Master of Science / Department of Agricultural Economics / Ted Schroeder / Feeder cattle are placed into feedlots at varying weights. This placement weight is the result of procurement decisions by cattle feeders and of marketing decisions by cow/calf and stocker/backgrounder producers. Increased understanding of the behavior of these markets can help both buyers and sellers of feeder cattle make these decisions. Past research has used linear or quadratic variables or interaction variables in order to model the effects of weight on price. This study instead divides the market for feeder cattle into ten distinct subsets which are evaluated independently. The feeder cattle market for four major cattle feeding states in the Southern Great Plains (Nebraska, Kansas, Oklahoma and Texas) was divided into ten subsets, five in each gender. Each of these represent feeder cattle coming to market in a 50 pound weight range, centered upon 525, 625, 725, 825 and 925 pounds. Each of these subsets was analyzed using seven independent variables selected based upon previous research and economic rationale. These variables were the live futures price, previous feedlot returns, feeder cattle inventory, interest rate, feedlot capacity utilization, cost of gain and pasture conditions. The data for these variables were collected from public sources, aggregated into monthly observations and differenced to correct for nonstationarity. Analysis was conducted using ordinary least squares regressions. Results are reported and trends between weight classes discussed along with their implications. Findings support that feeder cattle of different weights are not perfect substitutes and that market and production factors do not influence all weights of feeder cattle the same. In fact, factors which positively and negatively affect feeder cattle price seem to signal that demand for, or in the case of pasture supply of, feeder cattle of a particular weight has changed and that placement price-weight relationships will adjust accordingly.

Lactation and weaning weight relationships were studied in 37 cows grazing Southern Utah irrigated pastures during the summer of 1979. The herd included 23 Hereford cows ranging in age from 2 to 12 years and 14 Simmental-Hereford half-blood cows aged 3 to 9 years. The suckling calves were sired by Hereford bulls. The average daily milk yield of 6.16 kg was affected by the cow breed. Simmental-Hereford cows produced 7.11 kg of milk per day, while the Herefords produced 5.21 kg per day. Milk production declined with increased days in lactation. The decline was linear in the Simmental- Hereford cows and quadratic in the Herefords. Milk production was also affected by the sex of the suckling calf. Heifer calves received 6.44 kg per day compared t o 5.80 kg per day for bull calves. Calf birth weight and test day weight influenced milk yield as cows nursing heavier calves produced more milk. Cow breed affected milk composition. Simmental-Hereford cows had higher percent solids-not-fat, while Herefords were higher for percent protein. Calf weights were affected by sex of calf. Bull calves weighed 33 .89 kg at birth, while heifers weighed 32.14 kg. At weaning, bulls weighed 188.63 kg, while heifers weighed 177.14 kg. While no breed difference was evident for birth weight, calves from Simmental-Hereford dams weighed more over the duration of the study than calves from Hereford dams. The difference between the mean 205-day adjusted weights for the calves from the Simmental-Hereford and Hereford cows was 24.96 kg (230.50 kg and 205.54 kg, respectively). Milk yield was highly correlated to calf gain (r 0. 71). The breed of dam influence upon weaning weight was largely a result of differences .in quantity of milk produced.