Effects of low phosphorus supply on the availability of calcium and phosphorus, and musculoskeletal development of growing dogs of two different breeds.

To investigate the impact of a selective reduction in dietary phosphorus (P) supply on healthy growing dogs, a total of 23 Beagles and 30 Foxhound crossbreds (FBI) were used in a feeding trial between 6 and 24 weeks of age. Sixteen Beagles and 19 FBI were fed with selectively reduced P concentrations (low phosphorus, LP). The remaining puppies received a completely balanced control diet (CON). With these diets, the P supply in the Beagles at the age of 12 weeks added up to 2.5 ± 0.6 (LP) and 9.8 ± 1.4 g P/kg DM (CON), and in the FBI 4.3 ± 0.9 (LP) and 13.0 ± 1.6 g P/kg DM (CON). Therefore, the LP Beagles received an average of 33 ± 11% of the recommended daily allowances (RDA) of P, the LP FBI 41 ± 11%. The calcium (Ca) concentration stayed unaltered and led to a Ca/P ratio above the recommended range of 1.3/1 to 2/1. The apparent digestibility (aD) of phosphorus was reduced in the LP Beagle; otherwise, the aD of both minerals was not affected by the P concentration of the diet. The renal excretion of P was reduced to zero in both LP groups while the renal calcium excretion increased significantly. Several of the puppies from both breeds showed impaired appetite, growth, skin and fur quality, and a few also clinically showed relevant signs of a disturbed musculoskeletal system after the LP feeding. A rapid loss of muscle strength and posture within hours led to severe deviation of the limb axis with hyperflexion of the joints but no radiological aberrations or signs of pain. Immediate transition of affected puppies to a balanced diet with sufficient phosphorus resulted in a complete recovery of the puppies in less than one month. The results demonstrate the importance of an adequate P supply on the healthy development of growing dogs.

Renal energy excretion of horses depends on renal hippuric acid and nitrogen excretion.

The prediction of renal energy excretion is crucial in a metabolizable energy system for horses. Phenolic acids from forage cell walls may affect renal energy losses by increasing hippuric acid excretion. Therefore, the relationships were investigated between renal energy, nitrogen (N) and hippuric acid excretion of four adult ponies (230-384 kg body weight (BW)) consuming diets based on fresh grass, grass silage, grass cobs (heat-dried, finely chopped, pressed grass), alfalfa hay, straw, extruded straw and soybean meal. Feed intake was measured; urine and faeces were quantitatively collected for three days. Feed was analysed for crude nutrients, gross energy, amino acids and neutral-detergent-insoluble crude protein (CP); faeces were analysed for crude nutrients and cross energy; urine was analysed for N, hippuric acid, creatinine and gross energy. Renal energy excretion (y; kJ/kg BW0.75 ) correlated with renal N excretion (x1 ; g/kg BW0.75 ) and renal hippuric acid excretion (x2 ; g/kg BW0.75 ): y = 14.4 + 30.2x1 +20.7x2 (r = .95; n = 30; p < .05). Renal hippuric acid excretion was highest after intake of fresh grass and lowest after intake of soybean meal. The ratio of hippuric acid to creatinine in urine and the excretion of hippuric acid per gram of dry matter intake was significantly higher for fresh grass than for all other rations. There was no relationship between aromatic amino acid intake and renal hippuric acid excretion. The results of the present study and literature data suggest that feed can be categorized into four groups with regard to the energy losses per gram CP intake: (i) protein supplements (e.g., soybean meal): 4.2-4.9 kJ/g CP intake (ii) alfalfa hay, grains, dried sugar beet pulp: 6.4 kJ/g CP intake, (iii) hay, preserved grass products, straw: 5.2-12.3 kJ/g CP intake (mean 8) and (iv) fresh grass. For group (iii) a negative relationship was observed between renal energy losses per gram of CP and the content of CP or neutral-detergent-insoluble CP in dry matter.

A comparative meta-analysis on the relationship of faecal calcium and phosphorus excretion in mammals.

To investigate the relationship between faecal calcium (Ca) and phosphorus (P) excretion in different mammalian species, a meta-analysis on digestibility data derived from the literature was conducted. Seventy-three studies on carnivores, omnivores, large and small hindgut fermenters, ruminants and hippos (a total of 21 mammalian species, precondition for inclusion dietary Ca/P ratio 1.5/1 - 3.0/1) were analysed for Ca and P digestibility. Dietary Ca/P ratios were lower than faecal Ca/P ratios in carnivores, omnivores, ruminants and hippos. In hindgut fermenters, dietary Ca/P ratios were higher than faecal Ca/P ratios, indicating higher intestinal Ca absorption in these species. In all species investigated, there was a significant positive relationship between Ca intake and faecal Ca excretion and between P intake and faecal P excretion. In the biologically relevant range, these equations predicted lower faecal Ca losses in hindgut fermenters than ruminants, for faecal P vice versa. In all species, faecal Ca and P excretion correlated significantly. In carnivores, this highly linear correlation was exceptionally strong (R² = .92). Yet, the linearity of the correlation was questionable in omnivores and ruminants. Possibly, the strong linear correlation of faecal Ca and P excretion in carnivores is due to the formation of insoluble Ca/P complexes in their relatively short and simple gastrointestinal tract. Another hypothesis is that in carnivores, Ca homeostasis relies on modifying bone turnover to a higher degree than on changes in intestinal Ca absorption. For the formation of bone matrix, a constant ratio of Ca and P absorption is of advantage.

Demonstration of uniformity of calcium absorption in adult dogs and cats.

A meta-analysis was conducted to understand quantitative aspects of calcium (Ca) and phosphorus (P) absorption in adult dogs and cats. 34 studies in dogs and 14 studies in cats met the criteria for inclusion in the meta-analysis. Intake and faecal excretion values of Ca and P were subjected to a modified Lucas test and subsequent regression analyses. According to the current scientific consensus, Ca true digestibility (absorption) should increase at low Ca intake and decrease at high Ca intake. If true, this should result in a nonlinear relationship between the percentage of Ca excreted and dietary Ca intake. The present meta-analysis showed a highly significant linear relationship (p < 0.0001) between Ca intake and Ca excretion suggesting a lack of systematic quantitative adaptation in true Ca digestibility. This finding suggests either that the time period covered by standard digestion trials is too short to induce adaptation mechanisms or that dogs and cats at maintenance will not efficiently alter quantitative Ca absorption percentage according to the amount ingested. If the latter is true, a dietary Ca supply differing greatly from the recommended dietary intake might impair the health of cats and dogs when fed long term. The data plots for P intake and faecal excretion were less uniform suggesting other factors not just dietary intake influence faecal P excretion. In adult cats, the dietary Ca:P ratio strongly influenced the true digestibility of P, whereas this effect was less marked in adult dogs. Faecal P excretion was significantly correlated to faecal Ca excretion in both species (p < 0.0001), and surprisingly, the level of P intake did not appear to be an important determinant of true digestibility of P.

[Reduction of 137caesium contamination in wild boars by supplementing offered food with ammonium-iron-hexa-cyanoferrate]. / Reduktion der 137Cäsium-Aktivität in Wildschweinen durch Zusatz von Ammonium-Eisen-Hexacyanoferrat ("Berliner Blau") zum Kirrfutter.

OBJECTIVE: This replication study investigated whether the 137caesium (137Cs) contamination of wild boars could be relevantly reduced under field conditions by adding ammonium-iron-hexa-cyanoferrate (AFCF; Prussian blue) to the food. MATERIAL AND METHODS: In 285 wild boars that had been shot in six Bavarian hunting territories during the season (November until May) between 01 November 2010 and 10 December 2011 137Cs contamination was analysed. Thirty-five animals originated from two hunting territories in which offered food had been supplemented with 1250 mg AFCF per kilogram food. RESULTS: The control animals showed a mean 137Cs contamination of 522 Bq/kg lean skeletal muscle meat. Direct (univariable) comparisons of the two experimental territories with the four control territories yielded a mean reduction in 137Cs contamination due to Prussian bluefeeding by -211 Bq/kg (p < 0.001). Multivariable models that took potential confounders into account (age, weight, sex, hunting date, territory) estimated the effect to be -344 Bq/kg (p < 0.05). CONCLUSION AND CLINICAL RELEVANCE: This replication study confirmed the finding of Kienzle et al. (12) who described a statistically significant reduction in 137Cs contamination by -380 Bq/kg due to the feeding of Prussian blue in other territories.

[Nutritional laminitis--preventive measures for the obese horse]. / Fütterungsbedingte Rehe--Rezidivprophylaxe beim übergewichtigen Pferd.

Nutrition-induced laminitis is often caused by i) fermentation of large amounts of carbohydrates in the hindgut (usually fructans from grass or starch from cereals), which cause the release and absorption of microbial toxins and ii) insulin resistance induced by being overweight (equine metabolic syndrome). Both causes can act together. Overweight horses with a history of laminitis need to reduce body weight to prevent further incidences of laminitis. Weight reduction occurs normally on a diet of late-cut hay, a hay-straw mixture (maximally one third straw to prevent constipation) or grass seed straw all at 1-1.2% of ideal body weight. However, this roughage allowance does not satisfy the need of horses to chew, for which it requires at least 1.5% of ideal body weight. This may lead to behavioural issues, such as allophagia and aggression, and in extreme cases, stereotypic behaviour. Starch concentrates should not be replaced with high fat concentrates. Used saw dust is recommended for bedding. The intake of grass from a pasture has to be considerably and efficiently reduced. If the horse is extremely prone to laminitis or if stable management is unreliable, abstention from grazing is recommended. Any supplements need to be low in energy, and should supply minerals and vitamins which are deficient in the diet. Some additional protein or amino acids may be beneficial. Regular exercise, such as a daily 30-minute speedy trot, improves insulin sensitivity. Exercise increases energy expenditure to a certain extent, allowing a slight increase in the roughage supply, thus alleviating the conflict between energy reduction and fulfilling the need to chew. Weight loss should be 0.5-1% of body weight per week, while at a higher rate there is a potential risk of hyperlipemia. The effectiveness of the reducing diet should be monitored regularly, either by weighing or measuring body, neck or girth circumference (aiming for a reduction of 1-2 cm per week).

[Vitamin A excess by feeding with horse meat products containing high levels of liver]. / Vitamin-A-Exzess durch Pferdefleischprodukte mit hohen Leberanteilen.

OBJECTIVE: Horse meat is often used in the context of an elimination diet. For reasons of practicability some pet owners feed canned horse meat, which is commercially available. Based on a report of a cat with food allergy that displayed cervical spondylosis, the vitamin A content was analyzed in various horse meat products. MATERIAL AND METHODS: The vitamin A (retinol) content was analyzed in 14 commercially available horse meat products. The content of metabolizable energy was calculated on the basis of the declaration by using estimation equations. RESULTS: High amounts of vitamin A were found in some products for which liver, offal or animal by-products were labelled as contents. When feeding exclusively with one of these products, the vitamin A supply was just below the safe upper limit for cats while above the safe upper limit for dogs. CONCLUSION: Labelling and content of all-meat-products should be thoroughly checked to identify products with high liver percentages. CLINICAL RELEVANCE: An excessive vitamin A intake can occur when feeding with horse-meat products with a high liver content over a long period.

[Calcium deficiency: a problem in growing and adult dogs: two case reports]. / Kalziummangel - bei wachsenden und ausgewachsenen Hunden ein Problem. Zwei Fallberichte.

Two case reports demonstrate the consequences of a deficient calcium supply in dogs. The first case describes an adult dog with a history of food allergy. The dog had been fed with an unbalanced elimination diet (no minerals and vitamins supplemented) over many years and was referred with the diagnosis of osteomalacia (rubber jaw) for optimization of his ration. The second case refers to a puppy which was fed a homemade diet without supplementing the missing minerals and vitamins and suffered a femur fracture after moderate physical impact. In both cases, the computer-aided ration calculation showed a suboptimal to severely deficient supply for several minerals and vitamins, in particular calcium whereas serum calcium levels were normal. Both dogs recovered after being fed a complete and balanced diet. In conclusion, a survey of the feeding using ration calculation is essential especially in the case of potential nutrition-related skeletal disorders. Serum calcium levels cannot be used as a tool to diagnose nutritional calcium deficiency.

High calcium intake differentially inhibits nutrient and energy digestibility in two different breeds of growing dogs.

The current study was part of a larger investigation of two breeds of growing dogs (Dobenecker, 2002). The apparent digestibility of protein, fat, nitrogen-free extract (N-free extract) and organic matter as well as energy of a tripe and rice-based diet supplemented either with normal calcium [~1.1% dry matter (DM), normal calcium (NC)] or excess calcium [~3.6% DM, high calcium (HC)] was determined in two breeds of growing dogs of different sizes, including 30 Beagles and 44 Foxhound-Boxer-Ingelheim Labrador crossbred dogs (FBIs), at the ages of 12, 18 and 24 weeks. Apparent energy digestibility was significantly impaired by excess of calcium in both dog breeds, and the effect was stronger in FBIs than in Beagles (NC vs. HC in FBIs: 88.3 ± 2.6% vs. 84.7 ± 3.7%; NC vs. HC in Beagles: 89.0 ± 2.4% vs. 86.6 ± 3.4%; p < 0.05 in both FBIs and Beagles). The same was true for organic matter, N-free extract, crude protein and fat. The decrease in protein and fat digestibility was significant in FBIs, but not in Beagles. By contrast, the apparent digestibility of ash was lower in FBIs than in Beagles. Taken together, the results of the current study suggest that excess dietary calcium may be associated with systematic differences in nutrient digestibility by different breeds of dogs.

Mineral content of hay harvested in Bavarian and Swiss horse farms. Predictive value of cutting time, number of cut, botanical composition, origin and fertilization.

Hay samples from 29 horse farms in Southern Upper Bavaria and 31 horse farms in Switzerland were taken and analysed for minerals such as calcium, magnesium, phosphorus and potassium. The content of herbs and legumes in the hay was determined and the Weende analysis was performed. Comparison between Bavaria and Switzerland resulted in comparable calcium contents of approximately 4 g Ca/kg dry matter (DM) in grass hay. Hay with more than 10% of herbs and legumes found only in Switzerland showed higher Ca contents of >7 g Ca/kg DM in hay. The mineral contents of phosphorus and potassium were lower in hay from Switzerland (P: 1.8 +/- 0.7 g/kg DM, K: 15.4 +/- 5.1 g/kg DM) than from Bavaria (P: 3.8 +/- 0.6 g/kg DM, K: 20.0 +/- 6.0 DM), whereas the magnesium content of the hay showed no difference between the regions ( approximately 1.5 g Mg/kg DM). Very late first grass hay cuts showed low magnesium and calcium (<4 g/kg DM) contents. Further minerals in the hay for horses differed from those in dairy cattle in the same region. Fertilization showed only small effects on the mineral contents of the hay produced for horses. Therefore, in calculation of ration and production of supplements for horses, these differences should be taken into account.

Quantification of Enterobacteriaceae in faeces of captive black rhinoceros (Diceros bicornis) in relation to dietary tannin supplementation.

Free-ranging browsing herbivores ingest a range of secondary plant compounds, such as tannins, with their natural diet. As many of these substances have been shown to have antibacterial properties, it could be speculated that a lack of such compounds in captive zoo diets could favour the growth of potentially pathogenic intestinal bacteria. The effect of a supplementation of a conventional diet (N, consisting mainly of grass hay and/or lucerne hay and pelleted compound feeds) fed to eight captive black rhinoceroses (Diceros bicornis) from three zoological institutions with either tannic acid (T), a source of hydrolysable tannins, or quebracho (Q), a source of condensed tannins, was investigated. The number of faecal colony forming units (CFU) of Enterobactericeae was determined by colony count of dilution series from fresh faeces applied to MacConkey agar plates. Tannins were added to the diets at approximately 5-15 g/kg dry matter, depending on the varying intake of roughage and compound feeds by the animals. There was no difference in the number of CFU between diets N (95.0 x 10(5) +/- 225.3 x 10(5)/g fresh faeces) and T (164.3 x 10(5) +/- 225.1 x 10(5)/g fresh faeces); in contrast, diet Q led to a significant reduction in CFU (4.3 x 10(5) +/- 6.5 x 10(5)/g fresh faeces) compared with the other diets. These findings suggest that condensed tannins could have the potential to reduce the number of potentially pathogenic intestinal bacteria, and that the deliberate inclusion of tannin sources in the diets of captive wild animals should be further investigated. The fact that tannic acid, shown to have antibacterial effects in various in vitro studies, did not have an effect in this study, emphasizes that the relevance of tannin supplementation for intestinal health must be verified in vivo.

The influence of dietary tannin supplementation on digestive performance in captive black rhinoceros (Diceros bicornis).

Free-ranging browsers such as the black rhinoceros (Diceros bicornis) consume a diet that contains tannins, whereas the diets offered to them in captivity consist mostly of items known to contain hardly any such secondary plant compounds. Tannins could have potentially beneficial effects, including the chelation of dietary iron (iron storage disease is a common problem in black rhinos). Here, we tested the acceptance, and the consequences on digestion variables, of a low-dose tannin supplementation in captive animals. Eight black rhinoceroses from three zoological institutions were used. Faecal output was quantified by total faecal collection. Diets fed were regular zoo diets supplemented with either tannic acid (T, hydrolysable tannin) or quebracho (Q, condensed tannins); overall tannin source intake increased at 5-15 g/kg dry matter (DM) in relation to regular zoo diets. Adaptation periods to the new diets were >2 months. Additional data were taken from one hitherto unpublished study. Data were compared to measurements in the same animals on their regular zoo diets. All animals accepted the new diets without hesitation. There was no influence of tannin supplementation on digestion coefficients of DM and its constituents, or faecal concentrations of short-chain fatty acids or lactate. Water intake did not increase during tannin supplementation. Should the inclusion of dietary tannin sources be an objective in the development of diets for captive rhinoceroses, moderate doses such as used in this study are unlikely to cause relevant depressions of digestive efficiency and will not interfere with bacterial fermentation in a relevant way.

Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse.

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content [per 100 g dry matter (DM)], were compared with data for domestic horses. Rhinoceroses had significantly higher aA coefficients for Ca and Mg (because of a higher calculated 'true' absorption), and lower ones for Na and K (because of calculated higher endogenous faecal losses). High absorption efficiency for divalent cations is hypothesized to be an adaptation to a natural diet of particularly high Ca:P ratio (approximately 14:1); an effective removal of Ca from the ingesta guarantees sufficient P availability at the fermentation site in the hindgut. Higher faecal losses of Na and K are hypothesized to be linked to a higher faecal bulk per DM intake in black rhinoceroses as compared with horses because of a generally lower digestive efficiency. There were no relevant differences in the absorption patterns of microminerals. In particular, there were no discernable differences in Fe absorption within the rhinoceroses for diets with and without tannin supplementation. Several of the zoo diets assessed in this study were deficient in Cu, Mn or Zn, and most contained excessive levels of Fe when compared with horse requirements. The findings of this study indicate that differences in mineral absorption between occur even between species of similar digestive anatomy; that in particular, Ca absorption might vary between hindgut fermenters with Ca:P ratio in their natural diet; that Na might be a particularly limiting factor in the ecology of free-ranging rhinoceroses; that moderate doses of tannins do not seem to markedly influence mineral absorption; and that diets for captive animals should contain adequate, but not excessive mineral levels.

Antioxidant status of faeces of captive black rhinoceros (Diceros bicornis) in relation to dietary tannin supplementation.

In context with the frequent observations of excessive iron (Fe) storage in captive black rhinoceroses (Diceros bicornis), it has been suggested that both an excessive dietary Fe content and a lack of dietary Fe-chelating substances, such as tannins, is the underlying cause. Therefore, studies on the effects of tannin supplementation to captive diet are warranted. Six captive rhinoceroses were fed their normal zoo diet (N), and a similar diet supplemented with either tannic acid (T, hydrolysable tannin) or quebracho (Q, condensed tannins), and the total antioxidant capacity (TAC) was measured as mmol Trolox equivalents per kg fresh faeces. The TAC values on diets N (1.24 +/- 0.39 mmol/kg fresh faeces) and T (1.34 +/- 0.33 mmol/kg fresh faeces) were similar, but significantly higher on diet Q (2.32 +/- 0.61 mmol/kg fresh faeces). In contrast to expectations, faecal TAC increased with increasing faecal Fe, possibly as a result of the fact that the faecal Fe content was positively correlated to the proportion of concentrate feeds in the diet, which also contain antioxidants, such as vitamin E, in addition to Fe. Increased antioxidant status caused by the use of tannin substances could have a beneficial effect on animal health, but if tannins should be incorporated in designed diets, other tannin sources, such as grape pomace should be tested.

Studies on feed digestibilities in captive Asian elephants (Elephas maximus).

In order to test the suitability of the horse as a nutritional model for elephants, digestibility studies were performed with six captive Asian elephants on six different dietary regimes, using the double marker method with acid detergent lignin as an internal and chromium oxide as an external digestibility marker. Elephants resembled horses in the way dietary supplements and dietary crude fibre content influenced digestibility, in calcium absorption parameters and in faecal volatile fatty acid composition. However, the absolute digestibility coefficients achieved for all nutrients are distinctively lower in elephants. This is because of much faster ingesta passage rates reported for elephants. No answer is given to why elephants do not make use of their high digestive potential theoretically provided by their immense body weight. Differences in volatile fatty acid concentrations between these captive elephants and those reported from elephants from the wild are in accord with a reported high dependence of free-ranging elephants on browse forage.

Serum beta-carotene and alpha-tocopherol in horses fed beta-carotene via grass-meal or a synthetic beadlet preparation with and without added dietary fat.

The serum response of beta-carotene as an indicator of bioavailability was compared after feeding beta-carotene (0.8 mg/kg body weight) either from grass meal or a synthetic beadlet preparation (Lucarotin). Both were each given without or with added dietary vegetable fat (2-2.5% vs. 6.6% fat in dry matter) in a Latin square design with four horses. The nutritionally complete diet was supplemented with alpha-tocopherol (4 mg/kg body weight). Each treatment period (4 weeks, two serum samples) was followed by a washout period of 4 weeks with low intakes of beta-carotene (traces) and alpha-tocopherol (0.5 mg/kg body weight). Within 4 weeks of supplementation, serum beta-carotene increased about 10-fold, from a mean initial concentration of 0.05-0.53 micromol/l. There was no effect of beta-carotene source and of fat addition, respectively. Faecal excretion of beta-carotene ranged from 55 to 81% of intake. No beta-carotene was detected in any urine sample. Serum alpha-tocopherol (across all time points and animals, n=64) was 14.5 micromol/l. During supplementation, the values were significantly higher than during washout-periods. Additional dietary fat did not affect the serum response. Faecal excretion of alpha-tocopherol ranged from 69 to 121% of intake. Fat addition resulted in a significant decrease of serum cholesterol. In conclusion, the natural and the synthetic source of beta-carotene showed significant and identical bioavailability independent of additional fat.

Calculation of gross energy in pet foods: new data on heat combustion and fibre analysis in a selection of foods for dogs and cats.

Seven pectin samples, six galactomannan sources, five carrageen samples, four alginate samples, one sample of gum traganth, agar agar and gum arabicum, two xanthan samples, two inulin samples and a galacto oligosaccharide, 22 cellulose samples, six lignin samples, four starch samples, nine protein samples, six isolated fats, three meat samples, two lung samples, two samples of skimmed milk powder, 12 prepared complete dry dog foods, 21 moist dog foods, nine dry and 25 moist cat foods and 10 faecal samples were analysed for heat combustion (adiabatic bomb calorimetry), crude nutrients, acid detergent fibre (ADF), and acid detergent lignin (ADL). Some of the non-starch polysaccharides which gave low levels of crude fibre and ADF were also analysed for total, insoluble and soluble fibre. The heat combustion of cellulose ranged between 17.0 and 17.5 kJ/g organic matter (OM). The variation was somewhat larger for other non-starch polysaccharides (pectin, galactomannan sources, carageen, alginate, gums, xanthan, inulin) where heat combustion ranged between 14.0 and 18.2 kJ/g OM. The heat combustion of lignin averaged 25.5 kJ/g OM with considerable variation (17.0-29.2 kJ/g OM). Starch had a narrow range (17.2-17.3 kJ/g OM). Heat combustion of protein samples varied between 22.0 and 24.6 kJ/g, and of fat samples varied between 38.0 and 39.6 kJ/g OM. When cellulose was analysed for crude fibre only between 62 and 85% OM was detected. ADF analyses of cellulose ranged between 75 and 93% OM. The crude fibre content of all other non-starch polysaccharides did not exceed 13% OM, with the exception of pectins (ADF 0.7-37% OM) and alginates (ADF 39-66% OM), the ADF content was also below 13% in these samples. In contrast the total fibre content was above 80% OM in all non-starch noncellulose polysaccharides and the percentage of soluble fibre was high (25-93% OM). Unprocessed lignin gave high readings for crude fibre (39-61% OM) and ADF (96-99% OM), while processed lignin had low crude fibre content (< 1% OM) and low ADF content (< 32%). ADL determined unprocessed lignin (78-91% OM), but again processed lignin was analysed incompletely (< 29%). Pectin and alginate gave false positive ADL readings of up to 31% OM, while all other non-starch polysaccharides were not determined by ADL. When gross energy was calculated with the factors (kJ/g) 24 for protein, 38 for fat and 17 for all carbohydrate, including fibre, there was a good correlation between calculated gross energy and heat combustion in 67 pet foods as well as in meat, lung and skimmed milk powder. In contrast to this the same factors underestimated heat combustion of faeces by around 8%.

Factorial calculation of nutrient requirements in lactating queens.

The energy, protein, calcium and phosphorus requirements of lactating queens were estimated by using the factorial method. Requirement values for protein and energy were divided into requirements for maintenance and for milk production. For maintenance, existing data were used. For milk production, the net requirements were calculated by summing the energy and protein losses in milk; the gross requirements were then estimated taking into account the utilization of metabolizable energy (ME) for milk production and the digestibility of protein and its utilization for milk production. Net maintenance requirements for calcium and phosphorus were calculated from endogenous fecal, renal and cutaneous losses. Losses in milk were added. For calculation of gross calcium and phosphorus requirements, utilization was estimated from true digestibility under suboptimal, but not extreme conditions. For queens with large litters at the peak of lactation, the following estimated requirements were derived (per kg body weight): 0.81 MJ ME, 14 g protein, 428 mg calcium and 303 mg phosphorus.