Pounds Of Milk Research Articles

Título en español.

Veinticuatro vacas cruzadas con sangre Holstein, las cuales produjeron diariamente no menos de 30 libras de leche durante un período preliminar de 30 días, se sometieron a dos tratamientos: 1, El tratamiento testigo que consistió en pastoreo en yerba Pangola debidamente abonada, suplementada con un alimento comercial con un 20 por ciento de proteína bruta; y 2, el tratamiento experimental que consistió en confinar las vacas y alimentarlas a discreción con una ración completa con un 22.5 por ciento de bagazo de caña molido y un 77.5 por ciento de concentrados, minerales y un suplemento vitamínico. Durante el período preliminar, las vacas testigo y las que se sometieron a un tratamiento experimental produjeron diariamente un promedio de 42.9 y 40.1 libras de leche, respectivamente. Las cifras correspondientes al período de comparación fueron las siguientes: Durante los primeros 30 días de dicho período, cuando ocurría la lactación máxima, 43.8 y 42.0 libras; durante los siguientes 175 días, cuando ocurría un descenso en la lactación, 35.3 y 31.6 libras; y durante el período completo de los 205 días, 36.5 y 33.1 libras, respectivamente. Ninguna de las diferencias entre los tratamientos fue significativa estadísticamente al ajustar los datos mediante el análisis de covarianza, cuando se usaron los datos del período preliminar como variable independiente. Las vacas del grupo bajo el tratamiento experimental consumieron diariamente un promedio de 36.1 libras de la ración completa y necesitaron 1.09 libras de esta ración por cada libra de leche que produjeron. El contenido promedio de proteína fue significativamente (P < .01) mayor en la leche de las vacas bajo el tratamiento experimental que en la del tratamiento testigo (3.55 contra 3.18 g./100 ml.). Los promedios en cuanto al porcentaje de grasa en la leche fueron 3.07 y 3.28, y en cuanto a los sólidos-no-grasos 8.33 y 8.34, bajo los tratamientos testigo y experimental, respectivamente. La ganancia diaria promedio en peso vivo fue de 0.52 y 0.56 libra en las vacas de los grupos bajo los tratamientos testigo y experimental, respectivamente. Basándose en un costo de $3.58 y $4.41 por cada 100 libras de la ración completa y la mezcla comercial de alimento concentrado, respectivamente y $0.34 por cabeza por día de pastoreo, y en un ingreso de $7.80 por cada 100 libras de leche producida, se hicieron los siguientes estimados bajo los tratamientos testigo y experimental, respectivamente: Costo total de la alimentación por vaca por día, $1.16 y $1.29; ingreso diario por concepto de la leche producida, $2.85 y $2.58; ingreso después de deducir el costo de la alimentación, $1.69 y $1.29; y costo de la alimentación para producir 100 libras de leche, $3.18 y $3.90. En cuanto a las respuestas de las vacas en términos de producción no se encontró evidencia en contra de la hipótesis de nulidad, de que el tratamiento bajo evaluación no era superior al tratamiento testigo. A pesar de que no se obtuvieron suficientes datos sobre costos e ingresos para analizarse estadísticamente, los promedios favorecieron el tratamiento testigo. Los resultados enf atizan la indispensabilidad de obtener un alto promedio de producción de leche (por lo menos 40 libras diarias por vaca) para que la ración completa pueda competir en términos económicos.

Dairy Herd Improvement Association Herd Averages. III. Characteristics of Herds at Different Production Levels

A total of 8,048 yearly herd average reports from Holstein Dairy Herd Improvement Association herds in 23 states was studied to evaluate the characteristics of herds at various levels of milk production. Separate intra-county least-squares analyses were made for the years 1960–64. Herd average per cent days in milk, grain feeding, silage feeding, feed cost per hundred pounds of milk produced, fat yield, income over feed cost, grain cost, and total feed cost differed significantly among production levels. There were marked positive trends in per cent days in milk, grain feeding, and income over feed cost. It was concluded that estimates of grain feeding are useful but that forage estimates are of little value, due to the large errors in their measurement. Results indicated that gross means of herd averages provide a reasonably accurate assessment of the characteristics of herds at different levels of production.

Large Herd Management in the South and Southwest

Because of inflation, decreasing profit per unit, and specialization there has arisen a need for large herd management in the South and Southwest. The manager of the large herd is faced with a multitude of problems encompassing labor, feed, disease, climate and, above all, profit. Today in this area, the problem of labor-quality and quanti ty--is foremost in the mind of management. More and more time is being spent dealing' with the different aspects of labor management. Total pounds of milk per man and number of animals per man are some of the comnmn denonfinators used in labor management decisions. More capital is required to utilize labor effectively. Like all large agricultural businesses, the dairies in the South and Southwest have been affected by the Federal Wage and Hour Law. There appears to have been little change in labor costs, because managers of most of the large herds pay substantially more than the one dollar an hour. In the Knolle operation, the minimum wage law has made us realize more fully the costs of equipment breakdowns and employee tardiness and has made us more efficient in labor usage. Feed requirements. The second major concern to management is the herd feed requirement. In much of the South and, especially in the Southwest, drought conditions exist much of the time. The average rainfall varies in different regions between 6 and 40 inches. The old saying, When it rains, it pours, applies to the Gulf Coast, where most of the rain is unevenly distributed. Irrigation is used where underground or river water is available. This increases the cost per ton of feed, but is partially offset by the availability of a green crop much o£ the year. Cotton and milo are predominant crops in the region and provide a cheap source of protein and roughage through cottonseed meal and hulls, milo grain, and gluten feed. Roughages grown include the hybrid sorghum Sudans, corn (mainly in the South), and alfalfa (in the upper Southwest). Coastal Bermuda and Midland Bermuda comprise the pasture land because they make excellent permanent pasture when skilled management is employed. In addition to the common feeds, most large herds utilize carrots and citrus pulp when available. These products constitute an inexpensive source of roughage and increase the pounds of milk per cow. A new feed on the market is alfalfa cubes from New Mexico. Cubes decrease labor costs and lower waste by eliminating grinding. Irrigation, longer growing season, and the availability of feed byproducts give this area a great advantage in total feed costs per pound of milk. Weather effects. Changeable weather conditions in the Southwest hinder milk production. Hot, humid conditions characterize the Coastal Bend section. Dry, semi-arid conditions prevail in the upper Southwest, where irrigation is necessary to produce a crop. In both of these areas rapid weather changes occur which affect both production and labor. In Texas the morning may be beautiful, the afternoon dusty, and the evening may bring a snow storm. The temperature seldom goes above 105 F along the Coast, but rises to 110 F further inland. Because of short winters, few free stall housing installations are being built in the region and the cost of housing per cow is kept at a minimum. Shade, windbreaks, and warm and cool drinking water are aids in coping with effects of climate on cattle. Disease problems. Due to the larger herds' using dry lot dairying, diseases are a major concern to management. Cows are subjected to more confinement and receive less individual attention. In the Southern region where hot, humid conditions prevail, brucellosis, leptospirosis, internal parasites, and flies exist. As numbers of cattle increase, hazards of disease and the importance of immunization are increased. Immunization increases costs, but is essential. Diseases are not as prevalent in the semi-arid regions. Profits and management. Profit is the chief factor in any dairy enterprise. The successful manager must have a good business background and some practical experience. Breeding decisions, such as whether to raise replacements relying on proven sires or to buy them, are of most importance. The large herd manager in the South and Southwest must plan for the future and try to stay three years ahead of problems. As one authority said, I f you are doing things today like you did just five years ago, then there is a 50-50 chance that you are doing them wrong. As a good businessman

QUALITY CONTROL PROGRAMS OF MILK MARKETING COOPERATIVES IN THE UNITED STATES

Summary Replies were received from 63 of 123 cooperatives surveyed. The smallest cooperatives were located in the Western region and the largest in the North Atlantic region. There was no relationship between the size of the organization and the number of fieldmen employed per 100 members or per million pounds of milk produced. Of the 57 cooperatives employing fieldmen, 45 reported that 50% or more of their fieldmen's time was devoted to raw milk quality problems. Opinion was divided about equally as to whether raw milk quality problems should be the responsibility of the cooperative, or jointly of the plant, the cooperative, and the regulatory agency. A great diversity was found in the frequency and method of evaluating raw milk quality by the cooperatives. Eighteen basic types of tests were used, with tests for inhibitors and total bacteria counts being the most popular.

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Pelleted Coastal Bermudagrass, Pelleted Whole Stalk Corn, and Ground Whole Stalk Corn with High and Low Concentrates for Lactating Dairy Cows1

AbstractFollowing field drying, mature whole‐plant corn containing 32% grain on a dry matter basis was harvested and ground through a hammer mill. A portion was pelleted using 3% molasses as a binder. Because ground unpelleted material was extremely dusty, it was mixed with 20% molasses. Coastal bermudagrass was harvested at 3 weeks of age, dehydrated, and pelleted. In a continuous‐type experiment with 2 replications and 36 cows, the forages were each fed with a high and a low concentrate level for 8 weeks. The concentrates were fed at grain to FCM ratio of 1:5 and 1:2.5. Protein contents of the concentrates were adjusted to equalize intakes and to meet the requirements of the cows. Each cow received 3 pounds of long hay daily. Cows fed ground corn, corn pellets, and coastal pellets produced 29.7, 28.5, and 29.4 pounds of milk per day, respectively. Forage dry matter consumption was 31.2, 28.2, and 32.9 pounds per cow per day for the three forages. Milk composition percentages were: fat, 3.93, 3.62, and 3.80; protein, 3.66, 3.52, and 3.69; and SNF, 8.97, 8.85, and 8.93. Only the differences in fat and protein were significant. Cows fed the high level of concentrates consumed 3.3 pounds less forage dry matter but ate 2.1 pounds more total dry matter. Milk production was 1.0 pound higher for those fed the high level of concentrates but milk composition was not affected. It was concluded that each of the forages was a satisfactory feed and that they were essentially equal.

Energy and Protein Requirements of Milk Production

The currently recommended allowances of total digestible nutrients (TDN) and digestible protein (DP) for milk production and their bases were examined. It was concluded that the uncertainties of estimating the body gain or loss of energy and protein from body weight changes preclude the use of the conventional feeding trial to estimate requirements. As a consequenee, in the present studies the milk production requirements for TDN were estimated by the digestion-trial method and those for DP from published nitrogen-balance data.The TDN values of seven diets ingested at levels of intake ranging from one to five times the maintenance level were determined in 265 individual-cow trials. Per increment of intake equivalent to that of maintenance, the TDN value of the diets declined at rates ranging from 2.1 to 6.2% (average rate, 4.0%). These data indicated that the requirements for TDN (determined at maintenance) increase with increasing feed intakes (or milk outputs). Accordingly, the TDN requirements were computed for the average rate (4%) of depression in the TDN value observed.An examination of nitrogen-balance data indicated that the average rate of utilization of DP for the combined functions of milk production and maintenance of cows in body nitrogen equilibrium is of the order of 65%. This observation suggests that milking cows require an average minimum amount of DP in the diet equivalent to 154% of the quantity of protein in the milk. For usual 4% FCM, the requirement would be 24.4g of DP per pound of milk. Since the DP value declines at about the same rate as the TDN value of the diet with increasing daily inputs of feed, the effect of feeding level was superimposed on the apparent net requirement for DP. This indicated that for cows in nitrogen equilibrium, the requirement would range from 25.3 to 30.0g per pound of 4% FCM for daily yields of 10 and 100lb, respectively. The data also suggest that milk production requires a DP:TDN ratio of 1:5.7.Practical feeding requires a knowledge of a) the dietary needs of the various body functions and b) the nutritive values of feeds. Although nutrient requirements are the basis of practical allowances, a number of conditions need to be taken into account to adapt net requirements to practical feeding situations. Thus, it is necessary to generalize and, in certain instances, to project generalizations, even over gaps in present knowledge.In this report it is the intent a) to summarize the present status of the knowledge of the energy and protein requirements of lactation and b) to extend results of the authors’ recent studies to derive estimates of the energy and protein requirements.

Comparison of Simple vs. Complex Concentrate Mixtures for Dairy Cattle in Puerto Rico: Feeding Lactating Cows Receiving Fair-Quality Forage

A double-reversal experiment with 80-day periods, extending from day 26 to day 265 of lactation, was conducted with 2 groups of 10 cows each. The two treatments consisted of two different concentrate mixtures, one of which had a simple formula consisting of ground shelled corn, soybean-oil meal, fortified molasses, bonemeal, and salt, and was prepared at the Substation, while the other was a complex mixture obtained from a commercial source. Both mixtures contained nearly the same level of crude protein. Concentrate allowances were based upon the Maryland Standards. The remainder of the ration consisted of a moderate amount of sorghum silage, or occasionally green chopped grass, and low-quality pasture. The simple-concentrate mixture proved to be more palatable than the complex mixture. The lactational response obtained with the simple mixture as compared with the complex mixture was significantly (P < 0.01) greater in production of milk uncorrected for fat content, 28.2 vs. 27.1 pounds per day, though not significantly different in production of 4-percent fat-corrected milk nor in production of milk fat. The efficiency of utilization of the simple mixture was significantly, P < 0.05, better for the production of milk uncorrected for fat content, 55.3 vs. 56.8 pounds of concentrates per 100 pounds of milk produced, but not significantly better for the production of 4-percent fat-corrected milk. The cost of concentrates per 100 pounds of milk produced was $2.34 for the simple and $2.67 for the complex mixture. It is concluded that, under conditions of the present experiment, in which forage was limited in quantity and of only fair quality, a simple concentrate mixture formulated to supply digestible energy at a minimum cost is just as adequate nutritionally for lactating cows as a concentrate mixture containing a multitude of different ingredients and supplemented with minerals, vitamins, and antioxidants. It is further concluded that the use of such simple concentrate mixtures prepared at the dairy farm will result in a reduction in feeding costs, provided the operation is large enough to offset the cost of the required machinery. A possible alternative would be the commercial preparation by feed mills of simple concentrate mixtures which could be sold to dairymen at a lower price than the present complex commercial mixtures.

Effect of Feeding Different Roughage Levels and Sodium Acetate in High-Grain Rations on Milk Production, Milk Constituents, and Rumen Volatile Fatty Acids

Summary Two trials, ten animals in Trial 1 and 12 animals in Trial 2, were conducted to study the effect of feeding program on milk production, milk constituents, and rumen volatile fatty acids. A switchback design was used consisting of 7-wk periods, 3-wk changeover periods, and 4-wk comparison periods. Treatments in Trial 1 were (1) 10lb pineapple bran plus concentrate, (2) Treatment 1 with 2.91% sodium acetate in concentrate, (3) 12lb pineapple bran, 50lb chopped Napier grass and concentrate. Treatments in Trial 2 were (1) 10lb pineapple bran plus concentrates, (2) Treatment 1 with 2.83% sodium acetate in concentrate, (3) Treatment 1 with 5.66% sodium acetate in concentrate. Data from cows in Trial 1 on Treatments 1, 2, and 3, respectively, were: 4% FCM 35.35 a , 37.13 a , and 39.74 a lb; milk fat 2.79 a , 2.94 a , and 3.79 b %; total solids 11.05 a , 11.10 a , and 12.44 b %; SNF 8.22 a , 8.16 a , and 8.45 b %. In Trial 2, the values for Treatments 1, 2, and 3, respectively, were: 4% FCM 30.30 a , 32.85 b , and 34.17 e lb; milk fat 3.42 a , 3.96 b , and 4.18 b %; total solids 11.94 a , 12.49 b , and 12.63 b %; SNF 8.50 a , 8.50 a , and 8.43 a %. Values in the same category with different superscripts are significantly different by Duncan's multiple range test. No significant differences were observed in pounds of milk produced daily and body weight change in either trial. Rumen fluid from cows on Treatment 3 in Trial 1 contained significantly more acetic and less propionic, valeric, and longer-chain acids than from cows on Treatment 1.

Effect of Incomplete Milking on the Incidence of Udder Irritation and Subsequent Milk Yield of Dairy Cows

Summary Incomplete milking of dairy cows was practiced for ten-day periods to determine its effect on udder irritation and subsequent milk yield. Two or four pounds of milk were left in the udders at each milking. One group of cows was free from all mastitis infections, whereas most of the cows in the second group had persistent mastitis infections other than Streptococcus agalactiae . Each ten-day incomplete milking period was preceded and followed by a seven-day normal milking period. Leaving 4lb of milk in the udder at each milking resulted in a greater permanent reduction in milk yield than did leaving 2lb in the udder. The leucocyte counts, Whiteside ratings, and CMT ratings did not increase during the periods of incomplete milking. The cows with persistent mastitis infections showed higher values for all three indicators of udder irritation than cows free from infections.

Effects of Gastrointestinal Parasites on Cottontails

Twenty pairs of cottontail rabbits (Sylvilagus floridanus) were kept in large, outdoor pens under seminatural conditions. One-half of these animals were treated with anthelmintic and coccidiostatic drugs in an attempt to reduce gastrointestinal parasites. The remaining animals served as untreated controls. Numbers of gastrointestinal coccidia and round worms were reduced 51 percent and 46 percent in the treated group. The treated group produced significantly more young (48 percent) than untreated controls. There was no significant increase in body weight in the treated animals. When data for both treated and control groups were combined, there was a significant association of low worm burdens with greater weight gains. Fluctuations in nematode parasitism of treated animals were similar to those observed in control animals but occurred at lower values. This observation suggests that worm populations are controlled by environmental factors. This study constitutes one phase of a project on the effects of certain parasites and diseases on cottontail rabbits. This paper describes certain effects of subclinical infection by gastrointestinal helminths and coccidia on reproduction and changes of body weight. The degree to which parasites in natural infections reduce the vitality of hosts living in the wild is a matter of conjecture. Most reports indicate that subclinical infections are the rule and clinical infections are the exception. Clancy et al. (1940), in a survey of Connecticut cottontail (Sylvilagus floridanus and S. transitionalis) parasites, found that half the rabbits showing signs of malnutrition had more species of parasites than did animals. Lechleitner (1959) concluded that Eimeria sp. under normal environmental conditions had little effect upon black-tailed jackrabbits (Lepus californicus). When the rabbit population was concentrated by a flood, clinical coccidiosis with deaths resulted. Controlled experiments with sheep (Herlich 1958), chickens (Reid and Carmon 1958), and cattle (Shelton 1956; Davis et al. 1959, 1960) have established that heavy parasitic burdens resulted in decreased host-weight gains. In unpublished data, A. C. Todd (Personal communication 1961) found that reduced helminthiasis in heifers during the first lactation resulted in significantly higher daily averages of total pounds of milk produced and in higher total pounds of butterfat. I attempted to carry out cottontail experiments of a design similar to that often used in parasitological experiments of domestic animals. Orrin Rongstad is acknowledged for assistance in the field. This study was conducted during the tenure of a Wisconsin Alumni Research Foundation Fellowship. Funds and facilities for this project were furnished by the Department of Veterinary Science and the Department of Forestry and Wildlife Management of the University of Wisconsin. MATERIALS AND METHODS Twenty pairs of cottontails from southern Wisconsin were placed in 20 outdoor pens measuring 26 x 60 feet each. The pens were arranged in two rows of 10 each, separated by a dirt roadway. While the pens in each row had common sides, the sandy soil and dense vegetational cover prevented nearly all drainage of surface water from one pen to another. The vegetation in the pens was mainly mixed

Physiological Responses of Lactating Dairy Cattle to Pelleted Corn and Oats

Summary The physiological effects of feeding pelleted corn and oats at 19.75, 35, and 49% of the total ration of dairy cows was investigated. Molar ratios of volatile fatty acids (VFA) in rumen fluid were affected significantly by feeding rations containing 35 and 49% of pelleted corn or oats but not by rations containing 19.75% of these pelleted grains. Milk fat per cent and energy per pound of milk was depressed by 35 and 49% pelleted corn rations but not by the 19.75% pelleted corn or by any of the pelleted oat rations. The relationship between rumen VFA ratios and milk fat are discussed in the light of current knowledge.

Udder Capacity Estimates as Affected by Rate of Milk Secretion and Intramammary Pressure

Summary An extra-period Latin-square design balanced for sequence effects, with four groups of five Jerseys each, was used to study udder capacity. A group of five Brown Swiss provided aditional information. Experimental intervals were 8, 12, 16, 20, and 24 hr. in length. The intervals prior to the 8-, 12-, 16-, and 20-hr. experimental intervals were 6, 2, 8, and 4 hr., respectively, and thus too short to affect the experimental results. The 24-hr. interval had preceding intervals of 8, 12, 14, 16, 20, and 24 hr., but they produced no significant effect on total pounds of milk. Sequence effects were not significant. Oxytocin (20 I.U.) was injected before and after each experimental interval to eliminate residual milk effects. From these data, estimates of udder-holding capacity and capacity to secrete against the intramammary pressure and/or the toxin-like action of accumulated milk were obtained. With increasing milking intervals the total pounds of milk increased asymptotically for all groups. The estimated theoretical udder capacities for the five groups of animals in this study were 42.4, 49.9, 55.8, 51.3, and 63.2 lb. of milk. Thirty-five hours was the estimated length of time before milk secretion approached zero. Increases in total milk caused increases in intramammary pressure. With increases in milking interval, total milk, and/or intramammary pressure, both the average and instantaneous secretion rates declined.

Effect on Milk Production of Chopping Meadow Crop Once and Twice Daily

Summary The effect of cutting alfalfa-bromegrass once vs. twice daily for milking cows was compared over a 111-day feeding period. Treatments consisted of three rates of grain feeding—zero, quarter, and half grain—offered to the cows on each harvest schedule. The experimental animals were sorted into six groups of six cows each and the cows within a group were assigned to treatments at random. The temperature of soilage held from the morning to the afternoon feeding, by periods of 2 wk. each, rose a minimum average of 10.8° F. in early June and a maximum average of 38.2° F. in late July. During the entire experiment the average temperature rise was 17.3° F. from the morning to the afternoon feeding and 31.0° F. from the afternoon until the morning feeding. Average daily dry matter intakes and adjusted daily production of 4% fat-corrected milk indicate that cutting only once was not deleterious. Either rate of grain feeding resulted in significantly higher milk production than no grain. Grain at the rate of 0.2lb. per pound of milk above 20 for Holsteins and 0.25 for each pound of milk above 12 for Jerseys (half rate) seems justified.

Lactation Studies. II. Comparison of Techniques to Measure True Milk and Fat Secretion Rates in Dairy Cattle as Applied to Between-Milking Intervals of Various Lengths of Time ,

Summary Twenty cows were used over a 2-yr. period to compare three techniques of measuring rates of milk and fat secretion. Apparent secretion rates (pounds of milk obtained at normal milking times divided by hours in the between-milking intervals to get pounds per hour) were compared to true secretion rates which where determined by two methods, using oxytocin to obtain complementary milk. Oxytocin was used at four consecutive milkings and at four milkings spaced so as to effect recovery between injections. Three milkings schedules were employed, i.e., (10–14), (11–13), and (12-12). Actual secretion rates were computed and these also were converted to relative rates which expressed the relation between day-time and night-time secretion rates. The true secretion rate measurement which was most consistent was the one in which oxytocin was injected at consecutive milkings. It was necessary to consider differences in complementary milk left in the udder after milkings, even when a 12-12 hr. milking schedule was used, in order to measure true secretion rates. True secretion rates of milk and fat on a within-interval basis were increased significantly by decreasing the between-milking interval by 4 hr. relative to the other interval in the same day (14 and 30% higher for milk and fat, respectively). The milk and fat secretion rates were higher by 5 and 10%, respectively, during the 11-hr. intervals, as compared to the 13-hr. intervals, but were not statistically different. It was not possible to ascertain whether the 24-hr. rate was affected by changes in milking schedule, because schedule and lactation trend effects were confounded.

Effect of Enzyme Supplementation of Milk Replacers on the Growth of Calves1,2

Summary Two experiments were carried out to determine the effect of supplementing milk replacers with enzymes. In the first experiment, a vegetable milk replacer was predigested with malt diastase, papain, and a combination of these enzymes. Fifty-five pounds of milk were fed through the 20th day and 30.5lb. of the treated milk replacer were fed through the 40th day. The experiment was terminated at 60 days. There was no significant improvement in growth or feed consumption with any of the treatments at either 40 or 60 days. Decreased growth and appetite, and increased mortality, although not significant, tended to indicate that the use of papain produced deleterious effects in this experiment. In the second experiment, soybean flour–corn, soybean flour–cerelose, and skimmilk-cerelose milk replacers were supplemented with pepsin but were not predigested. All other aspects of this experiment were similar to the first one. Pepsin produced no improvement in growth with any of the replacers. The skimmilk–cerelose replacer produced significantly greater growth than the other replacers at 40, and the soybean flour–cerelose replacer at 60, days. The soybean flour-cerelose replacer significantly decreased the rate of starter consumption through 40 days.

Effect of Previous Ration on Lactation Response to Substituting Corn for Alfalfa According to Net Energy and Total Digestible Nutrient Systems of Estimation

Summary The lactation response to the substitution of 10lb. alfalfa with 7.0 or 5.7lb. corn based, respectively, on the TDN or NE system was studied, in a double-reversal trial, with 24 cows previously fed equivalent therms NE per unit of live weight from either of two basal rations: 100% alfalfa or 80% alfalfa plus 20% corn. Basing the substitution on the TDN system resulted in greater energy intake than the NE system, 0.99 therm and 0.94lb. TDN. Across both basal rations, the TDN basis of substitution resulted in significant increases in average daily milk production, 0.89lb. milk, 0.025lb. fat, and 0.73lb. FCM, and a 0.10 decrease in the fat percentage, over the NE basis. Assessing the advantage of the TDN basis of substitution for each basal ration fed, the cows previously fed the 80% alfalfa plus 20% corn basal ration failed to respond; whereas, those previously fed the 100% alfalfa basal showed the following significant advantages: milk 1.56lb., fat 0.051lb., and FCM 1.39lb. When 10lb. alfalfa were replaced with equivalent NE from corn, milk production increased 1.55lb. and FCM 0.94lb. for the 100% alfalfa basal. No significant changes for the 80% alfalfa plus 20% corn basal were observed and across both basal rations, a slight increase in pounds of milk.

Effects of Vacuum Level and Milking Duration on Milk Production, Milking Time and Rate of Milk Flow in Mastitis-Free First Calf Heifers

Summary Twelve mastitis-free first calf heifers, nine Holsteins and three Jerseys, after a 4-week standardizing period, were randomly assigned to be milked for 40 weeks at a vacuum level of 10, 13, or 17 in. of mercury. Halves of udders were assigned to a milking duration of either normal or twice normal. Yields of total pounds of milk, PCM, and fat, and per cent of fat were unaffected by milking at different vacuum levels. Cows milked at higher vacuums tended to be more persistent. Milking time decreased significantly with increasing vacuum and rate of flow increased, but the amount of strippings expressed as percentage of total yield tended to be less for the 13 in. group. Stripping time and time to reach peak flow did not seem to be directly related to vacuum levels. Halves milked for the twice normal time gave slightly greater amounts of milk and significantly more PCM, whereas pounds of fat and per cent of fat were unaffected. The halves milked for the longer duration had significantly slower rates of decrease for total milk yield, pounds of fat, and FCM. Although no differences in the milking time, time to reach peak flow, and amount of strippings were observed, significantly less time was spent stripping, and faster average rates of flow were noted, for the halves milked for twice the normal time.

Relation of Corn and Alfalfa Silage to the Quality of Cheese and its Carotene and Vitamin A Content

Summary Eight lots of cheese made from three types of silage milk were studied with respect to quality and vitamin A potency. Cheese made from milk produced on an alfalfa silage ration equalled or excelled in quality and vitamin A potency, cheese made from milk produced on a corn silage ration. A method for the determination of carotene and vitamin A in the cheese was devised. The distribution of vitamin A potency in cheese-making was shown to be as follows: 85 per cent was retained in the cheese, 7 per cent was found in the whey and 8 per cent remained unaccounted for. A pound of milk, which contained on the average 83 μg. of carotene and 109 μg. of vitamin A, gave cheese containing 69 μg. of carotene and 93 μg. of vitamin A. The whey accounted for 6.5 μg. of carotene and 7.5 μg. of vitamin A; thus leaving about 7.5 μg. of carotene and 8.5 μg. of vitamin A unaccounted for. The vitamin A potency of cheese during curing and storage was practically unchanged over almost a year.

Fat Degradation in Cheddar Cheese Made from Pasteurized Milk, Without and With Added Lipase1,2

Summary The fat acidities of cheddar cheese made from pasteurized milk without added lipase were very similar when the cheese were 3 days old. Increases occurred throughout the ripening period. The increases were not uniform with the different lots of cheese and could not be correlated with the pH of the cheese, the acidity of the whey at milling, or the moisture or fat content of the cheese. The fat acidities of cheese made with rennet extract and with rennet powder increased at approximately the same rate. Purified butterfat, obtained from pasteurized sweet cream and held at the cheese ripening temperature (50° F.), did not increase significantly in acidity. Addition of a small amount of rennet paste (13 to 40 grams per 1,000 pounds milk) resulted in an increase in fat acidity of the cheese. Some of the cheese showed varying degrees of rancidity early in the ripening, but this rancidity disappeared or nearly disappeared before the cheese were 6 months old. The cheese (made with rennet paste) that were not rancid were superior in flavor to the control cheese. The use of a small amount of rennet paste tended to mask the sour, acid flavor frequently encountered in the control cheese. Addition of a larger amount of rennet paste (50 to 225 grams per 1,000 pounds of milk) resulted in a significant increase in fat acidity of the cheese. All of the cheese showed rancidity at some time during the ripening and certain lots were rancid when the cheese were 6 months old. The addition of mulberry juice to pasteurized milk did not improve the flavor of the resulting cheese. Small amounts had little effect on the flavor while larger amounts resulted in rancid and unclean flavors. The use of a certain amount of aged cheese showing definite fat hydrolysis was beneficial from the standpoint of flavor of process cheese. Process cheese containing some aged cheese made with addition of rennet paste had more flavor than process cheese made with an equivalent amount of aged control cheese.