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Effects of zinc, copper, and manganese supplementation of high-concentrate ration on digestibility, growth, and tissue content of Holstein calves.

The effects of supplemental zinc, copper, and manganese alone or in combination in a high-concentrate ration were studied in 16 Holstein bull calves during a 10-wk feeding trial. Metabolism was studied after the feeding trial. Apparent digestibility of dry matter, nitrogen, and gross energy, and nitrogen retention and urinary excretion of zinc, copper, and manganese were determined. The calves were slaughtered after the experiment, and liver, heart, and kidney were taken for analyses of trace minerals. Supplementation of the basal ration with the trace minerals did not affect body weight gains, which averaged 1.42 kg daily. The addition of trace minerals did not affect apparent digestibility co-efficients. A zinc-manganese interaction in digestion of nitrogen and gross energy was significant. Higher dietary manganese caused increased zinc concentrations in the liver, kidney, and heart. The copper concentration of liver was decreased by dietary zinc and increased by dietary copper and manganese. Supplemental manganese increased its net retention. There was no evidence of deficiency of any trace minerals in the unsupplemented treatments.

Animal Feed↗

Effects of zinc, copper, and manganese supplementation of high-concentrate ration on gastrointestinal absorption of copper and manganese in Holstein calves.

Sixteen Holstein bull calves were fed a high-concentrate ratio supplemented with zinc, copper, and manganese, alone or in combination, for 10 wk. After 6 days of preliminary feeding of chromic oxide, fecal grab-samples were collected for 6 days. Calves were slaughtered, and samples of the contents of the reticulo-rumen, omasum, abomasum, small intestine, cecum, and large intestine were analyzed for chromic oxide, copper, and manganese. Absorption along the gastrointestinal tract, measured by comparison of one segment with the previous segment, indicated net secretion of copper in the abomasum but net absorption from the rest of the tract. The exception was that net secretion into the reticulo-rumen was associated with low dietary copper. Net secretion of manganese was mainly in the small intestine and cecum in all treatments. A higher proportion of copper apparently was absorbed when this mineral was supplemented in the ration. However, absorption of manganese was decreased slightly when manganese was supplemented in the ration. Reabsorption of manganese in the large intestine was probably greater than that of copper.

Absorption↗

Physiological responses of lactating cows to gossypol from cottonseed meal rations.

We evaluated the potential for gossypol intoxication and resulting effects of feeding large amounts of cottonseed meal to dairy cows in early lactation. Twenty-four Holstein cows were grouped by age, prior production, and days postpartum and randomly assigned to one of three diets. After 14-day standardization cows individually were fed a blended corn-corn silage ration supplemented with screw-pressed cottonseed meal, direct solvent extracted cottonseed meal, or soybean meal during a 14-wk comparison. Packed cell volume, copper in plasma, activities of transaminases, and gross composition of milk were not affected by ration. Hemoglobin was depressed, and total protein of plasma was elevated by the 9th wk in cows fed the solvent meal. Erythrocyte fragility was detected in those cows by the 7th wk and appeared later in cows fed the pressed meal. Gossypol was identified and quantitated in plasma and liver but was not detected in erythrocytes or milk from cows fed cottonseed meal. Elevated ambient temperatures precipitated increased respiration rates in the cows fed solvent meal. Physiological changes and gossypol in tissues of cows suggest that intoxication is possible in mature ruminants consuming cottonseed meal containing high free gossypol.

Animal Feed↗

Influence of ration form and nitrogen availability on ruminal fermentation patterns and plasma of growing bull calves.

Nine rations containing three forms (ground hay, .2 to 2 cm; chopped hay, 6 to 10 cm; or all concentrate) and three percents (30, 45, and 60%) of rumen degradable nitrogen were fed to 54 Holstein calves (3 X 3 factorial) between 8 and 20 wk of age. Rumen fluid samples were obtained at 8, 11, 14, 17, and 20 wk of age and plasma at 14 and 20 wk of age. Rumen fluid acetate concentration was greatest for ground hay and lowest for concentrate; propionate was greatest for concentrate and lowest for calves fed ground hay. Calves fed concentrate had highest valerate and total volatile fatty acid concentration, whereas lactate concentration and pH were least for concentrate. Ruminal ammonia nitrogen increased with increasing ruminally degradable protein feedstuffs in the ration. Plasma acetate was highest for chopped hay and lowest for concentrate, whereas calves fed concentrate and ground hay were comparable with higher propionate and glucose concentrations than calves fed chopped hay. Plasma urea nitrogen was highest for calves fed 60% ruminally degradable protein.

Animal Feed↗

Effect of varying protein and energy densities in complete rations fed to cows in first lactation.

Sixty-three Holstein cows in first lactation were allotted randomly at 28 days postpartum to receive one of nine rations in a 3 X 3 factorial design. Rations had crude protein 12, 15, or 18% in each of three energy densities from ratios of forage:concentrate of 75:25, 55:45, and 35:65. Corn silage and hay crop silage were combined in a ratio of 2:1 (dry basis) in each case, and diets were offered for ad libitum intake as complete feeds for an 11-wk experimental period plus 2 wk for a digestion trial. In regression analysis as energy density increased, feed intake, milk yield, milk protein, and lactose yields increased linearly, urea nitrogen in blood plasma decreased linearly, and milk fat percent and yield decreased curvilinearly. As dietary protein increased, feed intake, fat-corrected milk, milk fat yield, and plasma urea nitrogen increased linearly, and yields of milk, solids-corrected milk, milk protein, and lactose increased curvilinearly. Actual milk yield adjusted for dry matter intake increased with greater energy density but not with higher protein concentration. Increases of energy and protein each resulted in linear increases of digestibility of dry matter, crude protein, and energy of diets. There were no interactions of energy X protein for these measurements. Cows in first lactation will increase milk production in response to increasing protein over a range of energy densities when feed intake is increased.

Animals↗

Effect of sodium bicarbonate and magnesium oxide in an alfalfa-based total mixed ration fed to early lactating dairy cattle.

Forty-eight lactating Holstein cows were fed a total mixed ration of 57% concentrate and 43% forage (dry basis) for 12 wk postpartum. Treatments consisted of 1) no added buffers, 2) .4% MgO, 3) .8% NaHCO3, and 4) .8% NaHCO3 plus .4% MgO of the total ration DM. Body weight, DM intake, and milk yield and composition were unaffected by treatment. Gross efficiency of milk production was decreased by the addition of NaHCO3 or MgO. Buffer supplementation had no effect on ruminal volatile fatty acid concentration or blood chemistries.

Animal Feed↗

Comparative responses of lactating cows to total mixed rations or computerized individual concentrates feeding.

A trial was conducted in a commercial dairy herd in which the concentrate part of the ration was fed individually to a group of cows through computerized self-feeders. Performance results were compared with those of a group fed TMR of 65 to 67% concentrates. Rationing of individual concentrates was according to parity, milk yield, milk yield potential, BW changes, and bunk feed-stuffs. Mean intake of concentrates per cow was about 1 kg/d lower in the individually supplemented cows. This was partly compensated for by a higher intake of bunk feedstuffs. Overall daily milk yield per cow was similar to those receiving a TMR in first parity cows, higher in second parity cows, and lower in third and greater parity cows. The higher performance of the second parity cows was achieved in all milk yield potential classes, and the lower yield in subsequent lactations was due to lower performance in low and high potential classes. The individually supplemented cows gained less BW than those in the TMR group. Milk yield per unit of BW was better than milk yield as a variable to refine individual cow supplementation strategy for allocation of concentrates. Results also suggest that the same criteria used for supplementation of concentrates can be beneficial to cows' assignments and movements among different TMR groups. Computerized dispensing of concentrates, when applied properly, can economize on consumption of concentrates when grouping and feeding different TMR are impossible.

Animal Feed↗

Quantity and economic importance of nine selected by-products used in California dairy rations.

Food processing representatives, brokers, nutritionists, livestock producers, and trade associations were surveyed to quantify 9 by-products used for feeding livestock during 1992 in California. The commodities were almond hulls, dried beet pulp, wet brewers grains, wet citrus pulp, pressed citrus pulp, wet corn gluten feed, corn gluten meal, whole cottonseed, and rice bran. The 9 by-products contributed over 2.5 million tonnes and about 27% of the total feed concentrate moved within California during 1992. Market value of these 9 by-products was almost .25 billion dollars. Whole cottonseed accounted for about 31% of the total tonnage of these 9 by-products and provided about 66% of the total CP and 53% of the total NEL of these 9 by-products. The by-products were more valuable as energy sources than CP sources compared with NEL from corn and CP from soybean meal, respectively. Calculations of milk production, based on the CP content or NEL content of the by-products, showed that these 9 by-products could have contributed sufficient CP or NEL for over 31% of the milk produced in California during 1992. Ration formulations demonstrated that the economic value of by-products changed with feedstuffs available and, in general, would be used in rations over a range of market prices.

Animal Feed↗

The effects of changing ration ingredients on acid-base status, renal function, and macromineral metabolism.

Ten Holstein and 2 Ayrshire cows were used in a switchback design to compare diets based on alfalfa haylage and corn silage. Both diets had a similar cation-anion difference and contained 1% NaHCO3. Dietary treatment did not affect DMI, DM digestibility, milk production, or milk composition. Intake, absorption, and urinary excretion of N were significantly increased by the ration based on haylage, but the overall balance remained unaffected. Cows consuming haylage absorbed and excreted significantly more water than did cows consuming corn silage and consequently had significantly larger urine volumes. Blood volume was increased by the ration based on haylage. Intakes of Mg, K, Cl, and S differed between diets, but only K balance was increased by the diet based on haylage. The fractional excretion of K, Cl, and S in urine was increased by the diet based on haylage, demonstrating that the kidneys responded to the increased intakes by diminishing the reabsorption or by increasing the secretion of these minerals. Acid-base parameters for blood, urine, and milk were unaffected by dietary treatment. A diet based on alfalfa haylage, compared with a diet based on corn silage with similar cation-anion difference, resulted in different water and mineral metabolism but did not affect the acid-base status of cows in early lactation.

Absorption↗

The effect of preservatives based on propionic acid on the fermentation and aerobic stability of corn silage and a total mixed ration.

For 3 successive yr, whole-plant corn was ensiled in laboratory silos with low percentages of silage preservatives, the primary active ingredient of which was propionic acid. Preservatives were added to forage just prior to ensiling at rates of 0.1 to 0.2% of the fresh forage weight. In all 3 yr, treatments had minor effects on fermentation end products, except that the concentration of propionic acid was greater because of its addition. The mean low and high percentages of preservatives increased aerobic stability of the treated silages by 19 and 57 h, respectively, in Experiment 1 and by 17 and 38 h, respectively, in Experiment 2. In Experiment 3, aerobic stability was improved by > 90 h by preservatives (0.2% addition). In a lactation study, a total mixed ration (46% dry matter) was mixed without or with (0.2 or 0.3%) a stabilizer that was designed to prevent spoilage in the feed bunk. The high dose resulted in orts with a lower pH and temperature after 24 h in the feed bunk. However, dry matter intake and milk production were unaffected by treatments. Chemical preservatives based on propionic acid added at low rates did not affect fermentation but were effective in the reduction of heating in corn silage and in a total mixed ration.

Aerobiosis↗

Performance and nutrient intake of high producing Holstein cows consuming pasture or a total mixed ration.

We compared the intakes of nutrients by high producing Holstein cows consuming pasture or a full nutrient positive control ration (total mixed ration; TMR) and identified nutrients that limited the milk production of cows consuming the high quality pasture. Cows (n = 8) were adapted to an all pasture diet by incrementally reducing the amount of TMR fed over a 4-wk period. A control group of cows (n = 8) remained in confinement and was fed a TMR. The performance of grazing cows differed significantly from that of cows fed the TMR in dry matter (DM) intake (19.0 vs. 23.4 kg/d of DM), milk production (29.6 vs. 44.1 kg/d), milk protein content (2.61% vs. 2.80%), live weight (562 vs. 597 kg), and body condition score (2.0 vs. 2.5). The high quality of the pasture permitted cows to consume the same daily intakes of neutral detergent fiber and crude protein (kilograms per day) as cows fed the TMR, but the pasture provided 19% less DM, organic matter, and net energy for lactation. Predictions using National Research Council estimates and the Cornell Net Carbohydrate and Protein System model indicated that the supply of metabolizable energy was first-limiting for the milk production of cows consuming high quality pasture rather than the supply of metabolizable protein or amino acids. Although a daily intake of 19 kg of DM was achieved on spring pasture, the significant mobilization of energy reserves indicated that supplemental energy is required to achieve milk production greater than 30 kg/d from high producing Holstein cows on intensive grazing systems.

3-Hydroxybutyric Acid↗

The use of fiber concentrations for ration formulation.

Dairy cattle require fibrous feedstuffs in the diet. However, defining the fiber requirements requires knowledge of many interacting components within the diet as well as how the feed is allocated and processed. To meet the demands of high producing dairy cows for energy, diets consist of large quantities of concentrates and high quality forages containing relatively low amounts of fiber. However, to maintain normal rumen function and milk fat percentage, a large portion of the fiber needs to come from forage. Current National Research Council recommendations are a minimum of 25 to 28% dietary neutral detergent fiber, 75% of which is supplied from forage. Chemical measures of fiber alone are not adequate for ration balancing; fiber varies in its effectiveness at stimulating chewing. This variation is greater when feeds contain high amounts of by-products in place of forages. The effectiveness in stimulation of chewing of fiber is variable as the particle size and retention times of indigestible and digestible fiber vary. Currently, little information exists about the fiber requirements of the cow from immediately postcalving until peak lactation. Early lactation cows are clearly more limited by physical fill than are cows in mid and late lactation. Rations based on nonforage fiber sources (> 45% neutral detergent fiber on a dry matter basis) are being evaluated for early lactation cows. Information is needed to determine the variation in the amount of fermentation acids produced, chewing activity, and amount of saliva secreted as these all contribute to the physical effectiveness of fiber.

Animal Feed↗

Amino acid supplementation of low protein turkey starting rations.

Turkey poults fed rations containing 22.1% protein had a much slower rate of growth when compared with poults receiving a ration containing 29.8% protein. Methionine supplementation had no effect on body weight and mortality to 18 days of age. Supplementation of the 22.1% protein diet with lysine (0.2%) significantly improved growth rate over the unsupplemented 22.1% protein diet. The addition of methionine to the 22.1% protein diet supplemented with lysine (0.2%) produced slight additional response in body weight; however the drop in mortality was much more dramatic as increments of methionine were added to the 22.1% protein diet supplemented with lysine (0.2%).

Amino Acids↗

Amino acid supplementation of turkey breeder rations.

Beltsville Small White turkey hens (60) were randomized into four groups of 15 hens each, weighed and placed in individual laying cages. Immediately after lighting to initiate production, they were placed on a practical type turkey breeder diet calculated to contain 18.26% protein, 2893 Cal. M.E./kg., 3.13% Ca, 0.80% available P, 1.04% arginine, 0.86% lysine, 0.50% methionine & cystine and 0.24% tryptophane. Amino acids were added to this diet as follows: (1) none; (2) 0.1% lysine; (3) 0.05% methionine and (4) 0.1% lysine & 0.05% methionine. Lysine (0.1%) had no effect on reproductive performance when added to the basal ration or to the ration containing additional methionine. Methionine addition (0.05%) improved production significantly (P less than or equal to .005), improved feed efficiency, and increased egg size.

Amino Acids↗

Incidence of degenerative myopathy among turkeys fed corn or wheat based rations.

Turkeys were fed either corn based or wheat based rations and necropsied between 28 and 118 weeks of age. Practically all birds affected with degenerative myopathy were detected among those killed between 77 and 85 weeks of age. The incidence of the disease was 0% among 125 males and 7.9% among 139 females. No significant difference in incidence was observed between birds fed corn based and birds fed wheat based rations.

Animal Feed↗

Feed and water consumption and performance of male and female broilers fed salinomycin and maduramicin followed by a withdrawal ration.

A 3 x 2 factorial floor pen experiment was conducted to determine the effects of feeding salinomycin (60 ppm) or maduramicin (5 ppm) for 49 days followed by a 3-day withdrawal ration upon both male and female broiler chickens in a coccidia-free environment. Body weights, feed intake, and water consumption were recorded at 28, 49, and 52 days of age. Feed efficiency and overall mortalities were also measured. Inclusion of either ionophore into the ration had no effect on final body weight, but improved feed conversion (P less than .05). Birds fed maduramicin drank more than the nonmedicated birds (P less than .05), which in turn, drank more than the birds fed salinomycin (P less than .05).

Animals↗

Pain and analgesia: the outlook for more rational treatment.

Recent advances have been made in research on the physiology of pain, especially that focusing on the primary afferent nociceptor and endogenous analgesia systems. These advances have shed new light on the mechanisms of action of some long-used methods of managing pain, have led to the development of several methods, and have suggested new lines of investigation that may lead to more rational treatment of pain. The earlier that we can intervene in the pain-transmission pathways, the more likely we are to produce adequate and lasting control of pain. The peripheral nervous system is an important target for this therapeutic approach. The elucidation of the central neural pathways, which contain endogenous opioids and mediate the analgesia elicited by opiates, has raised the possibility of more rational use of this class of analgesics. The rationale for the use of current therapies needs to be reexamined in light of these new findings, and both current and new methods need to be tested in controlled trials.

Afferent Pathways↗

Successful implementation of a guideline program for the rational use of lipid-lowering drugs.

Following the National Cholesterol Educational Program's (NCEP) 1988 screening and treatment recommendations, an educational and behavior-change program at Group Health Cooperative of Puget Sound (GHC) was developed to guide the use of lipid-lowering drugs within the larger context of cardiac risk reduction. The program has been successful in advancing a rational program to enhance care and manage costs of the use of lipid-lowering agents at GHC. Cost savings have been significant over the past two years. The educational design of the program includes training and ongoing education of a core group of "lipid gurus," who educate colleagues in area medical centers in a rational approach to hyperlipidemia. Patient education and patient participation in decision-making was emphasized. Program evaluation has demonstrated that physicians and patients are satisfied with the program, and inappropriate drug expenditures have been prevented. Key elements of the program include a critical review of outcome studies in the medical literature, use of information systems, algorithms and written materials organized into a well-designed, ongoing educational program, and development of a core group of physicians and pharmacists to administer the program at the clinic level.

Algorithms↗