Two distinct experiments were conducted. Experiment 1 was conducted to investigate the effects of nutritional conditioning and flushing as a means of improving reproductive performance of female mink. In Exp. 2, vegetable oil and corn syrup were fed during lactation to ascertain whether this nutritional regimen would improve growth of kits and to maintain the female's condition. Ninety-nine Standard Dark kit females in Exp. 1 were assigned to a group (IBC) that was restricted-fed a low energy breeding diet (14.6 MJ/kg DM) beginning in September to keep the animals in lean condition throughout the winter. Concomitantly, a control group (IA, N=51) was full-fed a higher energy diet (16.3 MJ/kg DM) until subjected to short-term conditioning with the breeding diet in January and February. All mink were individually conditioned to average under 900 g weight, which is considered an opti a weight before the meating season. At the beginning of the breeding season one-half of the mink in the experimental group (IBC) were exposed to nutritional flushing (hereafter designated IC) while the other one-half of the mink (IB) were moderately-fed for the entire mating period, as was the control group (IA). Flushing consisted of slight restriction of feed for 2 weeks followed by full feeding from March 1, 3 days before the mating season, until second mating. On April 15, all groups were further divided in half: one-half was fed moderately, while the other one-half was fed to appetite. This experiment failed to improve litter size significantly. Average litter sizes at birth for groups IA, IB and IC were 6.16, 5.74 and 6.48, respectively. However, the relationship between litter size and weight change (%) during flushing was significantly positive and followed a quadratic curve (p = 0.010, R² = 13.8 %). As a consequence, weight increase during flushing (9.32%) was too low and suggests a need for higher energy density during flushing. Conception rate of mink in this experiment was very high (96.7%), apparently as a result of individual conditioning of the mink. Percentage of stillborn kits was higher than normal (highest in the flushing group) but the difference was not significant statistically. Litter sizes at birth based on full (F) and restricted feeding (R) were 5.88 and 6.40, respectively (p=0.07). In relevant field observations on two commercial farms, it was noticed that obesity of females prior to mating lowered reproductive performance. Blue Iris females weighing over 1400-1500 g at mating often did not conceive and had few if any kits at weaning. In Exp. 2, lactating Blue Iris females with kits were fed either lard or vegetable oil as a fat source (40 % of total fat) and cereal (wheat:barley) or corn syrup supplement as a carbohydrate source (40%). Positive effects of vegetable oil on kit weights and of corn syrup on weight loss of dams were revealed. Weight of kits fed lard and vegetable oil were 315 and 332 g (p=0.06) at 6 and 572 and 598 g (0.03) at 8 weeks of age, respectively. Weight losses of dams from parturition to 6 weeks of age averaged 283 and 154 g (p=0.06) for cereal treatment and the corn syrup supplemented treatment, respectively. / Graduation date: 1992

Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 95-99).

Thesis--Wisconsin. / Includes bibliographical references (leaves 72-75).

The primary objective of this study was to compare horse meat, whale meat, chicken wastes and herring as supplementary animal protein sources in rations for mink during maintenance, reproduction and growth. Part of the rations were canned and part of the rations contained a commercial antioxidant. The results of the maintenance experiment indicated that there were no statistical differences between the rations. In the reproductive phase of the experiment, the mink receiving the canned rations had almost complete reproductive failure whereas the mink receiving the frozen rations had a kit crop that was below average. There were significant differences between the rations in the growth phase of the experiment. The rations containing Horse Meat, Whale Meat and Chicken Waste A were superior to those containing Chicken Waste B and Herring. The difference between the two chicken wastes has been attributed to the variability of the composition of chicken waste. The below average performance of the mink receiving the Herring ration was not due to protein of inferior quality, as evidenced by its high Net Protein Utilization value, but probably due to the results of oxidative rancidity. The addition of the commercial antioxidant to the rations had no significant effect on the performance of the mink during maintenance and reproduction but did retard the growth of the kits. The antioxidant failed to prevent the destruction of thiamine in the frozen and canned rations but did afford some protection for Vitamin A in the canned rations. The Net Protein Utilization values for the fat extracted supplementary protein sources differed considerably. Herring was the highest and was followed by Horse Meat and Whale Meat, Chicken Waste A and Chicken Waste B. The digestibility trials indicate little differences between the rations except for fat digestibility. The high fat digestibility suggests that mink can utilize high levels of fat from varying sources. The low "carbohydrate" digestibility indicates that mink may have difficulty in utilizing the cereal portion of their rations. The variability in feed consumption of the mink receiving the canned rations was attributed to the differences in the digestible energy contents of the rations. Regression equations relating feed consumption to body weight were calculated for the various ration groups. / Land and Food Systems, Faculty of / Graduate

The spontaneous occurrence of a liver disease in mink (Mustela vison) prompted an investigation of the animal's environment in the search for a possible aetiological factor. The pathological findings suggested that the disease was diet-induced and possibly resulted from the presence of a toxic factor in the feed. A series of experiments were carried out to ascertain if the condition arose through the action of a transmissible infective agent or from an inadequate supply of some essential nutrient. No evidence was obtained in support of either of these possibilities. Since the pathology noted was suggestive of a hepatotoxic factor or factors and was unlike any of the described intoxications arising from bacterial metabolites, major attention was given to a study of the possible role of the fungi as causative agents. Some fungi, when given the necessary conditions of temperature, moisture and substrate, elaborate toxins that are poisonous to a large number of species. The possibility that a fungal toxin was the cause of the disease in mink was therefore investigated. A literature review covering the mycotoxicoses has been compiled. In order to test the susceptibility of the mink to fungal toxicosis, a model was set up in which mink were fed a ration containing a known fungal toxin, aflatoxin. The mink proved highly susceptible to this toxin. The pathology of aflatoxicosis in the mink has been documented. The fungal population of the mink ration and its cereal ingredients was examined for toxin-producing fungi. A series of toxicity assays were conducted to screen the large number of organisms isolated from mink rations. Toxigenic fungi were isolated from: wheat used in mink ration formulations. The role of cottonseed oil as an agent contributing to this liver condition has been investigated. It is suggested that cottonseed oil either contains a toxic component or contains a specific factor which can be used by a fungus in some phase of its metabolism, and that the by-product of this metabolic pathway may accumulate as a toxic compound. / Land and Food Systems, Faculty of / Graduate

Graduation date: 1991

Thesis (Ph. D.)--University of Wisconsin--Madison, 1942. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1953. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 36-38).

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis--University of Michigan. / Reprinted from the Journal of comparative neurology, vol. 83, no. 2, October, 1945.