Field Evaluations of Insecticide Modes of Action Classes for Control of Horn Flies in Nebraska

Insecticides of different Mode of Action (MoA) classes were tested for their ability to reduce horn fly populations on cattle in Nebraska pastures between 2009 and 2016. Macrocyclic lactone products were the most efficacious, reducing horn fly numbers by an average of 93% over ten location years of testing. Organophosphate and pyrethroid MoA products, tested in 7 and 12 location years, reduced fly numbers by 75% and 73%. Classes tested only once were METI (88% reduction) and a combination of organophosphate + pyrethroid (64%)

Impact of Cow Size on Cow-Calf and Subsequent Steer Feedlot Performance

This study retrospectively evaluated the effect of cow size on cow-calf performance and post-weaning steer feedlot performance of cows at the Gudmundsen Sandhills Laboratory, Whitman. Cows were categorized at small, medium, or moderate within cow age from 13 years of data. Small cows had decreased reproductive performance, weaned smaller calves, and produced steer progeny with smaller carcass weights. In this dataset and under the environmental and management conditions at Gudmundsen Sandhills Laboratory, overall productivity of the cowherd decreased as cow size decreased with 1,150 to 1,200 lb cow being the most productive cow size

The Effect of Cow Udder Score on Subsequent Calf Performance in the Nebraska Sandhills

Cow records were evaluated over a 5-yr period to investigate how cow udder score affected calf growth and carcass performance. Cows from 2 calving herds, March and May, were classified as bad or good based on udder scores recorded at calving. Calves suckling dams with bad udders performed similarly during the pre-weaning period to good udder counterparts, with no differences in overall steer feedlot performance between udder groups. However, steers suckling good udder cows had heavier carcass weights and greater back fat thickness

Evaluating camera trapping as a method for estimating cheetah abundance in ranching areas

In order to accurately assess the status of the cheetah Acinonyx jubatus it is necessary to obtain data on numbers and demographic trends. However, cheetahs are notoriously difficult to survey because they occur at very low population densities and are often shy and elusive. In South Africa the problem is further complicated in areas where land is privately owned, restricting access, with dense bush and cheetahs that are frequently persecuted. Cheetahs are individually identifiable by their unique spot patterns, making them ideal candidates for capture-recapture surveys. Photographs of cheetahs were obtained using four camera traps placed successively at a total of 12 trap locations in areas of known cheetah activity within a 300 km2 area in the Thabazimbi district of the Limpopo Province. During 10 trapping periods, five different cheetahs were photographed. These results were used to generate capture histories for each cheetah and the data were analysed using the capture-recapture software package CAPTURE. Closure tests indicated that the population was closed (P = 0.056). The Mh model was used to deal with possible heterogeneous capture probabilities among individual cheetahs. Closure tests did not reject the model assumption of population closure (P = 0.056). The Mh model produced a capture probability of 0.17 with an estimate of 6-14 cheetahs (P = 0.95) and a mean population size of seven cheetahs (S.E. = 1.93). These results are promising and will be improved with employment of more camera traps and sampling a larger area

Impacts of 40 Years of the Gudmundsen Sandhills Laboratory on Beef Cattle and Range Systems

The University of Nebraska (UNL) Gudmundsen Sandhills Laboratory (GSL) is a 12,800-acre research ranch in the Nebraska Sandhills. In 1978, Elmer “Pete” and Abbie Gudmundsen gifted the former Rafter C Ranch to the University of Nebraska Foundation. Thus, 2018 was the 40th year of UNL oversight of GSL. To the credit of UNL Administration, GSL development for range livestock research was delegated to a team of Research and Extension Specialists chaired by Dr. Don Clanton. Other members of that original team were Jim Nichols, Range Science; Gene Deutscher, Reproductive Physiologist; Dick Clark, Agricultural Economist; and Ivan Rush, Beef Extension Specialist. This team configured the ranch to investigate production and management questions pertinent to the region

EC07-281 Body Condition Scoring Beef Cows: A Tool for Managing the Nutrition Program for Beef Herds

This 2007 Extension Circular describes the nine-point body condition scoring system, relationship between body condition and the productivity of the cow herd, and the use of body condition as a management tool to develop and monitor nutritional programs. Using body condition scoring as a management tool can increase the profit potential of the cow/calf enterprise

Effect of Age of Dam on Heifer Progeny Performance

Cattle records were gathered and evaluated over a 12- yr period to investigate how cow age impacts heifer progeny growth and reproductive performance. Cow records from March and May calving herds, were categorized into young, moderate, and old groups based on their age at calving each year in the herd. Heifer calves born to young cows had lighter body weight at birth and adjusted 205- d BW than heifers from moderate and old cows. Heifer pre-breeding BW and pregnancy determination BW were not influenced by dam age. However, age of dam does impact the percentage of heifers to reach puberty prior to the start of breeding with no differences in percentage of heifers who calved within the first 21 d of calving in the subsequent calving season and pregnancy rates. Average number of calf crops from heifer progeny was different among all age of dam groups with young dams having more calves. Results from this study suggest older cows have a positive influence on growth and pre-breeding puberty status in female progeny during heifer development. Heifer progeny from young dams, however, had increased calf crops and longevity within the cowherd