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Soybean meal-protected tallow has been commercially available in Canada for use in dairy rations, since 1975. The reported effects of feeding protected tallow to dairy cows have been variable and the prices of protected tallow supplements have been high. In view of the lower cost of canola meal relative to soybean meal in Canada, a study was undertaken to investigate the efficacy of feeding protected tallow made either from soybean meal or canola meal, to dairy cows in early lactation. Secondly, a comparison was made between the soybean meal-protected tallow and the canola meal-protected tallow. Twenty-seven cows from the University herd, comprised of 12 first-calf Holstein heifers, 3 Holsteins in their >2nd lactation, 4 Ayrshire heifers and 8 ≥2nd lactation Ayrshires, were used in a continuous feeding trial which was conducted from day of calving until the end of week 20 of lactation. Cows were randomly assigned within breed and lactation category (9 cows per treatment) to one of 3 isonitrogenous (16 % crude protein) concentrates: a) no protected tallow (control); b) 8 % soybean meal-protected tallow; or c) 8 % canola meal-protected tallow, which they received during weeks 1-15 (inclusive). From the beginning of week 16 until the end of week 20 all cows were fed a 16 % crude protein, post-treatment concentrate (no protected tallow). Throughout the 20-week trial the ratio of concentrates to cubes offered was maintained at 70:30 with feed intakes being ad libitum. Between weeks 13 and 16, 4 cows per treatment were assigned to a digestibility trial involving a 7-day total Collection of faeces and urine. Protected tallow rations produced significant increases over the control ration (P<.05) in the yields of milk, 4 % fat-corrected milk and milk fat, and protected tallow rations increased the efficiencies of conversion of gross energy, digestible energy, crude protein and digestible protein to milk, 4 % fat-corrected milk, solids-corrected milk and milk energy (P<.05). The apparent digestibility of ether extract and the concentration of plasma non-esterified fatty acids were significantly higher on rations with protected tallow (P<.05). Milk protein % was significantly reduced below the control level with rations containing protected tallow and rumen acetate and the acetate:propionate levels were also decreased. Protected tallow rations had no significant effect on the intakes of dry matter, gross energy, digestible energy, crude protein or digestible protein or on the apparent digestibilities of dry matter, organic matter, gross energy, nitrogen, acid-detergent fibre, ash, calcium, phosphorus or magnesium (P>.05). Also the yields of solids-corrected milk, milk gross energy and milk protein, the plasma glucose concentration and average daily gain were not significantly different, on rations containing protected tallow, compared with the control ration. There was no significant difference between the soybean meal-protected tallow ration and the canola meal-protected tallow ration for any parameter measured except apparent digestibility of ether extract which was significantly higher for the canola meal-protected tallow ration (P<.01). / Land and Food Systems, Faculty of / Graduate

Two novel strawberry cottage cheese desserts were developed in this study and evaluated regarding their microbiological, physico-chemical and sensory characteristics. The purpose of the study was to develop cottage cheese desserts, both full-fat (FFCCD) and skim milk (SMCCD) from fresh cottage cheese. Four formulations were made by adding fruit pulp to the cottage cheese. These were; treatment 1 = 0 % fruit pulp, treatment 2 = 10 % fruit pulp, treatment 3 = 20 % fruit pulp and treatment 4 = 30 % fruit pulp. All of the four treatments were found to be acceptable by a consumer panel and preference scale increased with an increase in the percentage fruit pulp added, texture and appearance. The microbiological status of the treatments was also at acceptable levels at the proposed shelf life of 21 days after which, spoilage microorganisms started to grow. The added fruit pulp increased their keeping quality by increasing the shelf life. The composition of the two desserts types was also acceptable and compared well with results from other studies. It still remains that the fat content played a major role in distinguishing the two dessert types. The effect of the fat, fruit and fat/fruit interaction was evaluated. During shelf life studies, the effect of the fat, fruit, fat/fruit, day, day/fat, day/fruit as well as the day/fat/fruit interaction was also evaluated on the microbiological, pH and titratable acidity values of the treatments with a tendency to decrease by day with an increase in the percentage fruit added. It could then be concluded that the addition of fruit pulp to the fresh cottage cheese increased its shelf life, acceptability and the new product serves as an alternative to fruit blended yogurts which exist in the market. The methods used could be adapted to a small scale and thus be part of food security programmes in South Africa. However, for the new product to partake in the dairy industry, it is recommended that the product be marketed properly. / Dissertation (MInstAgrar)--University of Pretoria, 2010. / Food Science / unrestricted

The study investigates the role of co-operatives in smallholder dairy production and marketing in Swaziland. The study was undertaken to determine the effectiveness of cooperatives in improving production and marketing as well as in minimisation of transaction costs. Expectations were that co-operative members perform better than independent farmers in terms of production and productivity, have larger herd sizes, generate a higher income, and also incur lower transaction costs indicated by a higher quantity of milk sold. Results of the survey indicate that co-operatives play a positive role in production and marketing activities of smallholder dairy farmers, although certain developments such as provision of support programmes need to take place in order for them to make a more significant contribution. Co-operative members produce and sell higher quantities of milk (19.3% higher and 24.5% higher respectively), which is mainly attributed to provision of technical inputs. Co-operatives also provide farmers with a reliable market, although price paid is lower (35% lower) compared to that of independent farmers in the same areas. Low income is compensated by the fact that co-operative members incur lower transaction costs indicated by the lower transportation costs per unit of output, adequate access to market information through frequent visits of extension officers and regular training, as well as a lower percentage of losses incurred compared to independent farmers. Results of the study confirm the hypothesis that co-operative members perform better and incur lower transaction costs than independent farmers. Results of the regression model indicate that distance, access to market information, milk output and co-operative participation significantly influence the quantity of marketable milk, and hence contribute to lower transaction costs incurred. The results show that co-operative farmers incur lower transaction costs although they sell their milk at a lower price. Nevertheless, the fixed price effect renders co-operative farmers not susceptible to price fluctuation risks that independent farmers are faced with because of their volatile prices. The study suggests that there is a need for support programmes that will help motivate individual farmers and strengthen co-operatives, as their contribution to smallholder production and marketing is still marginal. Support programmes include provision of a supportive policy environment, infrastructure development, access to financial and credit facilities and improvement of training and extension to provide more extensive dynamic opportunities to farmers. In terms of further research, the study recommends that a similar study be undertaken in other areas of Swaziland so that the study is representative of the whole country. In addition, further research is needed on performance of dairy cooperatives to enable replication of successful co-operatives in the country which will go a long way in improvement of the dairy industry as a whole. / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Agricultural Economics, Extension and Rural Development / unrestricted

Implications of water chemistry on milk synthesis are not well described yet water is an important nutrient for dairy cattle. High mineral concentrations (>0.3 mg/kg Fe and others) may be associated with natural levels in ground water, contaminating sources, drought conditions, or storage systems. This study evaluated effects of added iron in bovine drinking water on milk composition (Ca, Cu, Fe, P) measured by inductively coupled plasma mass spectrometry and oxidative stability measured by thiobarbituric acid reactive substances assay for malondialdehyde (MDA), volatile chemistry and sensory analysis (triangle test). Prepared ferrous lactate treatments, corresponding to 0, 2, 5, and 12.5 mg/kg drinking water levels were given abomasally (10 L/d) to 4 lactating dairy cows over 4 periods (1 wk infusion/period) in a Latin square design. Milk was collected (d6 of infusion), processed (homogenized, pasteurized), and analyzed within 72 h of processing and 7 d of refrigerated storage. No differences in MDA (1.46�0.04 mg/kg) or iron (0.22�0.01 mg/kg) were observed in processed milk. Cross effects analysis (treatment*cow) showed significant differences in calcium, copper and iron (P < 0.05). Sensory differences (P < 0.05), in treatment vs. control, suggested iron from water sources contributes to milk flavor changes. A case study with high and low (0.99; 0.014 mg/kg) iron treatments revealed no significant differences (P > 0.05) in mineral composition (0.23�0.06 mg/kg Fe) or MDA (0.77�0.03 mg/kg) of raw milk. Iron added to milk causes changes in oxidation; high levels of iron in bovine drinking water may not have observed effects. / Master of Science in Life Sciences

Progesterone is essential for the maintenance of pregnancy in cattle. Recent trends in decreased reproductive efficiency in dairy cattle have led researchers to believe that increased catabolism and decreased peripheral concentrations of progesterone are at fault. The objective of this study was to determine if the induction of an accessory corpus luteum (CL), via human chorionic gonadotropin (hCG), alters blood perfusion of CL, peripheral concentrations of progesterone, or hepatic steroid inactivating enzymes. We hypothesized that the induction of an accessory CL would decrease blood perfusion of the CL, decrease peripheral concentrations of progesterone, and increase clearance of progesterone in the liver. Total blood perfusion of the CL was increased in cows with 2 CL compared to cows with 1 CL, but concentrations of progesterone and hepatic enzymes did not differ. Overall, the increased blood perfusion in cows with 2 CL did not alter concentrations of progesterone or progesterone clearance.

Aflatoxins are naturally occurring carcinogens found on grains, particularly in warmer climates. Because of their carcinogenic properties, they are strictly regulated and are only allowed in minimal amounts. Aflatoxin B1, the most potent naturally occurring carcinogen known, is metabolized in the liver to form aflatoxin M1, which is present in the milk of lactating animals. If aflatoxin concentrations are elevated above legal limits, the milk cannot be used for human consumption. Because of this, research has been conducted to evaluate ways to mitigate its absorption in the animal and prevent transfer to the milk. One such way is through the use of clay adsorbents. The current studies aimed to evaluate the efficacy of two different clay adsorbents at preventing aflatoxin transfer to the milk of Holsteins fed a known concentration of aflatoxin.

Regular consumption of dairy is thought to aid in preserving lean body mass while decreasing body fat, however, studies have reported inconsistent results. The overall aim of this cross-sectional study was to examine the influence of dairy consumption on body composition, specifically body fat percentage, among college-aged individuals in Mississippi. Total dairy consumption, type of dairy, and the relationship between race and sex were examined in 580 participants aged 18-26 years. Two-tailed correlation tests revealed a nonsignificant relationship between frequency of dairy consumption and body fat percentage among males, (r = .02, p = .68, n = 98) and females, (r = .06, p = .17, n = 469). There was also a nonsignificant interaction among race categories and dairy consumption. Future studies examining college-aged individuals should be performed with a more diverse sample to see if a relationship exists.

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