The feasibility and economic value of DNA paternity identification were investigated and illustrated using Nevada beef cattle operations. A panel of 15 microsatellites was genotyped in 2,196 animals from 8 ranches with a total of 31,571 genotypes. Probabilities of exclusion for each marker within ranch and across ranches were computed. Joint probabilities of exclusion for the 15 microsatellites were also determined, resulting in values over 0.99 for any individual ranch and across ranches. Dropping 1 or 2 microsatellites with the lowest probabilities of exclusion resulted in joint probabilities greater than 0.99 and with marginal reduction compared with the probabilities with 15 microsatellites. Formulas for benefit-cost analysis for a DNA paternity identification program in beef cattle were derived. Genotyping 15 microsatellites with 20 calves per sire resulted in benefits of $1.71 and $2.44 per dollar invested at bull culling rates of 0.20 and 0.30, respectively. The breakpoints for the program to be profitable occurred when the ratio of the price of 1 kg of calf liveweight over the cost of genotyping 1 microsatellite was greater than 1.1 for a bull culling rate of 0.30. Benefit-cost analysis was also derived under incomplete DNA paternity identification using a lower number of DNA markers than necessary to achieve joint probabilities of exclusion of 0.99. Approximately a 20% increase in the benefit-cost ratio was achieved using 10 vs. 12 microsatellites with incomplete paternity identification. The greater the number of bulls in the operation, the lower the benefit-cost ratio of the paternity testing program. Low probabilities of exclusion and a high number of bulls in the beef operation reduced the benefit-cost ratio dramatically. The DNA paternity identification programs are feasible and may be profitable for free-range beef cattle operations.
The objective of this study was to assess prevalence of verotoxin-producing Escherichia coli (VTEC) in culled beef cows at the time of shipping to slaughter. Feces were collected from 82 cows on eight Nevada ranches during fall and winter (from September to January) after grazing rangeland forages. A random sample (n = 154) of potential VTEC isolates were tested for verotoxicity and were screened for the presence (polymerase chain reaction) and expression (VTEC-reversed passive latex agglutination assay) of the toxin genes (i.e., VT1 and VT2). Seventeen isolates from four ranches were VTEC. Of these, four had the VT1 gene, five had the VT2 gene, seven had both genes, and one did not have either gene despite its toxicity to Vero cells. Except for one isolate (i.e., untypeable that reacted with VT1-latex beads without having VT1 gene), the genotype and phenotype data of the VTEC isolates matched. Another isolate (O8:H- [nonmotile]) was verotoxic, but neither had nor expressed the toxin genes. Of the 17 isolates, four (from one cow) were O157:H7, 11 (from five cows on three ranches) were non-O157:H7 (two O8:H-, three O105:H-, three O116:H-, and three O141:H-), and two were untypeable. Because some of these VTEC serotypes (i.e., O8:H-, O141:H-, and O157:H7) are known to cause human illnesses, it is beneficial to identify VTEC-positive cows before slaughter. This is a critical step in any pre- or post-harvest strategy to minimize the risk of beef contamination with such pathogens.
Determining which management practices to focus on to improve profitability is a major challenge in any cow/calf operation. We used CowCost management simulation to evaluate the relative importance the major factors. The software generated 50 000 different management scenarios using values that were generated randomly, but within reasonable ranges of typical western cow/calf operations. Management factors studied by the model included the original cost of the cow, interest rate paid on money borrowed to buy the cow, salvage value of the cow at the end of her production life, percentage of calves the cow might wean, yearly cost per cow of the ranching operation, average weaning weight of the calf, and the average price brought by the calf. The model assumes calves will be sold at weaning and not held as yearlings. The model used these management factors to predict profit or loss, and to gauge the relative importance of the management practice. All scenarios were for one cow with an assumed production of 8 yr. Correlation analysis of the data showed that yearly cost was the most influential in determining profit or loss. The money received per pound of calf was next most influential. Weaning weight was the third most influential and weaning percent is fourth. The original cost of the cow, interest rates, and salvage value of the cow were far less influential on profit loss. While these final items, especially the cost of the cow and interest rate, receive a great deal of attention from most producers, they may not deserve that much attention, especially compared with other management inputs. The Problem Determining which management practices to focus on is always a problem in the cow/calf operations. To evaluate the relative importance of a number of factors, CowCost (management simulation software) was used to generate 50 000 different scenarios in ranch management. The model incorporated a variety of management factors into predicting profit or loss, used as the gauge to determine the relative importance of the management practice. These numbers were used to study relative importance of management factors. Background Most producers desire the management scheme that makes the most profit. A number of papers focus on details such as breeds and productivity of breeds. There are a number of broad management factors that should be considered first. Management can influence all of the factors and deciding which to concentrate on can be difficult. When there are many management options, computer modeling can successfully predict outcomes due to management changes. This paper explores the relative importance of these major factors through computer simulation of many different management situations. Study Description To evaluate the relative importance of a number of management factors, CowCost was used to generate 50 000 different scenarios in ranch management. CowCost is a program that evaluates management practices and the income potential from purchasing cattle. A number of management variables are included in the mod...
Management and marketing are key components of success and profitability of any beef cow/calf operation. There are many factors involved in management of a cow/calf operation and in marketing its products. These factors interact in a complex manner making any attempt to separate their effects, when predicting profitability as a function of management and marketing decisions, difficult and impractical. Therefore, we developed a simple computer program (CowCost, runs under Windows9S or Windows98) to enable producers to evaluate various management practices and their potential impacts on profitability. The program links the management and marketing variables commonly found in a cow/calf operation in an interactive way. This results in an immediate response to any changes in the input data and, therefore, provides the users with the ability to test many “what if ” scenarios and their subsequent effects on profitability. In turn, producers can check many different scenarios, prices, costs, and how they will affect the value of a cow. It is both a program to evaluate management ideas and profit potential of chosen scenarios. The program considers money borrowed to buy a cow, duration of the loan, cost of the cow, salvage value of the cow, yearly cow cost, calf weaning weight, calf price per pound and other variables to evaluate profit potential. Varying any one of these gives insight to management practices that could be emphasized to increase profit. The program allows investigation of the effects of costs relative to other inputs in decisions about purchasing cows. The Issue Marketing and management function together in beef cow/calf operations to make a successful business. Many functions go into marketing and management, and taken alone, each of these functions are simple. Combining these functions and determining their interactions is very complicated. Yet, evaluation of various management practices and their potential effects on profitability is very important to cow/calf operations. CowCost is a computer program that links many of the variables of management and marketing in an interactive way. This allows rapid changes in the input data to provide users with the ability to test many “what if scenarios ” and the subsequent effects on profitability. Background A major concern of beef cow/calf producers is trying to calculate the value of a cow, making a profit is the number one goal of most producers. Value depends on whether you are buying or selling. Sale price is a function of supply and demand and is largely established by the present market value of comparable classes and quality of cattle. Purchase price, when you are a buyer expecting to raise calves from the cow, should be evaluated in a different manner. The value of a potential brood cow is a function of a number of variables. Combining the effect of these variables is difficult and is in essence an input/output model. One of the problems with many input/output models is the failure to account for the salvage value of the cow and individual operator goa...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.