No description available.
Mavimbela, David Thele
15 December 2006
Please read the abstract in the section 00front of this document / Thesis (PhD Agric (Animal Science))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted
Aucamp, Barend Bernadus
Tydens embrio ontwikkeling groei weefsel deur selvermeedering, maar soos wat soogdiere volwassendheid nader vind groei net plaas deur sel vergroting. Volwassenheid word beskou as wanneer spiergroei ‘n maksimum bereik. Groei sluit die neerlegging van vet in, maar spiermassa is van primêre belang. Die groeikurwe (Fig 1) waarin massatoename teenoor ouderdom vergelyk word, volg ‘n sigmoidale kurwe (Owens et al, 1993). Onder ideale toestande is die groeitempo van lammers relatief konstant van kort na geboorte totdat die helfte van volwassemassa bereik word, waarna dit geleidelik afneem tot volwassenheid (Black, 1983). Die afname in groeitempo begin gewoonlik met die bereiking van puberteit (Owens et al, 1993).
Energy and protein requirements of ewes, and the use of non-protein nitrogen [sic] by ewes and early weaned lambsNaseem, Muhammad Zafarullah January 1970 (has links)
In order to investigate the nutritional requirements of ewes during late pregnancy and early lactation, two groups of ewes were given 90 gms. Digestible Crude Protein (D.C.P.) during pregnancy and 225 gms. D.C.P./head/day during early lactation. During the last six weeks of pregnancy ewes in Group II, provided with maintenance + 100%, requirement of Digestible Energy (D.E.) made significantly greater liveweight gains (P<0.01) than those in Group I and fed maintenance + 50%, D.E. During early lactation ewes in Group I, provided with maintenance + 150%, D.E. lost significantly less weight (P<0.05) than those in Group II which were given maintenance + 100%, D.E. There were no significant differences in milk yield and milk composition between the two groups, however pre-weaning lamb growth in Group I was significantly greater (P<0.05) than that in Group II. Average daily gain of weaned lambs (weaned at 8 to 10 weeks of age) given pelleted rations containing 20%, protein was significantly greater (P<0.05) than those given 16%, protein but there were no significant differences between lambs fed 20% or 13% and between 16%, or 13%, crude protein. A higher proportion of single lambs in the group given 13% protein may have accounted in part for the better gain of this group. Results of the digestion trial with these lambs indicated that there were no significant differences (P<0.05) in the dry matter digestibility and the protein digestion coefficient of the three types of pellets but the nitrogen retention was greatest in the lambs fed the 20%, protein. The results of the second experiment conducted, to study the effect of non-protein nitrogen in the form of urea on milk yield and milk composition of ewes indicated that there were no significant differences in milk yield, milk composition and milk urea N level of the three groups of ewes fed equal amounts of supplemental nitrogen, during early lactation, as soybean, soybean + urea and urea alone. Ewes fed soybean or soybean + urea had significantly lower plasma urea nitrogen levels (P<0.05) than those supplemented with urea alone. There was no significant difference between the plasma urea nitrogen level of the former two groups of ewes. There were no significant differences in the pre-weaning growth of lambs nursing ewes fed on pellets containing soybean + urea and urea alone but the lambs from ewes fed soybean made significantly slower (P<0.05) gain than those from the other two groups. .The reason for this slower rate of gain is difficult to explain. Results of the trial conducted to investigate the use of urea nitrogen in early weaned lambs indicated that the lambs fed on pellets containing soybean made significantly greater gains (P<0.05) than those on pellets containing urea as the sole source of supplemental nitrogen. There were however, no significant differences in weight gain of lambs fed on pellets containing soybean or soybean + urea and between soybean + urea or urea alone. There were no significant differences between plasma urea nitrogen level of lambs fed on soybean or soybean + urea containing pellets and these lambs had significantly higher (P<0.05) levels of plasma urea nitrogen than those fed on pellets containing urea alone. The variation in the blood urea level of the lambs was thought to be due to variation in protein intake. Results of the digestion trial with lambs showed that there were no significant differences in the protein digestion coefficients and dry matter digestibilities of these types of rations. Pellets providing nitrogen from soybean resulted in greatest nitrogen retention. Results show that urea did not influence the milk yield or milk composition of the ewes but it was a poor source of nitrogen for early weaned lambs. / Land and Food Systems, Faculty of / Graduate
Bryant, Ronald George
Four main experiments were carried out to study the nutrient requirements and management of sheep raised in confinement. Experiment I was designed to study the reproductive performance and protein utilization of ewe lambs bred to lamb at approximately 14 to 16 months of age. Rapeseed meal was compared to soybean meal as a source of supplemental protein during the second half of gestation. Ewe weight gains and lamb birth weights were not affected by either the level or the source of protein. Neither dry matter nor protein digestibility were influenced by the stage of gestation of the ewe. No consistent results were obtained with regard to nitrogen retention of the ewes during the last half of gestation. The results suggest that 11% crude protein (CP) in the dry matter supplying approximately 68 g digestible crude protein (DCP) may be adequate for this class of ewes. The results also indicated that a level of 22% rapeseed meal may be included in the diet of gestating ewes without producing goitrogenic or other adverse effects. Experiment II was conducted to assess the performance of ewe lambs during lactation when fed rapeseed meal or soybean meal together with low quality roughage. Weight changes of the ewes and the average daily gain of the lambs over the eight week lactation period were not affected by the level or the source of protein. The results suggest that 10% CP in the dry matter supplying approximately 92 g DCP may be adequate for the class of ewe studied. A level of 25% rapeseed meal may be included in the diet of lactating ewes. In Experiment III wheat and barley were compared as energy sources in all-concentrate rations for lambs weaned at eight weeks of age. The cereal grains were fed in the whole, rolled, and pelleted forms together with a pelleted protein supplement. Digestiblity trials were also conducted to measure the digestibility of energy and protein as influenced by grain, process and level of intake. There was no difference in growth rate of lambs fed wheat or barley. Whole grains resulted in a faster rate of gain than the pelleted form. Digestibility of energy was not influenced by the method of processing. Protein digestibility was similar for the whole and rolled grains with a tendency for pelleting to depress digestibility of this nutrient. Increasing feed intake from maintenance to appetite resulted in a slight depression in nutrient digestibility. The results of this study suggest that processing of cereal grains for lambs is unnecessary from the standpoint of digestibility and would appear to be detrimental in terms of growth rate and feed conversion efficiency. Experiment IV was designed to study the influence of level of protein supplementation of whole barley based rations for early weaned lambs. A series of digestibility studies were conducted to measure the digestibility of dry matter and protein during three periods of growth. Results of this study demonstrated that 16% CP in the ration of lambs from 20 - 29 kg liveweight was sufficient to produce the most economical gain during this period of growth. In the period from 29 - 36 kg the lambs receiving 14% CP in the ration gained faster and had the best feed conversion efficiency. During the final finishing period the results suggest that one could continue to feed a 14% CP ration. The digestibility of dry matter and crude protein were not influenced by stage of growth of the animal. / Land and Food Systems, Faculty of / Graduate
Ross, James Pelter
The feeding of three different rations varying mainly in crude fat and crude fiber level at a high level of intake to pregnant and non-pregnant ewes had a number of effects on blood glucose, lactic acid, acetone plus acetoacetate, and total volatile fatty acid concentrations during the last three months of gestation for the pregnant animals (February, March, and April). There was no significant effect due to time on blood glucose level or on the level of blood ketone bodies, during the latter stages of pregnancy, for animals consuming high, medium or low roughage rations. The intramuscular injection of 1 mg./kg. body weight of growth hormone into pregnant sheep for 7 days during the last month of pregnancy, caused no significant effects on blood glucose, lactic acid, acetone plus acetoacetate, or total volatile fatty acids concentrations. / Land and Food Systems, Faculty of / Graduate
Studies on the influence of different planes of nutrition on Haemonchus contortus infection in lambs.Hamza, František. January 1968 (has links)
No description available.
Cooper, Donald Arthur
In view of the importance of alanine as a gluconeogenic precursor in ruminants, the objective of the present study was to assess the effectiveness of three techniques in estimating the metabolic parameters surrounding alanine in wethers fed a maintenance diet of alfalfa hay. A preliminary experiment utilized a blood flow technique to study the net production and/or utilization of both alanine and glucose by the portal drained viscera. Such a method involved evaluating the arterio-venous concentration differences of alanine and glucose, in conjunction with determining the rate of portal vein blood flow. Radioactively labelled ¹⁴C - alanine was administered as a single injection in the second series of experiments to estimate the metabolic parameters of alanine as well as its contribution to glucose synthesis. The L-U-¹⁴C-alanine was given intravenously through previously implanted jugular catheters and the fall in the specific activity of plasma alanine with time was determined. The line of best fit for the decay curve of the specific activity of plasma alanine was constructed by means of a computer using a multi-term exponential function which enables the estimation of such parameters as the pool size, space, total entry rate, irreversible loss and recycling of alanine. The per cent conversion of alanine to glucose was determined by the corresponding peak of glucose specific activity following the single injection of ¹⁴C - alanine. The turnover of alanine was also studied using a continuous infusion of L-U-¹⁴C-alanine without a priming injection. The specific activity of plasma alanine reached a plateau five hours after the beginning of the infusion. It was from these plateau levels that the rate of irreversible loss of alanine as well as its percent conversion to glucose was estimated. The results indicated that the single injection technique was able to partition the total entry rate of alanine into irreversible loss and recycling and thus prove more informative than a continuous infusion method. The present study also suggested that under certain physiological stress conditions in ruminants, where recycling becomes prominent, a continuous infusion approach may overestimate the actual rate of irreversible loss of alanine. / Land and Food Systems, Faculty of / Graduate
Mudaliar, Arcot Shrinivas Ramkishen.
Call number: LD2668 .T4 1965 M943 / Master of Science
Conway, Kenneth Loyd
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