Search

In the sterilizing process in the manufacture of evaporated milk, it is desirable to produce an incipient coagulation, in the nature of a tender jell or "fiver" as it is called by the practical men. Such a product will have a heavy creamy body after the "fiver" has been broken up by the shaking process. This is desirable because the product presents a richer appegrance to the consumer, and on account of the greater viscosity, there is little danger of fat separation from such a product. However, evaporated milk differs widely in the readiness with which it coagulates. At times the milk coagulates so readily that it would be unmarketable, on account of its curdy appearance, if it were heated long enough to preserve it. This constitutes the problem with which we are concerned in this paper. There is probably no condensery that is entirely free from this trouble throughout the year. I t is undoubtedly one of the biggest problems that confronts the industry.

Summary 1.Further studies on urea utilization in the rumen fistula heifer are reported. 2.With timothy hay as the sole ingredient of the basal ration, utilization of added urea took place only partially, if at all. In the presence of starch a suitable substrate was provided for the development of an active flora and urea was efficiently utilized. 3.When casein was added to a timothy hay-starch-urea ration the utilization of urea was markedly reduced.

Summary 1.The serum of winter produced milk showed physical characteristics at variance with that of summer produced milk. It was clarified with greater difficulty. An adjustment of the salt balance and pH improved somewhat the technique used for the preparation of the serum from winter milk. The time at which these changes occur varies from year to year. 2.The serum of winter produced milk showed lower nutritive value than that of summer produced milk as measured by its use in supplementing a highly purified diet as a source of the vitamin B complex. 3.The significance of these studies lies in the relation of fresh plant tissue as contrasted with field dried material to subtle changes in the milk secreted.

Summary Goats receiving trace-mineralized salt (containing cobalt), in comparison to those receiving only iodized salt, were observed to have a higher level of vitamin B 12 in their colostrum and milk during the first week post-partum. Trace-mineralized salt or a 50-mg. supplement of cobalt per goat per day had no influence upon the level of this vitamin in the goat's milk after this time. The addition of trace-minerals to the diet of the goat did not influence the free folic acid level of the goat's milk. The lower folic acid content of goat's milk observed in this study is believed to be more accurate than the previous data of Collins et al . (1).

Summary 1.The effect of moisture level and temperature on carotene losses in dehydrated alfalfa and cereal grasses was studied under sealed conditions. The moisture levels studied were 2.5 to 15 per cent and the temperatures employed were 22 to 25° C. and 33 to 36° C. 2.In most instances, almost complete carotene preservation resulted with 10 to 15 per cent of water. Preserving both the carotene and the green color was best accomplished at 7.5 to 10 per cent of water with 10 per cent as the preferred level because of the more optimum carotene preservation with no detrimental color change. At 7.5 per cent of water, the amount of loss was unpredictable and varied from 2.5 to 17 per cent. The losses increased with decreasing water levels below 7.5 per cent and at 2.5 to 5 per cent varied from 5 to 32 per cent. 3.Storage at 22 to 25° C. (room temperature) was more favorable for the preservation of the green color at 10 to 15 per cent of water level than storage at 33 to 36° C. Little difference in color preservation was observed at either temperature with the moisture below 10 per cent. Postitive pressures seldom were observed with 10 per cent moisture or less and storage at 22 to 25° C. 4.Storage under sealed conditions at 33 to 36° C. of a mixed feed containing 15 per cent alfalfa as the main source of carotene resulted in complete carotene retention with 10 per cent of moisture. Below 7.5 per cent the losses were large. The feed became bleached in the unwaxed carton but retained a pleasant aroma. In waxed eartons feed at any moisture level remained green and had pleasant aromas. 5.Where the mixed feed contained the added trace elements Fe, Cu, Mn and Co, the contents of the unwaxed carton were bleached and also possessed a rancid or tallowy odor. Under sealed conditions the green color and fine aroma were retained, and at 10 per cent and above of water, the carotene was preserved completely. 6.Investigation of many materials as barriers to oxygen and carbon dioxide transmission finally led to the use of Saran, a plastic film. It was found effective for the preservation of carotene in dehydrated alfalfa, with a proper water level.

Summary Butterfat prepared from butter made in various months of the year has been fractionated into two fractions by cold crystallization from an acetone solution. A liquid fraction obtained from September, 1945, butter allowed rats to grow at a superior rate, while a solid fraction prepared from this butter caused a very slow rate of growth. This phenomenon was not repeated to the same degree in subsequent trials using other samples of butter. Corn oil was separated into two fractions by a similar procedure but rats grew equally well when fed either of these fractions or corn oil itself. The treatment of either fat by solvent had no deleterious effect on its nutritive value.

Summary The addition of urea as a source of nitrogen definitely increased the synthesis of riboflavin, nicotinic acid, biotin and pantothenic acid in the bovine rumen when a readily available carbohydrate was present. Pyridoxine and “folic acid” could not be too closely correlated with ration composition. In the absence of a readily fermentable carbohydrate and probably a low population of microorganisms the synthesis of the members of the B complex is not at a maximum. The data indicate that thiamine may not be synthesized in the rumen. However, it seems more than probable that it is synthesized, but absorbed or destroyed at a rate greater than its synthesis.

Studies on the comparative nutritive value of butter fat and certain vegetable oils (1) showed that butter fat homogenized into raw skimmed milk with ample fat soluble vitamins and minerals added and fed ad libitum to weanling rats gave better growth than did corn oil, coconut oil, cottonseed oil, and soybean oil fed in a like manner. Further study disclosed that the factor (or factors) responsible for the superior growth of rats on butter fat milk did not lie in the non-saponifiable fraction of butter fat (1), nor did such compounds as egg lecithin, sphingomyelin, sphingosin, or ethanol amine have any effect on the nutritive value of the vegetable oils used in our experiments. Choline was also tried and showed slight growth promoting effects on the females (2). Later experiments (unpublished) have shown that the addition of choline (30mg. per day) has had no growth promoting effect when added to butterfat or any of the vegetable oils fed in skimmed milk.

Summary Twenty-nine samples of plant products including hays and grains were assayed for thiamine, riboflavin, biotin, nicotinic acid and pantothenic acid. These samples were stored in the dark at 20–25° C. for one year, ground and unground, with no apparent loss of the vitamins mentioned above.

Summary 1.Further studies on urea utilization in a rumen fistula heifer are reported. 2.With timothy hay as the sole ingredient of the basal ration utilization of urea was low. Corn molasses provided a suitable substrate for the development of an active flora, and urea was fairly well utilized. The protein of the rumen contents (dry basis) rose from a basal level of 7.7 per cent to 9.28 per cent. 3.With timothy hay, starch, corn molasses and urea as the ration the protein level in the rumen contents rose from 7.7 per cent to 10.9 per cent. Apparently somewhat better utilization of urea was made on a starch-containing ration than on one containing mainly a more soluble sugar. 4.In growth experiments with young heifer calves a ration made of timothy hay, cane molasses and urea fortified with common salt, bone meal, and vitamin A gave a subnormal rate of growth (0.6 to 0.8 pound daily). 5.When this ration was supplemented with 0.3 pound of crude casein daily normal growth was attained. Substitution of an equal weight of corn starch for the casein likewise resulted in normal growth. 6.For maximum growth of calves a ration made of a roughage, molasses and urea must be supplemented with some additional source of a more insoluble but fermentable carbohydrate or insoluble protein which can be drawn from the cereal grains or concentrates, such as the oil meals. In our limited experience this supplemental material need not be more than 3−5 per cent of the total ration.

Summary 1.Two separate experiments involving the utilization of urea and ammonium bicarbonate nitrogen with 10 growing calves have been conducted. 2.The experiments indicate definitely that such nitrogen can be used for at least a partial supply of protein nitrogen. The most probable explanation is the production of protein by bacterial cell multiplication in the rumen and later digestion in the fourth stomach and intestine. Apparently most efficient utilization occurs when some soluble sugar such as corn molasses is fed in the ration. 3.With urea nitrogen constituting 43 per cent of the nitrogen of the ration the growth rate was but slightly less than that secured with a ration containing 66 per cent of its nitrogen as casein nitrogen. This does not imply that urea nitrogen in the ration used is superior to casein nitrogen. 4.Where casein nitrogen constituted 43 per cent of the total nitrogen of the ration, as in the case of animal No. 2, the growth rate over a period of 16 weeks was 1.5 pounds daily as compared with 1.3 pounds daily for the comparable level of urea nitrogen. 5.The nitrogen of ammonium bicarbonate was also utilized. 6.Analysis of the tissues at the end of the experiment indicated that the increments in weight with urea or ammonium bicarbonate nitrogen were of normal composition with a protein content similar to that of the casein fed animal. Extractable non-coagulable nitrogen was no greater in the leg tissues of the urea or ammonium bicarbonate animal than in the tissues of the casein animal.

Summary 1. The rate of carbon dioxide production and oxygen consumption by dehydrated alfalfa and cereal grasses under sealed conditions was studied at moisture levels of 10–25 per cent. The rate of respiration increased as the level of moisture and the temperature were increased. The extent of carbon dioxide production and oxygen consumption was variable with time at a given moisture level. 2. The rate of carbon dioxide production in a dehydrated alfalfa with 10 per cent of total water is less than one-third the rate observed when the product contains 20 per cent of total water. 3. With 10 per cent or less of total water, the rate of carbon dioxide production and oxygen consumption generally is too slow to insure complete carotene preservation under sealed conditions. The carotene losses may vary from 5–30 per cent during storage at room temperatures of 22–25° C. for 3 months. With 12.5 per cent of total water under sealed conditions for 3 months, both products (alfalfa, Heil Drier, and alfalfa, Fulmer Drier) retained completely their carotene content as well as their green color.

Summary 1.Cobalt deficiency, characterized by unthriftiness and anemia, has been observed in cattle in Northeastern Wisconsin. 2.This deficiency was corrected by the feeding of salt containing one ounce of cobalt sulfate (CoSO 4 · 7H 2 O) per 100 pounds. When this salt mixture is incorporated into the grain at a level of one per cent, it will supply about 3mg. of elemental cobalt per day when five pounds of grain are consumed. Good results were also secured by the daily feeding of one teaspoonful of a solution made by dissolving one ounce of either cobalt sulphate or cobalt chloride in one gallon of water. 3.The normal range of the hemoglobin level of calves, heifers, and cows was 9.5 to 12.5 grams per 100 cc. of blood. 4.The tolerance for cobalt in this species was high. Feeding as much as 50mg. of cobalt per day produced no polycythemia.

Summary 1.Destruction of the lipoxidase by autoclaving for 1hour at 15 lbs. pressure did not preserve the carotene content of dehydrated alfalfa or cereal grasses exposed to air at room temperature. 2.The addition of 5 to 10 per cent of water to these dehydrated materials and then lightly packing them in receptacles sealed with flexo wax or Durex wax preserved the carotene completely for 3 months, when held at room temperature (22–25° C). The total water content for the oats was 15–20 percent and for the alfalfa 12–17 percent. 3.The process of preservation appears to be a restoration of more rapid respiratory enzyme action with utilization of the oxygen and formation of carbon dioxide. There was no indication that bacterial action directly was responsible for the changes that occurred. Temperature changes during the process of respiration were negligible in the masses of material used. 4.It is evident that receptacles with minimum or no air and CO 2 effusion rates are necessary for success in the preservation of the carotene by the method outlined. Oxygen must be excluded or at least held at a low concentration. This phase of the problem is under further study.

Summary 1.Evidence is presented through "in vitro" experiments that conversion of inorganic nitrogen to protein can occur through the use of bacteria from the cow's rumen. 2.Bacterial activity, and hence conversion, is dependent on the pH of the media, the optimum range being 5.5 to 7. 3.The carbohydrates used in the media were of equal efficiency in influencing conversion, with the exception of cellulose which was not an acceptable carbohydrate for these studies. 4.NH 4 HCO 3 is as efficient as urea in the rate of utilization by rumen organisms. 5.The decrease in NH 3 can be accounted for by an increase in protein nitrogen. 6.The level of protein in the media has a negative influence on the decrease in NH 3 - N. 7.Amylolytic activity of rumen liquid has been demonstrated, with only slight activity in the saliva itself. 8.Proteolytic activity of cow's saliva is absent.

Summary Simple home-grown rations proved to be adequate for growth in dairy heifers. Alfalfa hay, corn silage, and a mixture of equal parts corn and oats produced excellent gains. The rate of growth was not improved by the addition of bone meal or wheat bran. Timothy hay, corn silage, and corn and oats furnished too little protein for optimum growth. The simple addition of protein from corn in the form of corn gluten meal promoted as rapid growth as was obtained by using a mixture of greater variety including wheat bran, linseed meal, and corn gluten meal in addition to corn and oats.

Summary Rats started on experiment in October and grown on mineralized raw milk and mineralized pasteurized milk showed no differences in growth or development over a period of 30 weeks. The average daily gains during the first six weeks for rats on mineralized raw milk were less for the animals started in April than those started in October. In April the rate of growth for rats on pasteurized milk was inferior to that obtained on raw milk. A decrease was observed in the daily rate of growth in male rats on mineralized milk from 19gm. for milk produced in October to 3.32gm. for milk produced in December to 2.45gm. for milk produced in February. The decrease for male rats on pasteurized milk for the same periods was 3.90 to 1.96 and to 1.14gm. The female rats showed some decrease in growth on winter milk but the impairment in. growth during this period was not nearly as great as that, observed in the case of the male rats. The kind of feed ingested by the cow has a greater effect upon the nutritive value of milk than does pasteurization. Pasteurization has practically no detrimental effect, as measured with rats, upon the nutritive value of a milk of high nutritive quality but may further decrease the value of a milk of low nutritive quality.

Summary 1. Twenty-four Holstein cows were involved in a study of the possibility of substituting urea nitrogen for linseed oil meal nitrogen in milk production. Fifteen of the cows completed a lactation on each of the basal, urea, and the linseed meal rations. Six of the cows were involved in a study of the effect of corn molasses on urea utilization. Each completed a lactation on a urea, a urea-molasses, and a urea ration. 2. On the basal ration the protein level in the concentrate mixture was about 10 per cent. With the added urea or linseed meal it was 18 per cent protein equivalent. Timothy hay and corn silage constituted the roughage. 3. In milk production some cows led on the linseed meal ration while others led on urea with average differences favoring linseed meal in too small a degree to be statistically significant. On the basal ration, with its lower protein content, less milk was generally produced than on either of the other two rations and the cows failed to keep up their live weight as well as on either the linseed meal or urea rations. It appears that with this species and a suitable ration in respect to carbohydrate content, urea can function as a source of nitrogen as effectively as can oil meal. 4. In respect to weight of calves and breeding history, one ration appeared as efficient as the other. 5. The composition of the milk, the flavor of the milk, and the composition of the blood were not different on the two rations. 6. There was no sustained and positive evidence that molasses feeding on a grain ration improved the utilization of urea. With the starches of the grains available, sugar is rapidly produced in the rumen and serves as a suitable substrate for the organisms. 7. Urea (46 per cent nitrogen) should not be fed at a rate greater than about 1 per cent of the dry matter of the ration or 3 per cent of the concentrate mixture. In dairy sections where hay, silage, and home grown grains are available, a suitable nitrogen level in the concentrate mixture can be secured by the addition of 3 pounds of urea to 97 pounds of the grain mixture.

Summary 1. A comparison of the composition, of rumen contents and the ration fed in respect to dry matter, fiber, ether extract, ammonia nitrogen, non-protein nitrogen and total nitrogen has been made. 2. The level of total nitrogen and fiber found in the rumen material is distinctly higher than in the ration fed. 3. The level of total nitrogen (protein nitrogen) and crude fiber found in the rumen content increases slightly in the time between feeding, indicating a more or less selective removal of nitrogen-free extract due to its breakdown by bacteria or bacterial enzymes and its passage out of the rumen. 4. Urea nitrogen or ammonia nitrogen when ingested as 1 to 5 per cent of the dry matter of the ration disappeared from the rumen in 4 to 6 hours after feeding. Evidence for its conversion to protein nitrogen is presented. 5. A definite increase in the percentage of protein nitrogen of the rumen ingesta was produced by adding 5 per cent urea to a low nitrogen basal ration.

Summary September butterfat (1947) again was fractionated by crystallization from acetone at −5° C., yielding a liquid fraction (II) which allowed rats to grow at a superior rate as compared with butterfat or corn oil, and a solid fraction (I) which gave a significantly slower growth rate.

Summary Data have been secured on the effect of feeding 15 g. of iodinated casein daily to eleven dairy cows for varying periods of time and under various conditions. Increases in milk and butterfat production were obtained. All cows lost weight and had increased heart rates. Night-morning milk composites were obtained at 2- and 3-week intervals during the experimental period and analyzed for fat, total solids, skim milk nitrogen, casein nitrogen, non-protein nitrogen, urea and ammonia nitrogen, and vitamin C. Decreases of 30 to 63 per cent in vitamin C and of 20 to 40 per cent in urea nitrogen and a maximum decrease of 0.05 per cent (0.32 per cent protein) in the skim milk nitrogen were found. Blood samples were taken, concurrently with the milk samples and analyzed for total nitrogen, plasma nitrogen, non-protein nitrogen, urea and ammonia nitrogen, vitamin C, and per cent cells. Blood urea nitrogen decreased. The duration of response varied from 6 to 15 weeks, after which a marked drop in milk yield occurred after iodinated casein feeding was discontinued. Age and breed differences in response were noted. The limitations of iodinated casein for commercial usage are discussed.

n/a

Summary 1. The protein content of rumen ingesta showed a decided increase when the level of protein in the concentrate fed was increased to 24 per cent. 2. The rate of conversion of urea nitrogen to protein in the rumen decreased as the protein level of the rumen ingesta became greater than 12 per cent. 3. When the level of protein in the concentrate fed was increased to more than 18 per cent the rate and extent of conversion of added urea nitrogen to protein began to decrease. 4. When no linseed oil meal was added to the basal grain mixture (11.3 per cent protein), the added urea was utilized up to a level of 4.5 per cent (protein equivalent of 12 per cent) of the grain mixture.