Chemical, physical, and environmental properties of pelleted newspaper compared to wheat straw and wood shavings as bedding for horses.

Two experiments were conducted comparing pelleted recycled newspaper (PN) to wheat straw (S) and kiln-dried pine wood shavings (WS) as an animal bedding material. Adult horses housed 20 to 21 h/d in boxstalls served as the animal model for comparisons. In Exp. 1 eight boxstalls, each housing one horse, were each bedded with two types of PN (0.32 and 0.64 x 2.54 cm), S, and WS over four 5-d periods (replicated 4 x 4 Latin square). Initial amounts of bedding materials surpassed most commercial conditions, but stalls were cleaned daily of feces only and additional clean bedding was added as needed to maintain animal cleanliness, thus challenging the bedding properties of each material. In Exp. 2 nine boxstalls were bedded with PN (0.32 x 2.54 cm), S, and WS over three 14-d periods (three 3 x 3 Latin squares) during summer and autumn. Feces and wet spots were removed daily and clean bedding was added to reestablish working volume and simulate commercial conditions. In Exp. 1 and 2 daily additions of clean bedding varied (P < 0.05) with material (S > WS > PN). The higher water-holding capacity of PN and WS contributed to fewer bedding replacements. Usage of each material was greater (P < 0.05) during the autumn; PN had the greatest increase. Type of material and season also influenced bedding environment. Bedding pH increased (P < 0.05) with use and was highest in PN and lowest in S. Higher concentrations of breathable NH3 N were present in stalls bedded with PN and during autumn. Higher pH of used PN and decreased ventilation due to closed doors and windows during autumn were contributing factors. Season, type of bedding, and duration of its use affected (P < 0.05) numbers as well as species of microorganisms present in the breathing zone, nasal cavity, and on the leg of the horse. Clean and used WS contained greater (P < 0.05) quantities of particle fines, but with 5 d of use, particle fines in PN also increased. Quantities of breathable dust during cleaning of stalls varied (P < 0.05) with material and duration of its use; dust peaked at d 7 with PN but continued to decrease with S and to increase with WS through d 14. These data indicate that management of bedding materials varies with type of material and season of year. Use of PN as a bedding material has high potential.

Chemical and physical properties of processed newspaper compared to wheat straw and wood shavings as animal bedding.

Because of continuing concerns about the safety and the suitability of recycled newspaper as an animal bedding material, municipal curbside-collected newspaper was processed into chopped and pelleted forms for comparison studies with wheat straw and kiln-dried pinewood shavings. Measurements included nutrient, heavy metal, dioxin and furan content, particle size distribution, density, combustion potential, and water-holding capacity. Recycled newspaper, straw, and wood shavings tested below or equivalent to National Research Council dietary tolerance levels and US Environmental Protection Agency toxic equivalent levels. Small particle size distribution was shavings > straw > all forms of newspaper. The density of pelleted newspaper was 50-fold greater than that of chopped newspaper and straw and 15-fold greater than shavings. In simulated flash burns, chopped newspaper, straw, and shavings ignited, and flames spread rapidly in newspaper and shavings and lasted the longest in shavings. Pelleted newspaper did not ignite. Chopped and pelleted forms of newspaper and wood shavings had higher water holding capacities (>400%) than did straw (200%). Animal industries can, in confidence, utilize recycled newspaper as an animal bedding material, providing that sources of low toxicity are identified, and suitable processed forms are produced.

Effect of yeast on feed intake and performance of cows fed diets based on corn silage during early lactation.

Thirty-six multiparous Holstein cows were fed a mixture of corn silage and concentrate [1:1; dry matter (DM) basis] and long hay (0.9 kg/d) through wk 18 of lactation. Beginning at 30 d prepartum through wk 4 of lactation, the total mixed rations of 18 of these cows were top-dressed daily with 10 g of Biomate Yeast Plus (Chr. Hansen's, Inc., Milwaukee, WI). The other 18 cows served as controls. At wk 5, both control and treated cows were divided into three groups and fed 0, 10, or 20 g/d of yeast. Yeast supplementation during early lactation significantly improved DM intake, milk yield, and the digestibility of crude protein and acid detergent fiber. Least squares means for DM intake, fat-corrected milk yield, crude protein digestibility, and acid detergent fiber digestibility for cows fed 0, 10, 20 g/d of yeast during wk 5 to 18 of lactation were 23.8, 24.7, and 25.0 kg/d; 37.7, 40.7, and 41.4 kg/d; 78.5, 80.8, and 79.5%; and 54.4, 60.2, and 56.8%, respectively. Although numerical responses in DM intake and milk yield were greater for cows fed 20 g/d of yeast than for cows fed 10 g/d of yeast, the response was not significant.

Cortisol increases in plasma of Holstein heifer calves from handling and method of electrical dehorning.

Changes in cortisol in plasma were used to assess stress when calves were restrained and then dehorned. Thirteen Holstein heifer calves between 3 and 4 wk of age were used over 4 d; each calf served as its own control. On d 1, 2, and 4, blood was sampled initially while calves were in a pen, 5 min after being placed in a restraint chute, and then at 5, 15, 30, and 45 min and 1, 2, 3, 4, 8, and 12 h after simulated or actual dehorning. On d 1, dehorning was simulated. On d 2 and 4, one horn bud of each calf was cauterized, respectively; sequence of horns (right, left) and dehorning instruments (conventional electrical, Buddex) were alternated for all calves. Day or previous dehorning procedures had no effect on initial concentrations of cortisol in plasma. However, after calves were placed in a chute, cortisol in plasma increased with each entrance. Cortisol in plasma peaked at 5 min posthandling (d 1, 11.3 ng/ml) or 15 min postdehorning (electrical, 21.9 ng/ml; Buddex, 20.7 ng/ml). These data suggest that both dehorning procedures resulted in similar rates of synthesis and secretion of cortisol.

Composition, preservation, and use of sea clam viscera as a protein supplement for growing pigs.

Use of surf clam viscera as an animal feed was assessed by measuring nutrient content, susceptibility to spoilage, preservation with organic acid, and replacement value for soybean meal when fed to growing pigs. Viscera exiting the processing plant averaged 88% moisture and 71% CP in DM. Amino acid contents (51% in DM) and profiles were similar to those of soybean meal. Storage and feeding quality of wet viscera could be maintained up to 3 wk by adding formic or propionic acid (3.5%, wt/wt). Pigs readily ate corn-based diets containing wet viscera preserved with propionic acid. Growth rate was similar for pigs from 18 kg to market weight (92 kg) when soybean meal and(or) clam viscera were fed as protein supplements. However, cooked loin roasts from pigs fed one-half or all supplemental protein from viscera (5 or 10% viscera in diet DM) had distinctive fishy aromas. To produce acceptable pork, future studies must identify lower dietary levels or withdrawal periods for viscera.

Yeast culture to improve intake, nutrient digestibility, and performance by dairy cattle during early lactation.

Twenty-four primiparous Holstein cows were fed corn silage:grain (1:1, DM basis) and hay (.9 kg/d) beginning 30 d prepartum and through wk 18 of lactation. Ten grams of Biomate Yeast Plus (5 X 10(9) cfu of Saccharomyces cerevisiae/g) were top-dressed on the a.m. allotment of corn silage:grain fed to 12 cows. Corn silage:grain was restricted during prepartum and thereafter fed for ad libitum intake. Cows fed supplemental yeast peaked earlier and had a higher milk yield compared with control cows (wk 7, 29.5 kg/d vs. wk 11, 28.7 kg/d). Digestibilities of protein and cellulose were improved in cows fed supplemental yeast, contributing to a greater DMI during the first 6 wk of lactation and a higher average milk yield through wk 18 of lactation compared with control cows (27.2 vs. 26.0 kg/d).

Effects of handling, administration of a local anesthetic, and electrical dehorning on plasma cortisol in Holstein calves.

Effects of handling, administration of a local anesthetic, and electrical dehorning on plasma cortisol were measured in Holstein heifer calves. Jugular blood was sampled from 24 calves (age, 7 to 16 wk) within 1 to 2 min after entering their pen (baseline, 0800 h). All calves were then haltered, placed in a restraint chute, an unheated electrical dehorner applied to each horn stump, and a second jugular blood sample obtained 30 min later (handling). Calves were then divided into control and test groups (12 calves). For the next 2 consecutive d the sequence of sampling blood and handling were the same except that 1) for control calves a heated dehorner was used on d 2 (dehorning), and 2) for test calves the cornual nerve of each horn stump was injected with 5 ml lidocaine prior to applying an unheated dehorner on d 2 (administration of anesthetic) and a heated dehorner on d 3 (combination of anesthetic and dehorning). Handling, injection of an anesthetic, and dehorning were stressful and increased plasma cortisol of calves 5.4, 16.8, and 28.3 ng/ml above baseline, respectively. Dehorning and the combination of injecting lidocaine and dehorning resulted in similar increases in plasma cortisol. Different responses in plasma cortisol in individual calves exposed to similar stimuli suggest that synthesis and release of cortisol can be modified.

Phytate phosphorus intake and disappearance in the gastrointestinal tract of high producing dairy cows.

Thirty Holstein cows were fed diets of 50% grain and 50% corn silage (dry matter basis) through the first 18 wk of lactation. Grain mixes were supplemented with inorganic calcium sources (aragonite, calcite flour, or albacar) to provide .6 or .9% dietary calcium (dry matter basis). Phytate phosphorus intake averaged 38.3 and 42.6 g/d in digestion trials conducted during wk 4 and 10 of lactation, respectively. Even though large quantities of feed and significant amounts of grain were consumed, 98% of dietary phytate phosphorus was hydrolyzed to inorganic phosphorus. Neither calcium source nor calcium quantity affected the hydrolysis of phytate phosphorus.

Calcium sources for milk production in Holstein cows via changes in dry matter intake, mineral utilization, and mineral source buffering potential.

Three supplemental sources of inorganic calcium (calcite flour, aragonite, albacar), each differing in particle size and rate of reactivity, provided .6 or .9% calcium in corn silage:grain (1:1 dry matter) diets of high producing dairy cows. All cows were fed calcite flour at .6% calcium during the first 4 wk of lactation. On d 29 of lactation 5 cows were assigned to each of the six diets. Peak milk yield paralleled dry matter intake and was higher when calcite flour and aragonite provided .9% calcium, intermediate when all sources provided .6% calcium, and lower when albacar provided .9% calcium. However, adaptations to calcium source and to particle sizes of a calcium source (.35 to 1190 mu) were made within 40 d by lactating Holsteins. Starch increased and pH decreased in feces of cows fed albacar. Increasing calcium in the diet provided more buffering capacity in the gastrointestinal tract. True absorption of calcium did not differ from linearity due to source when fecal calcium was regressed on ingested calcium but did vary as a function of diet percentage. Thus, calcium retention was increased when cows were fed .9 vs. .6% calcium. These data suggest that a slow reacting (coarser) inorganic calcium source should be fed at a higher amount to optimize feed intake and milk production.

Effects of stress from electrical dehorning on feed intake, growth, and blood constituents of Holstein heifer calves.

Eighteen Holstein heifer calves were allotted to two groups. Calves in one group were dehorned electrically at 8 wk of age whereas the control group remained horned through 12 wk of age. Feed intake and growth rate did not differ between the two groups. Blood constituents varied with age, nutrition of calf, and dehorning. Dehorning influenced cortisol in blood plasma with high concentrations (25 versus 6 ng/ml) measured for 1 h after dehorning. Electrical dehorning at 8 wk of age presents no long-term stress to calves.

Blood constituents in lactating Holstein cows influenced by hematocrit, sampling site, and diet protein and calcium.

Constituents were measured in jugular vein (days 0, 4, 14, 28, 43, 72, and 151 of lactation) and internal iliac artery and mammary vein (days 28, 72, and 151 of lactation) blood of 24 Holsteins. Six diets of grain:corn silage-urea contained percents of protein and calcium: 12, .6; 12, .9; 15, .6; 15, .9; 15, .6; 15, .9. Grain contained urea (diets 3, 4) or soybean meal (diets 5, 6). All cows were fed diet 3 the first 4 wk of lactation; then four cows were assigned to each of six diets. In jugular blood, calcium and phosphorus were lower on day 0. Hydroxyproline and ketone bodies peaked and magnesium was minimal on day 4. Hematocrit, urea nitrogen, and free fatty acids decreased with lactation. Jugular blood from younger cows had less ketone bodies, free fatty acids, and magnesium and more hematocrit, hydroxyproline, and phosphorus. Sampling site had arterial-venous differences for each constituent, with venous differences for hematocrit, free fatty acids, calcium, phosphorus, and magnesium. Hematocrit decreased with diets 1, 2, 3, 4, or .6% calcium. With a common hematocrit (36%) and change from baseline (day 28), urea nitrogen was less with 12% protein or .6% calcium. Phosphorus and magnesium decreased with 15% protein. More constituents were required from diet and tissues to maintain concentrations in blood as hematocrit decreased, indicating the importance of dietary calcium and protein concentration and quality.

Milk yield by Dorset ewes as affected by sibling status, sex and age of lamb, and measurement.

Milk intake (sucking-test weight) by 55 Dorset lambs and milk production (oxytocin-hand milking) by 41 Dorset ewes were measured at 2-wk intervals during the first 8 wk of lactation. Each method indicated that milk yield by ewes was greater at 2 and 4 wk of lactation than at 6 and 8 wk. Daily milk intake by a set of twins (suckling-test weight) was similar to 24-h milk production of their dam (oxytocin-hand milking) when lambs were 2, 4, 6, and 8 wk of age. At 2, 4, and 6 wk postpartum, milk production by ewes nursing single lambs was 200 to 400 g greater than milk intake by lambs due to a larger residual milk. Stage of lactation had a significant effect on protein and fat content of milk but not on lactose. Sex of offspring had no effect on milk yield or protein, fat, and lactose content of milk. Lactose was one percentage unit greater in milk of ewes nursing single lambs; however, the amount of lactose secreted daily was similar for ewes nursing single or twin lambs. Twenty-four-hour milk production by the ewe as determined by the oxytocin-hand milking method was correlated with lamb growth (.67 to .86), with milk intake, as determined by the suckling-test weight method, the next most important variable. Milk composition contributed little toward modeling lamb growth.

Effect of docking on health, blood cells and metabolites and growth of Dorset lambs.

Docking by knife or elastrator had no sustained effect on growth of lambs 0 to 8 wk postpartum. However, during the 2 wk period postdocking, growth of lambs was limited or depressed, regardless of whether lambs were docked by knife at 14, 28 or 42 d of age. Blood hematocrit and hemoglobin were decreased (P less than .01) 1 d after docking by knife and 14 d after docking by elastrator. Neither method of docking proved superior. Regardless of whether lambs were docked by knife or elastrator, tail tissue was destroyed and became necrotic. Numbers of white blood cells increased (P less than .01) in response to docking. This necessitates that lambs be observed often through 2 wk postdocking and that medical treatment be administered when needed.

Valine, leucine, and isoleucine metabolism by lactating bovine mammary tissue.

Valine, leucine, and isoleucine were extracted by the lactating bovine mammary gland in excess of outputs in milk protein. Carbon-14 uniformly labeled L-valine, L-leucine or L-isoleucine were catabolized when incubated in vitro with lactating bovine mammary tissue slices. The pathways of degradation of these amino acids by mammary tissue appear to be those common to other tissues. These amino acids represent a potential source of energy to the mammary gland as well as a source of carbon and alpha-amino nitrogen for synthesis of nonessential amino acids.

Effect of sampling location, time, and method of concentration of ammonia nitrogen in rumen fluid.

In experiment 1, rumen fluid samples were obtained from dorsal, midpoint, and ventral regions of the rumen of rumenfistulated dairy cows at hourly intervals for 24 h. Dorsal, midpoint, and ventral rumen fluid samples contained 16.1, 14.2, and 12.1 mg/100 ml of ammonia nitrogen. Time after feeding resulted in differences in the concentration of ammonia in rumen fluid with the greatest concentration 30 to 90 min postfeeding. The concentration of ammonia nitrogen was greater for cows fed a high-concentrate diet (14.7% crude protein, 86% concentrate) than for cows receiving a normal diet (15.1% crude protein, 42% concentrate), 15.2 versus 13.1 mg/100 ml. In a second experiment, rumen fluid samples were obtained immediately before feeding and at 1 and 6 h postfeeding by stomach tube and from dorsal, midpoint, ventral, and mixed rumen contents via a rumen cannula. Concentrations of ammonia nitrogen (mg/100 ml) in the respective rumen fluid samples were 14.3, 23.0, 18.3, 17.2, and 19.6. Location of sampling, method of sampling, time of sampling, type of diet, and rumen fluid volume are factors that affect the concentration of ammonia nitrogen in rumen fluid.