Four groups of weanling Hereford heifers were placed on four different winter planes of nutrition for a period of two years according to the following pattern: Group I - Low plane of nutrition Group II - Medium-low plane of nutrition Group III - Medium-high plane of nutrition Group IV - High plane of nutrition During the summer seasons the heifers were kept on pasture providing the same feeding level for all animals. The one year old heifers were bred during the months of June and July. All animals were weighed weekly and feed consumption was recorded weekly. To illustrate the growth rate of the heifers, K-values were calculated for all animals by the method of least squares and their growth curves were constructed. At the end of the second winter period all parturition data were carefully recorded and the rate of growth of the calves studied. From the results obtained in this experiment the following conclusions can be drawn: (1) The first post-weaning winter period is very important in regard to the feeding level of young growing heifers. The medium-low plane of nutrition (Group II) showed the best results from the economic point of view. (2) Young heifers can be bred as yearlings if the previous winter-feeding level allows them to grow continuously and to reach at least 700 pounds body weight before the breeding period starts. (3) The gestation period did not result in a decreased growth rate of the bred heifers. (4) The physical difficulties of parturition in two year old heifers do not appear to be insurmountable if the winter plane of nutrition is adequate. (5) The lactation period means a heavy drain on the young female hence a high level of nutrition must be provided in terms of sufficient amount of pasture dry matter during the grazing season. (6) Average birth weight of calves was 62.9 pounds, being higher for bull calves than heifer calves. (7) Pasture dry matter requirements for beef cattle may be calculated from the following equation: DM = 0.17 w•⁷ (w is animal weight given in pounds) / Land and Food Systems, Faculty of / Graduate

Five experiments in series, requiring a total of 3,000 chicks, were conducted to test modifications of and supplements to the Connecticut broiler ration. Wheat and/or No. 1 recleaned ground feed screenings were tested to replace the corn of the original ration. Soybean oil meal and / or fishmeal alone or in combination with meatmeal were tested as sources of supplementary protein. Furthermore, two crude fermentation antibiotic preparations, arsonic acid and B-complex vitamins were tested as supplements to the Connecticut broiler ration. Good quality feed wheat can replace the corn content of the Connecticut broiler ration on a pound per pound basis. The excess protein in a modified Connecticut broiler ration in which the corn was replaced with wheat cannot be reduced by lowering the level of supplementary protein without slowing the growth rate of chicks. No. 1 recleaned ground feed screenings when incorporated into the Connecticut broiler ration as the sole grain did not promote as great a growth response in chicks as a combination of wheat and corn. The efficiency of feed utilization was lower with the feed screenings ration than with the ration with corn and wheat. However, when No. 1 recleaned ground feed screenings replaced one-half of a grain mixture in a chick starting ration the chicks grew at the same rate as the chicks receiving the ration in which no replacement was made. The mixture of meatmeal, fishmeal and soybean oil meal of the Connecticut broiler ration was superior in promoting faster chick growth than was a ration containing either fishmeal or soybean oil meal as sole sources of supplementary protein. A combination of fishmeal and soybean oil meal as a source of supplementary protein was superior to either protein supplement alone in promoting the early growth of chicks. The fishmeal, when included as the sole source of supplementary protein, promoted the most efficient utilization of feed, though such a ration did not produce maximum growth. All the modified Connecticut broiler rations, when supplemented with crude commercial antibiotic preparation gave an increased growth rate in chicks. The extent to which the antibiotic supplement increased the growth rate depended on the basal ration used. In all instances antibiotic supplemented rations were more efficiently utilized than were the unsupplemented control rations. The addition of arsonic acid promoted a greater growth response in chicks fed this supplemented ration than the unsupplemented control rations. This increased growth rate of chicks receiving the arsonic acid persisted to seven and one-half weeks. The addition of B-complex vitamins to the Connecticut broiler ration promoted a growth response in chicks equal to the growth response of chicks receiving an antibiotic supplemented Connecticut ration. The extent to which the mixture of vitamins increased the growth rate depended on the basal ration used. / Land and Food Systems, Faculty of / Graduate

A study has been made on the growth stimulatory-effect of antibiotics when fed to chicks as supplements to different rations. A total of 9 biological tests employing 1280 chicks were carried out. Chicks fed the Connecticut ration and modifications thereof showed a significant growth response to aureomycin supplementation of the rations. The efficiency of feed utilization was improved by the addition of aureomycin to the rations in this experiment. The effect of aureomyoin has been tested in rations in which the protein level has been adjusted to 16%, 17.9%, 19.5% and 22% respectively. The basal rations used consisted of ground corn and wheat as the cereal grain and soybean oil meal and fishmeal as the protein supplements along with additional vitamins and minerals to balance the ration. The results showed that aureomycin did not lower the dietary requirement of the chick for protein. A test was made on the effect of antibiotics on growth of chicks when fed in rations which were deficient in specific amino acids. A wheat ration deficient in lysine and a corn ration deficient in tryptophan have been used. The results showed that antibiotics did not lower the dietary requirement of the chick for either lysine or tryptophan. Antibiotics were fed in chick rations containing different amounts of available carbohydrates. It was found that antibiotics did not lower the dietary requirement of the chick for carbohydrate. A comparison of aureomycin and penicillin showed no difference in growth stimulating properties between the two antibiotics under the conditions of the different experiments. Aureomyoin supplement (aurofac) promoted the same growth response at 0.05 and 1.0% levels. The greatest growth response to antibiotics was obtained when the chicks were fed a diet adequate in available carbohydrates and protein and balanced in amino acids. / Land and Food Systems, Faculty of / Graduate

This thesis is the study of the literature pertinent to the assessment of growth in addition to the analysis of growth data obtained from the Albino Rat, Yorkshire Swine, Black-Tail Deer and a group, of ten Hereford Bulls. It has been concluded that animals grow at a constant percentage rate relative to body weight over each distinct portion of their growth curve. A significant error in the expression of rate of gain is introduced if animals growth rate is calculated over any but an instantaneous period. The latter is possible because growth of an animal body is directly proportional to the protoplasmic mass, a first order reaction and as such is exponential and when the expression is integrated, the slope of the' regression line, logarithm of body weight on time is provided over the period when relative growth rate is constant. From the results of ration variations with male Wistar rats it was concluded that upon returning to ad libitum feeding they will grow at the same relative rate as their controls despite thirty per cent reduction below ad libitum intake over periods up to two thirds of the birth to sexual maturity phase. The extrapolation is made that beef bull calves proceeding from varying environments normally, experienced on pure-breeding establishments will not provide biased data when placed on a test ration and allowed a period for the rumen microflora to become adjusted to the new ration. / Land and Food Systems, Faculty of / Graduate

In Study I alfalfa-bermuda grass hay or oat straw was fed with rolled barley, pelleted beet pulp, soybean oil meal and cracked wheat, in various proportions, in twenty protein-supplemented rations to immature Hereford steers. A control ration of 10% long straw, 78% rolled barley and 12% soybean oil meal was included. The best results were obtained with a roughage level of 10%. However, it was shown that it was feasible to feed roughage levels as high as 40% without detrimental effects to either average daily gain, feed efficiency, or carcass quality. In Study II various feed grains were fed in the ratio 90:10 (concentrate to roughage). The Canadian feed grains of barley and wheat were compared with corn. Various ratios of these feed grains were also compared. Excellent gains and feed efficiencies were obtained on all rations and it was shown that the cost of the grains available would be the largest factor in determining which to use. / Land and Food Systems, Faculty of / Graduate

The physiological effects of excess vitamin A are frequently studied in the investigation of the systemic function of the vitamin. The liver vitamin A storage efficiency of dietary excesses of vitamin A and the effect of excesses of the vitamin on alimentary cholesterolemia, the one-stage prothrombin time and the one-stage euglobulin lysis time were investigated in several genetically distinct populations of chickens. Birds of a New Hampshire (NH) line were found to store vitamin A in the liver from the diet more efficiently than birds of three White Leghorn (WL) strains (D,K and B) and of one broiler strain. An excess of dietary vitamin A reduced alimentary cholesterolemia in the NH chicks but increased alimentary cholesterolemia in the D chicks. There was no effect of hypervitaminosis A on the blood cholesterol concentration of either the D or the NH chicks receiving a low-cholesterol diet. No carryover effect of vitamin A upon removal of the excessive quantity of the vitamin from the diet, could be demonstrated on alimentary cholesterolemia in either the D or the NH chicks. The efficiency of the intestinal absorption ofcholesterol was increased in both the NH and the D chicks by an excess of vitamin A. The liver-to-blood partition ratio of cholesterol was increased by excess vitamin A administration in the NH chicks, but was decreased by excess vitamin A in the D chicks. The one-stage prothrombin time of D,K,B, and NH chicks was unaffected by the dietary administration of large excesses of the vitamin from day-old to three weeks of age. Chicks of a Black Australorp (A) line, however, responded to large excesses of the vitamin in the diet with an increase in one-stage prothrombin time. A single intramuscular injection of menadione (5 mg/kg body weight) brought the prolonged prothrombin times of the A chicks to normal within twenty hours. The one-stage euglobulin lysis time of NH,D and A chicks was decreased by the inclusion of large excesses of vitamin A in the diet of the birds from day-old to six weeks of age. Intramuscular administration of menadione (5 mg/kg body weight) was without effect on the shortened lysis times within twenty-four hours. Removal of the excessive quantities of vitamin A from the diet for six weeks failed to affect the shortened clot lysis times of the A hypervitaminotic chicks. Vitamin K deficiency induced in a Shaver strain of WL chicks by feeding the birds a K-deficient diet, had no effect on the euglobulin lysis time. The results of the present experiments extend knowledge of the effects of hypervitaminosis A on the induction of alimentary cholesterolemia and on the blood coagulation mechanism in the chicken. / Land and Food Systems, Faculty of / Graduate

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

The effect of heat treatment on the protein quality and the metabolizable energy value of rapeseed meal was investigated. Different rapeseed meal samples were autoclaved at 121° c for different times. a significant reduction (p < 0.05) in the in vitro protein digestibility resulted from the autoclaving treatment. Further reduction in protein digestibility occurred when samples were autoclaved with glucose. Poor growth and feed efficiency in the chicks were observed due to feeding of autoclaved rapeseed meal ration. Lysine supplementation of autoclaved and unautoclaved rapeseed meal improved growth and feed efficiency. Maximum growth on the control ration was obtained with 0.16% lysine supplementation whereas 0.24% maximized the growth of chicks on autoclaved rapeseed meal. No significant effect was observed on liver weight expressed as percentage of body weight, however, pancreas weight was significantly greater (p < 0.05) in birds receiving autoclaved rapeseed meal than the controls. There was no significant difference in metabolizable energy value of autoclaved and unautoclaved rapeseed meals. / Land and Food Systems, Faculty of / Graduate

In Part A of Study I, six groups of female standard mink were fed (once daily) either 5, 10, or 15 mcgm. of DES/mink/day or a forage antiestrogen extract at levels of 5, 10, or 15 gm. equivalent of alfalfa/mink/day. In Part B, seven groups of female pastel mink were fed (once daily) 15 mcgm. of DES/mink/ day prior to and at various stages of the gestation period. Also, the antiestrogen extract was again fed (once daily) at levels of 5, 10, or 15 gm. equivalent of alfalfa to three groups of female pastel mink after implantation of the fertilized egg had occurred. From the results of Part A and B of Study I it is evident that DES at levels as low as 5 to 15 mcgm/ mink/day caused complete reproductive failure. At the 15 mcgm. level it is possible to prevent or disrupt pregnancy if the hormone is administered for at least one week during the period starting one week before breeding and ending 30 days prior to parturition. The forage antiestrogen at levels between 5 and 15 gm. equivalent of alfalfa reduced the number of kits per litter from 5.8 to 1.6. The feeding of various levels of DES or the antiestrogen extract did not adhere to a dose/response relationship either in interrupting pregnancy or reducing the number of kits per litter. The DES, fed at levels of 5, 10, or 15 mcgm./mink/ day was a more potent antifertillty agent than the forage antiestrogen fed at levels equivalent to 5, 10, or 15 gm. of alfalfa. In Part A of Study II, 200 mature male and female mink of a variety of colour phases were divided into five groups. The groups were fed (twice daily) rations varying in crude protein (36.6 to 44.8%, on a d.m. basis) and gross fat (21.3 to 28.9%, on a d.m. basis). In Part B, 280 pastel and standard kits (6-7 wks. old) were fed (twice daily) rations varying in crude protein (39.0 to 54.3%, on a d.m. basis) and gross energy (5.20 to 5.52 Kcal/gm. dry feed). From the results of Part A and B of Study II it is evident that rations containing 35 to 40% crude protein and 20 to 25% fat, on a dry matter basis, are satisfactory for the late growth and maintenance requirements of mink. The mean apparent digestibility coefficients obtained in these studies for dry matter, protein, fat, and energy are 66.38, 74.05, 87.20, and 73.74%, respectively. As the apparent digestible energy (A.D.E.) was raised from 353.4 Kcal/100 gm. dry matter to 426.0 Kcal/100 gm. and as the apparent digestible nitrogen (A.D.N.) level reached 4.980 gm/100 gm dry matter, the early growth of both male and female mink was improved. Maximum early growth rate was obtained in kits when the ration contained 85.54 Kcal of A.D.E./gm A.D.N. (13.6 Kcal gross energy/gm gross protein). Also, increasing A.D.E. content in the diets had a definite protein-sparing effect. Maximum nitrogen retention was obtained when the diet contained 426.0 Kcal of A.D..E./100 gm. of dry feed. Finally the results suggest that the growing male kits (from 6-28 weeks of age) were capable of utilizing feeds more efficiently than female kits of the same age. / Land and Food Systems, Faculty of / Graduate

In recent years research has expanded the knowledge one has of the actual costs Involved in the growth process of meat producing animals. These studies have shown that at the higher weights a larger proportion of the gains are made up of high cost fat tissues. Initially it was thought that this fat deposition served a useful purpose in making meat tender, but it is now known that this original premise was incorrect. Fat is no longer desired by the consumer above a certain minimum level. The feedlot operator therefore has the option of taking advantage of this phenomenon and shipping animals at a lighter weight, at a lower cost, and with the possibility of doing this at a higher profit margin than is the case at present. A study has been made of the total costs involved in the production of a pound of live animal weight under feed-lot conditions and of the changes in these costs that occur as the animal achieves a higher total body weight. It was found that on the average, each additional pound of gain requires between .006 and .028 more pounds of feed than did the previous pound. As a result of these studies, an Economic Shipping Weight was proposed as a means of signifying the beginning of an increase in the average cost of production and hence, a decrease in. the rate of return to investment. The Economic Shipping Weight was defined as that weight at which the feed cost of an additional pound of gain is equal to the current value of a pound of live animal weight. In the application of this theoretically derived shipping weight to a practical feedlot operation having a total fixed investment of $162,938.00, it was found that the total return to investment was increased from $8,822 to $22,503. This increase resulted in a change in the rate of return to investment from 5.44% to 13.81%. The major part of this increase in the total margin was due to a reduction in the average feed cost of each pound of gain from 20.2¢ to 17.4¢. The total margin between sales revenues and animal purchase and feed costs was increased by $5,485.00. This reduction in feed costs was caused by a lowering of the average amount of feed required per pound of gain as the animals were theoretically shipped 41 lb. lighter than in the actual operation. Originally they were sold at an average weight of 998 lb. Seventy-six percent of them received a Choice grade. The analysis was carried out under the assumption that they would only receive a Good grade price at the Economic Shipping Weight. Other savings arose from a reduction in the total interest charges on feed purchases because of the lower total feed consumption, and from a reduction in the total feed freight bill. These two savings amounted to $4,716.00. The remaining saving resulted from a smaller in process feed cost. A study was also made of the relative advantages for the beef industry of stressing the production of Good grade beef as opposed to Choice grade beef. It appears that an economic advantage could be gained by the packing house operators, feedlot operators, and retailers, if this were to become the main grade produced. As consumers are now making most of their meat purchases on the basis of a lack of fat, Good grade meat is also more acceptable to them. The feasibility of using Dairy breed animals as a meat source was examined as a means of producing leaner meat at a lower cost than beef breed meat. These animals were shown to have a definite economic advantage at any body weight because they used feed more efficiently. Dairy breed bulls were also shown to produce meat more economically than any other dairy or beef breed animal and resulted in meat which is more desirable to the consumer. Because of their greater efficiency they had an Economic Shipping Weight of 1050 lb. as opposed to 900-950 lb. for beef breed animals. There was, however, a certain risk involved in their production because of the wide variation in the grades they may receive. / Business, Sauder School of / Finance, Division of / Graduate