; Mississippi St. Univ.)
Longevity of Cow Types
Four types of cows were maintained over a lifetime of production: Angus (A), Brahman (B), F1 Brahman X Angus (F1), and F2s created by mating BA bulls X AB females or by mating BA bulls to BA females (F2). Females were culled after failing to wean a calf twice, starting as 2-yr-olds except as 3-yr-olds for Brahman females. Groups were analyzed for percent remaining at 5-yr-of-age, percent remaining at 10-yr-of-age, and average age at removal. Results were:
|Cow Type/Criteria||% at 5-yr-old||% at 10-yr-old||Avg. age at removal|
Editor’s Note: As has been shown in many research studies and observed by commercial producers, F1 Brahman females are superior in numerous production characteristics, including productive longevity. Also, the study documented the predicted reduction in hybrid vigor when F1s are intermated.
(Proc. 2016 So. Sec ASAS No. 4; Texas A&M Univ.)
BQA Tip for December
Dr. Jason Banta, Texas A&M AgriLife Extension Beef Cattle Specialist, Overton
Cubes are often used to supply energy and protein supplementation during the winter. When feeding cubes on the ground it is best to feed cubes in small piles instead of feeding them in a continuous line. Feeding in small piles will reduce waste and fighting. Ideally there would be enough piles for each animal to have it’s own pile. In general, it is best to feed in troughs or at least avoid feeding on gravel or rock roads or pads as this can increase tooth wear and breaking. If feeding in bunks make sure there is adequate space for all cows to eat at the same time.