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We conducted an experiment to evaluate the effects that a diet containing condensed tannins with and without polyethylene glycol (PEG) has on lamb growth and meat quality. Twenty-three male Comisana lambs were introduced to the three experimental diets between 45 and 50 d of age. Eight were given a diet containing 56% of Ceratonia siliqua (carob) pulp (tannin group), another eight received the same diet with a supplement of 40 g of PEG for each kilogram of diet (PEG group), and the remaining seven lambs were given a conventional maize-based diet (maize group). Voluntary feed intake and live weights were measured until slaughter at 105 d of age, and digestibility measurements were undertaken toward the end of the feeding trial. Carcass yield, meat quality characteristics, and a taste panel evaluation were conducted. The tannin-based diet contained 2.5% condensed tannins (DM basis), and lambs given this diet had lower growth rates and poorer feed efficiencies (P < .01) compared with the other treatment groups. Daily gain was similar between the maize and PEG lambs, although the efficiency of feed conversion was highest in the maize group. The digestibility of DM, N, and fiber was reduced (P < .05) by the condensed tannins. Lambs fed the tannin diet had a lower carcass yield (P < .05) and had less fat (P < .05), and the meat had a higher ultimate pH (P < .01) than those given the PEG or maize diets. Condensed tannins affected meat color, which was lighter (L*) than meat from lambs given the PEG-containing diet (P < .01). Sensory evaluation showed that panelists preferred meat from lambs receiving PEG and maize treatments compared with those receiving the tannin diet, and this could be related to differences in meat ultimate pH and carcass fatness. These results show that condensed tannins from carob pulp are very detrimental to feed digestibility and lamb performance. Inclusion of 40 g of PEG/kg diet eliminated the effects of condensed tannins so that lamb performance and meat quality were similar to lambs given a maize-based diet.

Over the last two decades, in situ techniques have been used extensively for measuring ruminal degradation of feedstuffs. Current predictive models put renewed emphasis on the need for quantitative information regarding rates and extents of ruminal degradation. However, in situ techniques suffer from tremendous variation, both within and among laboratories. A considerable number of studies have evaluated the influence of various factors on in situ-derived estimates of ruminal degradation. Factors that should be addressed in a standardized procedure include bag and sample sizes; bag material and pore size; sample processing; animal diet, feeding level, and frequency; bag insertion and removal procedures; location of bags within the rumen and containment procedures for the bags; rinsing procedures; microbial correction; incubation times; mathematical models; and numbers of replicate animals, days, and bags required to obtain repeatable estimates of ruminal degradation. Several recommendations that should increase the precision of in situ measurements are presented. Currently, the lack of standardization in rinsing techniques and the failure or inability to correct for microbial contamination of in situ residues seem to be the major sources of variability with in situ procedures.

We investigated the effects of dietary factors on the pH and the ammonia emission from slurry of growing-finishing pigs. Sixteen male hybrid pigs (80 to 90 kg BW) were allotted to one of four diets based on barley-wheat, tapioca, barley-tapioca, and sugar beet pulp. Diets were formulated to have similar NE and CP contents and a similar lysine:NE ratio. Diets differed in nonstarch polysaccharide content (NSP) and dietary electrolyte balance (dEB). Urine and feces were daily collected quantitatively in metabolism cages and mixed as a slurry at the end of the collection period. After mixing, the pH and the ammonia emission from the slurry were measured daily in a laboratory setup for 7 d at 20 degrees C. The type of diet affected the pH of the slurry and the ammonia emission (P < .001). The pH of the slurry from pigs fed the sugar beet pulp-based diet was .8 unit lower and ammonia emission was 52 to 53% lower than that of the other three diets. The low dEB and high NPS sugar beet pulp-based diet increased the VFA concentration and reduced the pH and ammonia emission from the slurry. We conclude that dietary NSP and dEB influence the pH and ammonia emission from slurry of growing-finishing pigs.

In situ experiments and two lamb digestion trials were conducted to evaluate the effects of chemically treating recycled newsprint (NP). Treatment of NP with 2% HCl (percentage of NP DM) followed by autoclaving for 4 h was most efficacious and was used in an in vivo digestion trial with 25 ram and wether lambs in a randomized complete block design (RCB). On a DM basis treatment diets were: 1) control, 95% alfalfa hay (AH); 2) 75% AH, 20% HCl-treated NP (HCl-NP); 3) 55% AH, 40% HCl-NP; 4) 75% AH, 20% untreated NP; and 5) 55% AH, 40% untreated NP on a DM basis. Lambs fed Treatments 2 and 3 had ad libitum DMI (1,043 and 1,036 g/d, respectively) similar to the DMI of those fed the control treatment (1,024 g/d); however, lambs fed Treatments 4 and 5 had lower (P < .05) ad libitum DMI (578 and 426 g/d, respectively) than lambs fed Treatments 1, 2, and 3. Apparent DM digestibilities were lower (P < .05) by lambs consuming Treatments 2, 3, 4, and 5 (52.6, 44.5, 52.0, and 48.2%, respectively) than by those consuming Treatment 1 (60.7%). Apparent OM, CP, NDF, and ADF digestibilities followed trends similar to DM. In the second digestion trial, 15 ram and wether lambs were used in a RCB to compare Treatments 1, 2, and 3. For this second digestion study, NP was treated with 4% HCl (percentage of NP DM), autoclaved for 4 h, and diets were fed at 2% of BW. As in Trial 1, apparent nutrient digestibilities decreased (P < .05) with increasing amounts of HCl-NP. Our results suggest that HCl-NP can be fed to sheep at 40% of the diet without a decrease in DMI; however, apparent nutrient digestibility decreases with increasing levels of HCl-NP.

Summary N a search for a more productive outlet I for the fibrous residues generated during commercial pulp and paper operations, repre­ sentative residues were screened for their potential as feedstuffs for ruminants, In vitro rumen digestibilities of many of the residues ranged from 45 to 60% ; some attained levels as high as 90%. Analytical data for Klason lignin, total carbohydrate, and ash constituents were also obtained. Four typical residues-screen rejects from the sulfite pulping of aspen, unbleached paren­ chyma cell fines from an aspen sulfite tissue mill, unbleached fines from a southern pine kraft mill, and bleached fines from a mixed hardwood southern kraft mill-wereobtained in sufficient quantity for feeding trials with goats, sheep, and steers. The residues were blended with other ration ingredients, and pelleted. In vivo digestibilities for the four residues are estimated to be 58, 52, 47 and 78%, respectively, indicative of substantial utilization of the available carbohydrate con­ stituents. A ration containing 77.4% paren­ chyma cell fines adequately maintained ewes for 2.5 months, and had good acceptability. Steers were fed rations containing 0 and 50% unbleached southern pine kraft pulp fines ad libitum for 58 days. Average daily gain was 0.77 and 0.54 kg, daily feed intake as a percent of body weight was 2.84 and 2.48, and feed/gain ratio was 9.44 and 11.69 for the 0 and 50% pulp rations, respectively. Rumen pH, ammonia, and volatile fatty acid ranged from 6.4 (0 pulp ration) to 6.6 (65% 1

It is generally recognized that the inorganic phosphate ingredients in mixed feed or mineral supplements are the principal source of fluoride in the feed. Today, there are several types of feed phosphates available to the feed industry. This paper discusses how these supplemental phosphates are produced, the quantities utilized by the feed industry and what species consume them, and describes their phosphorus content, fluoride content and general cost. The phosphate industry, along with university researchers and the Association of American Feed Control Officials, set up standards for safe levels of fluoride in feed phosphates. A P toF ratio of 100:1 was adopted in 1952 for any product sold to the feed industry as "defluorinated phosphate." The phosphate industry has felt that products with this ratio are safe, and, on the basis of evidence available today, it is still felt that this is a safe level of fluoride in supplemental feed phosphates. Industry has the technology to produce feed phosphates of lower fluoride content; however, there is an increased cost in further reducing fluoride content.

One hundred thirty New Zealand White x California rabbits were used to study the influence of the source of dietary fiber on several digestive criteria. Five diets were formulated to provide 10% crude fiber (CF) on a DM basis. Sixty percent of this dietary fiber was supplied by alfalfa hay, citrus pulp, beet pulp, grape marc, or rice hulls in the diets. Weights of cecal contents, cecal ammonia concentration, and molar proportion of acetic acid in diets including pulps were higher and cecal levels of DM, CP, and molar proportion of butyric acid were lower than those of the alfalfa diet. Cecal ammonia, VFA, and CF concentrations of the grape marc diet were the lowest of all the diets studied; cecal CF level and molar proportion of acetic acid were significantly higher and CP level and molar proportion of butyric acid were lower in rice hull than in alfalfa diets. Diet had no influence on daily soft feces excretion (10 g DM/d), but N contribution of soft feces to N intake was higher in the diet with citrus pulp (18.7%) than in the other diets (12%). Mean retention time (R) was measured using fuchsin-stained feed and was found to be higher (21.3 h) in the rice hull diet and lower (9.3 h) in the grape marc diet than in the other diets. When coprophagy was prevented, R decreased by 0 to 7 h. In conclusion, the use of byproducts to substitute for traditional sources of fiber in rabbit diets influenced the retention time of the digesta in some segments of the gut and thus altered several digestive criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Single cell protein (SCP) derived from secondary clarifiers of pulp mills is a potential commercial protein supplement in many areas. Samples of SCP were collected from several pulp mills in the Pacific Northwest and evaluated by laboratory procedures. Six in vivo digestion trials were conducted to determine the relative nutritive value of SCP that was dewatered by centrifugation or by the addition of a polyacrylamide polymer before being put through a belt press and dried with a sonic dehydrator. Amino acid analyses showed that SCP was higher in methionine than was cottonseed meal (CSM) and had a similar level of lysine. True protein, based upon amino acids recovered in SCP samples, ranged from 51.6 to 65.9% of the crude protein (CP). Pepsin digestibility of the CP ranged from 16.2 to 36.8%. Pepsin digestibility increased by 6.3 to 11.3 percentage units when SCP were incubated in a buffered rumen fluid for 24 hours. Solubility of the nitrogenous components in 10% Burroughs' buffer solution ranged from 12.4 to 36.5%. The range in mineral composition was : P, .62 to 1.55%; Ca, .14 to .99%; K, .21 to 5.52%; Mg, .07 to .59%. The concentration of trace minerals and heavy metals varied considerably from sample to sample. Digestion trials were conducted with sheep to compare SCP with CSM; 20 to 50% of the total CP was provided by the SCP sources. The CP digestibilities of the centrifuged and the polymer-dewatered SCP were 70.5 to 70.8% and 66.3 to 69.9%, respectively, of that observed for CSM. In all digestion trials, sheep consumed the SCP diets readily, and no digestive disturbances were observed. On the basis of laboratory and in vivo results, pulp mill SCP has the potential to be a viable protein supplement for livestock.