In a Montana State University trial, spring-born steer calves were early weaned at about 74 days of age. They were then assigned to two different dietary treatments — a high-starch diet of 60% barley, or a high-fiber diet of 60% wheat middlings. The diets were equivalent in crude protein and net energy.
At weaning, all calves were weighed and ultrasounded to determine intramuscular fat (IMF). Ultrasound measurements were repeated every 28 days until the steers were shipped to a commercial feedyard at 90 days after weaning. Steers were harvested at 307 ±7 days after weaning (about 12.5 months of age).
Average daily gain was greater during the first 34 days post-weaning for barley-fed calves than for wheat midd-fed calves (2.84 vs. 2.18 lbs./day), but gains were similar for the entire 90-day growing period (avg. of 2.81 lbs./day). Barley-fed calves deposited significantly more IMF early and retained this advantage until shipment to the feedyard (4.44% vs. 3.31%). However, by time of harvest, there was no significant IMF difference between treatments. (Rainey et al. 2003. Montana State University Beef Newsletter, Vol. 9, No. 1, Dec. 2003).
— Michigan State University Beef Cattle Research Update, Winter 2004
Fed at similar levels of organic matter (OM), soybean hull supplementation provided an average of 6% greater digestible OM intake than corn supplementation, University of Kentucky (UK) researchers concluded.
Cattle consuming only forage are often unable to meet desired production levels. Research has been done to determine optimal supplementation strategies under various conditions. This includes feeding starched-based supplements, such as cereal grains vs. energy supplements high in digestible fiber, like soybean hulls.
UK researchers recently focused on the effects of tall fescue hay maturity on intake, digestion and ruminal fermentation responses to different supplemental energy sources fed to steers.
Twelve steers were split into three supplemental treatments — no supplement, pelleted soybean hulls and coarse-cracked corn. The second factor was the maturity of the fescue hay — vegetative, boot-stage, heading-stage or mature. The supplements were fed twice daily at 0.67% of the steers' body weights. Tall fescue hay was offered at 150% of average intake.
Compared with the soybean hulls, corn supplementation resulted in greater negative associative effects on OM digestibility.
J. Anim. Sci., Jan. 2004. 82:307-318
Colorado State University and University of Nebraska scientists analyzed data from a large Nebraska cow herd to compare three economic models to determine optimal replacement and marketing strategies for maximizing long-term profit potential. The model that consistently returned the highest average net income per animal annually for the enterprise also had the most distinct and visible composition over a 20-year period with respect to cow age groups (yearlings, 2s, 3s, 4 to 9s, and over 9s).
This model suggested the ranch should market mostly weaned heifers in lower-priced years and mostly bred yearlings in higher-priced years. This results in an older herd in lower-priced years and a younger herd in higher-priced years. The model also favored selling more cows as bred cows in the fall than as pairs in the spring.
The authors acknowledged that a replacement strategy for different ranches may vary with differing circumstances. As a result, this decision should be repeatedly addressed to ensure the long-term success of the enterprise. (Mackey et al. 2004. Prof. Anim. Sci. 20:87).
— Michigan State University Beef Cattle Research Update, Spring 2004
Producers can be confident sexing sperm won't increase abnormalities or affect calf characteristics, say Colorado State researchers.
The sexing process can damage sperms' motility, viability and membrane integrity. Physical stress during sorting can also do physical damage to the membrane. No increases in calf abnormalities with sexed sperm have been reported, but there are indications that early embryonic mortality may be increased slightly.
Researchers studied the characteristics of calves to determine if there are differences between calves from sexed sperm vs. unsexed sperm.
Data was collected from 1,169 calves produced from sexed sperm and 793 calves in the control group. Researchers analyzed gestation length, birth weight, abortion rate, calving ease, weaning weight, calf vigor, and death rate (neonatal through weaning). There was no significant difference between the two groups, and calves born from sexed sperm grew and developed normally both pre- and post-natal.
The sex ratio at birth from unsexed control sperm was 49.2% male. Sexing accuracy from X-sorted sperm was 87.8% female calves, and Y-sorted sperm produced 92.1% male calves.
J. Anim. Sci., April 2004. 82:1029-1036