Fat Depression Research Articles

Fat depression in milk obtained from Simmental and native (Yerli Kara) cows in first month of postpartum period

Fat depression in milk obtained from Simmental and native (Yerli Kara) cows in first month of postpartum period

The Relationship between Body Fat Percentage and Depression in Female College Dancers according to the Subspecialty

The Relationship between Body Fat Percentage and Depression in Female College Dancers according to the Subspecialty

Preservation and Storage Mechanisms for Raw Milk Samples for Use in Milk-Recording Schemes

This study, carried out by the Quebec Dairy Herd Analysis Service, compares (during summer conditions in Quebec) the performance of three types of preservatives for raw milk under four different systems of sample storage: no refrigeration, refrigeration at the laboratory only, refrigeration during transport and at the lab, and complete refrigeration from sampling at the farm to analysis. The objective was to determine the best preservative and storage conditions for protecting milk components during transportation and storage of raw milk samples collected at the farm and sent to a central testing lab for analysis. Milk samples were analyzed at day 3 and at day 7 after sampling to observe the effect of aging. A total of 12,480 samples were collected during the trial. The components studied were percentage of fat and protein and somatic cell count (SCC). In general, samples preserved with bronopol (2-bromo-2-nitropropane-1,3-diol and 2-bromo-2-nitropropanol) in liquid or in microtab tended to give higher readings for fat and protein contents than samples preserved with potassium dichromate. Significantly lower fat values were observed in 7-day-old samples compared to 3-day-old samples. Fat depression was more accentuated in nonrefrigerated samples. Under current methods of handling raw milk samples, refrigeration during the whole process of sampling, transportation, and until analysis, seems an ideal to attain to avoid significant reductions of fat values.

Reduced feed intake in cows after peroral calcium

The influence on daily feed intake of treatment with 3 different commercial CaCl2-containing products and pure water was measured. The treatments were 4 perorally administered doses of (1) 1 litre pure water, (2) Ca-oil containing 200 g CaCl2 emulgated in soyabean oil, (3) Ca-capsule containing 126 g CaCl2 and 45 g CaS04, (4) Ca-gel containing 200 g CaCl2 in an ethylcellulose-gel. The treatments gave a reduction in DM intake of 4.7, 12.2, 11.5 and 16.7% respectively on the day of treatment. The energy intake was reduced about the same except for the Ca-oil treatment where the energy intake was not reduced due to the oil. It was concluded that the mechanisms causing the reduction might be handling of the cows, increase of the osmotic pressure, fat depression in the rumen, and etching effect of the rumen wall.

DAY-TO-DAY VARIATIONS IN FAT PERCENT OF COW'S MILK

Large day-to-day variations in milk fat, particularly for the morning milkings, were observed in 36 Holstein cows. Changes in percent fat were gradual and produced wavelike patterns in a number of instances. Supplemental feeding of long hay had no effect on acetate/propionate ratio in rumen fluid, daily milk yield or weighted milk fat percentage. Key words: Dairy cows, milk, fat depression, hay

Factors Affecting Differences in Milk Fat Test Obtained by Babcock, Rose-Gottlieb, and Infrared Methods and in Protein Test from Infrared Milk Analysis

In a collaborative study between personnel of the Canadian dairy cattle Record of Performance Services, university laboratory, and central milk testing laboratory of Quebec Dairy Herd Analysis Service, differences in fat tests by Babcock, Rose-Gottlieb, and infrared analyses (Milko-Scan) were studied in individual milk samples from Ayrshire, Holstein, and Jersey herds for 1 yr. On-farm Babcock for fat gave results that were lower by .075, .058, and .016% than laboratory Babcock tests for Ayrshire, Holstein, and Jersey milks. Fat tests by Rose-Gottlieb and Milko-Scan on day of sampling were intermediate between the on-farm and laboratory Babcocks for Ayrshire and Holstein. For Jersey milk, using Rose-Gottlieb as reference method, fat would be overestimated by .021, .037, and .082% when compared with on-farm Babcock, laboratory Babcock, and Milko-Scan results. Lower fat tests were obtained by infrared for 3-d-old samples transported under varying ambient temperature conditions; however, these were not due to error of the instrumental method per se but rather to conditions of milk samples which may have caused the milk to undergo lipolysis. Magnitude of the d 3 fat depression, which varied from nonsignificance to .21%, was accompanied by an increase in protein reading and was also dependent on breed of cow, stage of lactation, and month of the year.

The Influence of Feeding Frequency on Ruminal Parameters and Production Response in Dairy Cattle

The effect of feeding frequency on ruminal parameters and milk production in dairy cattle was reviewed. Increasing feeding frequency generally resulted in a less variable diurnal profile in ruminal pH. Feeding a TMR more frequently did not result in reduced variation of diurnal pH pattern. Forage to concentrate ratio influenced the volatile fatty acid concentration associated with increased feeding frequency. Generally diets containing higher proportions of concentrate (►60% of DM) showed a higher ruminal acetate to propionate ratio with increased feeding frequency. Parameters such as water intake, microbial activity, ruminal digestion and dilution rates were either not affected or positively influenced by increased feeding frequency. Possible modes of action to increase milk yield may be through enhanced efficiency of microbial synthesis and yield and/or increased escape of potentially degradable protein through increased ruminal dilution rate, and/or increased energy intake. A summary of 9 studies revealed that increasing feeding frequency from 2 to 4, 5 or 6 times daily resulted in a slight increase (1.5%) in milk yield. In eight studies, the average increase in milk fat concentration was 6.8%. The primary effect of increased feeding frequency on fat concentration was associated with diets low or marginal in fiber, high in concentrates, and where milk fat was originally depressed. Increased feeding frequency may be of most potential benefit in early lactation, high-producing cows that are in an energy deficient status, where fat depression is of key importance.

EVALUATION OF STEAM-TREATED WHEAT STRAW AS A ROUGHAGE SOURCE IN DAIRY COW RATIONS

Two experiments were conducted involving a total of 24 Holstein cows to evaluate steam-treated (ST) wheat straw as a roughage source in mixed dairy rations. Diets containing ST straw (exp. 1) at 20 and 30% of the ration dry matter (DM) were consumed in amounts similar to a 30% ground alfalfa hay diet and in greater amounts than a mixed diet with 20% untreated (UT) wheat straw. Cows receiving the diet containing 30% alfalfa hay produced more (P < 0.05) milk per day than the group fed a mixed diet with 20% UT straw, but similar amounts to those cows fed the two ST straw diets. Milk fat (%) was not different (P > 0.05) among the four treatments. Cows fed the diet containing 30% ST straw had a lower (P < 0.05) ruminal fluid acetate: propionate ratio compared with a 20% UT straw mixed diet. In the second experiment, cows receiving a diet containing 30% ST straw plus 30% rolled barley in place of 60% corn silage consumed less (P < 0.05) total DM and produced less 4% fat-corrected milk per day with a depressed (P < 0.05) fat test. Propionic acid level in rumen fluid was elevated (P < 0.05), which lowered the acetate: propionate ratio in ruminal fluid of cows receiving the diet containing 30% ST straw compared to cows receiving the corn silage diet. Data from these studies suggest that up to 20% steam-treated wheat straw (DM basis) could be included in total mixed dairy rations without any appreciable influence on animal performance. However, at higher levels ST wheat straw is a less "effective" fiber or roughage source in dairy rations. Key words: steam-treated, wheat straw, Holstein cows, fat depression, feed consumption, effective fiber

Glucose Metabolism in Cows Fed Low— and High—Roughage Diets

Six lactating first-calf Holstein cows were used to test the effect of dietary roughage on glucose metabolism. Cows were fed either a low-roughage or high-roughage diet at isocaloric digestible energy intakes in a double changeover design experiment. Mean values (± standard deviation) for milk yield (kg/day), fat (%), lactose (%), and protein (%) for cows fed low-roughage were 19.0±4.4, 3.11±.78, 5.19±.27, 3.44±.48; values for cows fed high-roughage were 17.5±5.1, 3.99±.58, 4.94±.25, and 2.78±.33. One hour post-feeding on the 20th day of each period 2mCi of tritiated glucose were administered to each cow by single injection to measure glucose kinetics. Mean values (± standard deviation) for plasma concentration (mg/100ml) pool size (mg/kg), half-time (min), and utilization rate (mg/kg.75 per min) of glucose, and plasma insulin concentration (μU/ml) for cows fed low-roughage were 63.1±3.9, 17.9±3.4, 30.4±5.2, 8.55±2.44, and 22.0±3.9; for cows fed high-roughage values were 54.9±2.2, 114.5±17.2, 40.0±2.2, 4.06±.38, and 16.1±2.4. A glucose load was administered intravenously to each cow on the last day of each period. Glucose half-times and mean plasma insulin following the clearance test were not affected by diet. Compared to high-roughage, low-roughage diets greatly affect metabolism in lactating cows when isocaloric intakes of each are fed. Fat depression, however, may or may not occur simultaneously.

ACID-TREATED HIGH MOISTURE BARLEY FOR DAIRY COWS

Twelve dairy cows in early lactation were assigned to four dairy concentrates (dry barley, dry barley treated with propionic and acetic acids, high moisture barley treated with propionic and acetic acids and high moisture barley ensiled) in a changeover design. All cows received whole plant barley silage at about 40% of the total dry matter (DM) intake. The dairy concentrates were mixed with the silage at the time of feeding and the mixtures fed ad libitum. Silage intakes appeared to be lower for cows receiving high moisture barley; however, total intake was not different (P > 0.05) among treatments. Milk yield was lower (P < 0.05) for cows receiving the high moisture acid-treated grain compared to those receiving the dry untreated grain. Yield of fat corrected milk (FCM), % butterfat (BF) and % solids not fat (SNF) were not different (P > 0.05) among treatments. In this study there did not appear to be any fat depression with the high moisture grains even though, on average, DM intake by the cows on this diet contained a lower proportion of silage.

Comparative Acceptability and Nutritive Value of Barley, Wheat Mixed Feed, and a Mixed Concentrate Ration in Meal and Pelleted Forms for Lactating Cows1,2

Grain rations consisting of 98% barley, 98% wheat mixed feed, and a control mixture of barley, wheat, peas, and cottonseed meal, fed in meal and pelleted forms, were compared in digestion, lactation, and acceptability trials. Alfalfa hay was fed as the only roughage with each grain mixture at a 55 :45 ratio in the lactation and digestion trials and at a 30:70 ratio in the acceptability trial.Digestibility of dry matter, energy, and total digestible nutrients content of wheat mixed feed rations were lower than barley or control rations. Fed as a meal, wheat mixed feed was consumed at a lower rate than all other grain rations (P<.05) in the acceptability trial.Cows fed pelleted grain rations in the lactation trial produced more milk, protein, solids-not-fat, fat, and fat-corrected milk than those fed meal rations (P<.10). Differences in production of fat-correeted-milk, percentage solids-not-fat, and percentage protein of milk among meal and pelleted rations were small (P>.10). Pelleting the grain rations resulted in the greatest depression of milk fat percentage for cows in the acceptability trial. Fat depression was not as great for cows on the acceptability trial fed wheat mixed feed, a result associated with greater fiber and lower nitrogen-free extract intake. Mean diurnal levels of rumen volatile fatty acids associated with pelleted rations resulted in an increase in molar percentage rumen acetate and a decrease in butyrate, with little change in propionate or valerate compared to meal rations.Cows fed wheat mixed feed as a meal lost weight; those on other treatments gained weight.Wheat mixed feed, fed in pelleted form, was comparable to barley or a mixed grain ration in meal or pelleted forms as the only concentrate for lactating cows.

Effects of the Addition of Bentonite to High-Grain Dairy Rations which Depress Milk Fat Percentage

Twelve lactating Holstein cows were placed on an experiment consisting of three periods: four-week normal control, six-week fat depression, and six-week treatment. In the last period the cows were divided into three groups and allotted to three treatments: I. Fat-depressing ration, II. Fat-depressing ration + 5% bentonite, and III. Fat-depressing ration + 10% bentonite.A highly significant increase in milk fat per cent was noted in both bentonite treatments versus the fat-depressing ration, but there was no significant difference between the two levels of bentonite. The cows in Treatments I, II, and III maintained per cent milk fat at 86, 144, and 144% of the fat-depressing period, and 60, 87, and 87% of the normal control period, respectively. Milk production was significantly higher for Treatment II. A significant increase in the proportion of rumen acetate, along with a decrease in propionate and valerate, was noted in the two bentonite treatments compared to the fat-depressing ration. There was a significant increase in the arteriovenous difference of blood acetate in the two bentonite treatments compared to the fat-depressing ration. Arteriovenous differences for blood glucose and ketones and plasma free fatty acids and triglycerides were not altered significantly.

Milk Fat Synthesis on Restricted-Roughage Rations Containing Whey, Sodium Bicarbonate, and Magnesium Oxide1,2

A study was conducted to elucidate the mechanism through which partially delactosed whey and minerals (NaHCO3 plus MgO) increase milk fat synthesis on restricted-roughage rations and to determine the minimum effective level of the whey. Thirty-six Holstein cows were fed concentrate ad libitum and 2.3kg hay/day for eight weeks. Concentrates contained varying levels of whey (0, 3, 7, and 14%), or minerals (2.5% NaHCO3 and 1% MgO), or both whey (14%) and minerals. Fat depression was least on the mineral rations, but concentrate intake and milk yields were also lowest. As whey in concentrate increased, milk fat also increased, with 14% whey almost as effective as minerals. Compared to controls, rumen pH was increased by minerals but not by whey. Both minerals and whey decreased rumen propionate and increased acetate; whereas, butyrate was increased only at 14% whey. Increased mammary uptake of fatty acids from heparin-precipitable lipoprotein was directly proportional to arterial concentrations and accounted for almost all of the increased milk fat synthesis on the mineral rations, but for about one-half the increase on whey. A larger uptake of β-hydroxybutyric acid was shown for the 14% whey than for other rations and was related to higher concentrations of the shorter chain fatty acids (C6 to C14) in milk. Concentrations of stearate and oleate in milk were increased by minerals and by whey; whereas, linoleate was decreased by additives. Stimulation of milk fat synthesis by whey and minerals mediated through increased mammary uptake of fatty acids from serum lipoprotein was not a metabolic reversion to conditions found on a normal ration sufficient in forage.