Analyze Diet

Topic:Feeding Trial

Feeding trials in horses are controlled studies designed to evaluate the effects of different diets or nutritional strategies on equine health and performance. These trials systematically assess various dietary components, such as protein, fiber, vitamins, and minerals, to determine their impact on parameters like weight gain, digestive efficiency, and overall well-being. Participants in these studies may include horses of different breeds, ages, and activity levels to provide comprehensive insights. The data collected from feeding trials contribute to the development of evidence-based dietary recommendations and nutritional guidelines. This page compiles peer-reviewed research studies and scholarly articles that investigate the methodologies, outcomes, and implications of feeding trials in equine nutrition.
Influence of maternal plane of nutrition on mares and their foals: determination of mare performance and voluntary dry matter intake during late pregnancy using a dual-marker system.
Journal of animal science    July 3, 2013   Volume 91, Issue 9 4208-4215 doi: 10.2527/jas.2013-6373
Winsco KN, Coverdale JA, Wickersham TA, Lucia JL, Hammer CJ.Thirty pregnant mares (538 to 695 kg BW; 4 to 19 yr of age) were used to evaluate the effects of plane of nutrition on DMI of hay and mare performance (BW, BCS, and rump fat) during the last third of pregnancy. Mares were divided into 4 blocks by their expected foaling date and randomly assigned within block to either a hay or concentrate plus hay diet (concentrate fed at 0.75% BW, as-fed basis) with 15 mares per treatment. Treatments began 110 d before expected foaling date (230 d of gestation) and terminated at parturition. Mares were housed by block and allowed ad libitum access to coastal ...
The development and evaluation of a mathematical nutrition model to predict digestible energy intake of broodmares based on body condition changes.
Journal of animal science    February 19, 2013   Volume 91, Issue 5 2169-2177 doi: 10.2527/jas.2011-4659
Cordero VV, Cavinder CA, Tedeschi LO, Sigler DH, Vogelsang MM, Arnold CE.Mathematical nutrition models have been developed for beef and dairy cattle to estimate dietary energy intake needed to change BCS. Similar technology has not been used to improve nutrition and feeding strategies for horses. An accurate equine nutrition model may enhance feeding management and reduce the costs of unnecessary overfeeding and promote an optimal level of fatness to achieve reproductive efficiency. The objectives of this study were to develop and evaluate a mathematical nutrition model capable of accurately predicting dietary energy changes to alter BW, rump fat (RF) thickness, an...
Adaption of horses to a novel dynamic feeding system: movement and behavioural responses.
Equine veterinary journal    December 6, 2012   Volume 45, Issue 4 481-484 doi: 10.1111/evj.12002
Hampson BA, de Laat MA, Monot J, Bailliu D, Pollitt CC.Many domestic horses and ponies are sedentary and obese due to confinement to small paddocks and stables and a diet of infrequent, high-energy rations. Severe health consequences can be associated with this altered lifestyle. Objective: The aims of this study were to investigate the ability of horses to learn to use a dynamic feeder system and determine the movement and behavioural responses of horses to the novel system. Methods: A dynamic feed station was developed to encourage horses to exercise in order to access ad libitum hay. Five pairs of horses (n = 10) were studied using a randomised...
Effect of long-term feed restriction on the health status and welfare of a robust horse breed, the Shetland pony (Equus ferus caballus).
Research in veterinary science    November 8, 2012   Volume 94, Issue 3 826-831 doi: 10.1016/j.rvsc.2012.10.010
Brinkmann L, Gerken M, Riek A.Outdoor group housing is increasingly recognized as an appropriate housing system for domesticated horses. The objective of this study was therefore to investigate the effect of potential feed shortage in semi-natural horse keeping systems in winter on animal health and welfare. In 10 female Shetland ponies blood concentrations (NEFA, total protein (TP), total bilirubin (TB), beta-hydroxybutyrate (BHB) and thyroxine (T4)), body mass and the body condition score (BCS) were monitored for 7 months including a 4 months period of feed restriction in five of the 10 ponies. Restrictively fed animals ...
Highly deoxynivalenol contaminated oats and immune function in horses.
Archives of animal nutrition    May 31, 2012   Volume 66, Issue 2 149-161 doi: 10.1080/1745039x.2012.672220
Khol-Parisini A, Hellweg P, Razzazi-Fazeli E, Saalmüller A, Strasser A, Tichy A, Zenteke J.The aim of the present study was to investigate the impact of deoxynivalenol (DON) on cellular and humoral immune parameters in horses. A feeding trial using naturally contaminated oats with high (20.2 mg/kg) and low (0.49 mg/kg) levels of DON was conducted. Two groups of five mares were fed 2 kg oats daily with high or low DON levels for two weeks, using a crossover design with a three-week wash-out period. No adverse effects on general health were observed. Only minor diet-related changes in differential blood counts and serum biochemistry were noted. Serum haptoglobin concentration was sign...
Apparent digestibility of wheat bran and extruded flax in horses determined from the total collection of feces and acid-insoluble ash as an internal marker.
Animal : an international journal of animal bioscience    March 23, 2012   Volume 6, Issue 2 227-231 doi: 10.1017/S1751731111001297
De Marco M, Miraglia N, Peiretti PG, Bergero D.Several studies have reported data on comparisons between two methods: the total collection of feces and the internal markers method. The aim of this study was to assess the apparent digestibility of two concentrates and to compare the apparent digestion coefficients using the total collection of feces and acid-insoluble ash (AIA) as the internal marker method. In 2009, six adult geldings aged between 3 and 11 years, with an average weight per trial of 543, 540 and 542 kg, respectively, were used to determine the apparent digestibility by means of three in vivo digestibility trials on hay, hay...
Effects of high and moderate non-structural carbohydrate hay on insulin, glucose, triglyceride, and leptin concentrations in overweight Arabian geldings.
Journal of animal physiology and animal nutrition    May 16, 2011   Volume 96, Issue 3 428-435 doi: 10.1111/j.1439-0396.2011.01159.x
Shepherd ML, Pleasant RS, Crisman MV, Werre SR, Milton SC, Swecker WS.The objective of this study was to determine the effects of high and moderate non-structural carbohydrates (NSC) hay on insulin, glucose, triglyceride, and leptin concentrations in overweight Arabian geldings. Eight adult overweight (average BCS 7 [9-point scale]) Arabian geldings were fed each of two orchardgrass hays, high NSC (18% DM) and moderate NSC (12% DM), in a cross over design during two 28-day periods. Body weight and body condition score assessment along with blood sampling to measure insulin, glucose, leptin, and triglyceride concentrations were performed on days 0, 7, 14, 21 and ...
Influence of dietary methionine concentration on growth and nitrogen balance in weanling Quarter Horses.
Journal of animal science    February 25, 2011   Volume 89, Issue 7 2132-2138 doi: 10.2527/jas.2010-3380
Winsco KN, Coverdale JA, Wickersham TA, Shelton JL.Twenty-four Quarter Horse weanlings (120 ± 10 d) were blocked by age into 4 groups (n=6) for a 56-d trial to evaluate the influence of dietary Met concentration on growth and N balance. Weanling horses were housed by block and individually fed concentrates twice daily at 1.75% BW (as-fed basis). Weanling horses were randomly assigned to 1 of 4 concentrate treatments: basal (0.20 Met), basal + 0.03% Met (0.23 Met), basal + 0.07% Met (0.27 Met), and basal + 0.11% Met (0.31 Met). Diets were formulated to be isonitrogenous and isocaloric and contained equal amounts of Lys and Thr. Coastal bermuda...
Motivation for hay: effects of a pelleted diet on behavior and physiology of horses.
Physiology & behavior    September 24, 2010   Volume 101, Issue 5 623-627 doi: 10.1016/j.physbeh.2010.09.010
Elia JB, Erb HN, Houpt KA.The natural diet of free-ranging horses is grass, which is typically high in fiber and calorically dilute, however diets for high performance domestic horses are often low in fiber and calorically dense. The aim of the study was to determine the motivation of horses for hay when fed a low roughage diet. Their motivation could be used to determine if low roughage diets compromise the welfare of horses. Eight mares were fed two different diets in counterbalanced order: ad libitum orchard grass hay; a complete pelleted feed (pellets). Each trial lasted three weeks, with a one-week transition peri...
Comparison of in vitro digestibility estimates using the DaisyII incubator with in vivo digestibility estimates in horses.
Journal of animal science    August 13, 2010   Volume 88, Issue 12 3954-3963 doi: 10.2527/jas.2010-2989
Earing JE, Cassill BD, Hayes SH, Vanzant ES, Lawrence LM.The objective of this study was to determine if in vitro methodologies developed for the Ankom Daisy(II) incubator could produce accurate estimates of in vivo equine DM digestibility (DMD) and NDF digestibility (NDFD) when equine feces were used as the inoculum source. Four mature geldings were utilized in a 4 × 4 Latin square design experiment with a 2 × 2 factorial arrangement of dietary treatments (timothy hay, alfalfa hay, timothy hay plus oats, and alfalfa hay plus oats), in which the geldings were individually housed and fed. During each 5-d total fecal collection period, feces were co...
Comparative ingestive mastication in domestic horses and cattle: a pilot investigation.
Journal of animal physiology and animal nutrition    July 29, 2010   Volume 94, Issue 6 e402-e409 doi: 10.1111/j.1439-0396.2010.01030.x
Janis CM, Constable EC, Houpt KA, Streich WJ, Clauss M.It is often assumed that horses chew food more intensively during ingestion than cattle, which - as ruminants - complete part of the mastication during rumination. This has been proposed as a reason for more robust mandibles, larger masseter insertion areas and larger masseter muscles in horses as compared to cattle and other grazing ruminants. In this study, we evaluate results of comparative feeding trials with three horses (338-629 kg) and three cows (404-786 kg), on four different roughages. Ingestion time (s/g dry matter) and chewing intensity (chews/g dry matter) differed among animals w...
Digestibility and nutrient retention of perennial peanut and bermudagrass hays for mature horses.
Journal of animal science    February 12, 2010   Volume 88, Issue 6 2055-2061 doi: 10.2527/jas.2009-2092
Eckert JV, Myer RO, Warren LK, Brendemuhl JH.Mature horses were used to determine apparent DM, OM, NDF, and CP digestibility values of 2 bermudagrass (BG; Cynodon dactylon) hays, Coastal (CB) and Tifton 85 (T85), and Florigraze perennial peanut (PP; Arachis glabrata) hay. In addition, N, Ca, and P balances were determined in horses fed those hays. Five mature Thoroughbred geldings and 1 Quarter Horse gelding (mean initial BW = 542 +/- 37 kg) were used (5 horses for the last period) in a 3 x 3 repeated Latin square design, with 2 horses per hay and 3 adjustment and collection periods. Horses were randomly assigned to pairs and the initial...
A comparison between the 2N and 4N HCl acid-insoluble ash methods for digestibility trials in horses.
Animal : an international journal of animal bioscience    December 1, 2009   Volume 3, Issue 12 1728-1732 doi: 10.1017/S1751731109990656
Bergero D, Préfontaine C, Miraglia N, Peiretti PG.The digestibility of horse feeds and rations can be determined using different techniques such as calculations based on the chemical composition, in vivo or in vitro methods. The marker methods overcome difficulties like discomfort for the animals and longer experimental times encountered using the ingesta/egesta method. In field conditions, a natural indigestible marker like acid-insoluble ash (AIA), with no changes in the normal ration, could be a very useful tool for digestibility trials. A group of six standardbred horses was used in a set of seven apparent digestibility trials. The diets ...
Impact of feeding level on digestibility of a haylage-only diet in Icelandic horses.
Journal of animal physiology and animal nutrition    November 17, 2009   Volume 94, Issue 5 623-627 doi: 10.1111/j.1439-0396.2009.00947.x
Ragnarsson S, Lindberg JE.Eight mature Icelandic geldings were used in an experiment arranged as a change-over design to evaluate the effect of feeding level on the digestibility of a high-energy haylage-only diet. The horses were fed a low feeding level 10.7 g dry matter (DM)/kg body weight (BW) (maintenance) and a high feeding level 18.1 g DM/kg BW (1.5 × maintenance) during two 23 days experimental periods. Total collection of faeces was performed for 6 days at the end of each period to determine the coefficient of total tract apparent digestibility (CTTAD). The CTTAD for DM, organic matter, neutral detergent fibre...
Effect of type of grain and feed processing on gastrointestinal retention times in horses.
Journal of animal science    August 14, 2009   Volume 87, Issue 12 3991-3996 doi: 10.2527/jas.2008-1150
Rosenfeld I, Austbø D.Gastrointestinal retention time may affect digestive processes in the horse. To evaluate the effect of processing of grains on mean retention time in different segments of the gastrointestinal tract, 4 Norwegian Cold-blooded trotters (cecally cannulated, approximately 500 kg of BW) were used. Barley, maize, and wheat were all ground, pelleted, extruded, and micronized to create a total of 12 processed grains. After an adaptation period of 5 d, each horse was given 0.2 kg of Yb-mordanted grain together with their morning meal, which consisted of 2 kg of hay and 1 kg of one of the grains. Fecal ...
Feeding management of elite endurance horses.
The Veterinary clinics of North America. Equine practice    March 24, 2009   Volume 25, Issue 1 137-viii doi: 10.1016/j.cveq.2009.01.005
Harris P.This article reviews the principles of feeding management for endurance horses. The amount and type of dietary energy (calories) are key considerations in dietary management, because (1) there is evidence that the body condition score, an indicator of overall energy balance, influences endurance exercise performance, and (2) the source of dietary energy (ie, carbohydrate versus fat calories) impacts health, metabolism, and athletic performance. Optimal performance is also dependent on provision of adequate feed, water, and electrolytes on race day.
Mineral absorption in tapirs (Tapirus spp.) as compared to the domestic horse.
Journal of animal physiology and animal nutrition    January 13, 2009   Volume 93, Issue 6 768-776 doi: 10.1111/j.1439-0396.2008.00865.x
Clauss M, Lang-Deuerling S, Kienzle E, Medici EP, Hummel J.To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for tapirs (Tapirus spp.), we investigated the apparent absorption (aA) of macro and micro-minerals in 18 tapirs from five zoological institutions in a total of 24 feeding trials with total faecal collection. Samples of feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Cu and Zn. The resulting aA coefficients and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content (per 100 g dry matter) were compared with data for domestic horses. W...
Voluntary intake and digestibility in horses: effect of forage quality with emphasis on individual variability.
Animal : an international journal of animal bioscience    October 1, 2008   Volume 2, Issue 10 1526-1533 doi: 10.1017/S1751731108002760
Edouard N, Fleurance G, Martin-Rosset W, Duncan P, Dulphy JP, Grange S, Baumont R, Dubroeucq H, Pérez-Barbería FJ, Gordon IJ.Food intake is a key biological process in animals, as it determines the energy and nutrients available for the physiological and behavioural processes. In herbivores, the abundance, structure and quality of plant resources are known to influence intake strongly. In ruminants, as the forage quality declines, digestibility and total intake decline. Equids are believed to be adapted to consume high-fibre low-quality forages. As hindgut fermenters, it has been suggested that their response to a reduction in food quality is to increase intake to maintain rates of energy and nutrient absorption. Al...
The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production.
Journal of animal physiology and animal nutrition    August 12, 2008   Volume 93, Issue 5 631-638 doi: 10.1111/j.1439-0396.2008.00848.x
Vervuert I, Voigt K, Hollands T, Cí·¯ord D, Coenen M.The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three d...
The relationship between cheek tooth occlusal morphology, apparent digestibility, and ingesta particle size reduction in horses.
Journal of the American Veterinary Medical Association    August 5, 2008   Volume 233, Issue 3 452-455 doi: 10.2460/javma.233.3.452
Carmalt JL, Allen A.To investigate potential relationships between cheek tooth occlusal morphology, apparent feed digestibility, and the reduction in feed particle size that occurs during digestion in horses. Methods: Cross-sectional study. Methods: 17 horses of various ages and breeds and either sex. Methods: Horses were fed 1 of 3 hay-based diets ad libitum for 14 days prior to euthanasia; nutrient analysis was performed on samples of each of the 3 diets. At the time of postmortem examination, the head was disarticulated, photographs were taken of the occlusal surfaces of the maxillary and mandibular cheek toot...
Stringhalt in Brazilian horses caused by Hypochaeris radicata.
Toxicon : official journal of the International Society on Toxinology    May 29, 2008   Volume 52, Issue 1 190-193 doi: 10.1016/j.toxicon.2008.04.164
Araújo JA, Curcio B, Alda J, Medeiros RM, Riet-Correa F.Two outbreaks of Hypochaeris radicata-induced Australian stringhalt involving two farms and seven horses from southern Brazil are reported here. Subsequently, the disease was experimentally reproduced in a feeding trial with one colt fed H. radicata from the suspect paddocks. Fresh H. radicata was fed to the experimental animal for 50 days at an average daily dosage of 9.8 kg. Initially, the plant was collected from the paddock where the clinical disease occurred and was fed for 19 consecutive days producing mild clinical signs. However, on days 20-23 fresh plant was collected from a neighbori...
Effects of processing barley on its digestion by horses.
The Veterinary record    May 27, 2008   Volume 162, Issue 21 684-688 doi: 10.1136/vr.162.21.684
Vervuert I, Voigt K, Hollands T, Cí·¯ord D, Coenen M.Four horses were randomly fed a diet containing rolled, micronised or extruded barley; the barley intake was adjusted to supply 2 g starch/kg bodyweight per day. During a 10-day acclimatisation period the horses were also fed 1 kg grass hay/100 kg bodyweight per day. Samples of blood and breath were collected at the end of each period after the test meal of barley had been fed after a 12-hour overnight fast. The glycaemic and insulinaemic responses of the horses were measured as an indication of the pre-caecal digestibility of starch, and postprandial breath hydrogen and methane were measured ...
Evacuation of sand from the equine intestine with mineral oil, with and without psyllium.
Journal of animal physiology and animal nutrition    January 11, 2008   Volume 92, Issue 1 86-91 doi: 10.1111/j.1439-0396.2007.00713.x
Hotwagner K, Iben C.The aim of this study was to determine the evacuation of sand from the equine intestine after a double treatment with psyllium and mineral oil or mineral oil only. A crossover study was conducted. Twelve healthy horses were fed 1 kg sand once a day for 5 days. Subsequently, these horses were divided into two groups: A and B. From day 6-10, both groups were treated with 2 l of mineral oil once a day and group B received an additional 0.5 kg of psyllium twice a day. The trial was repeated after 2 weeks with treatment crossover of groups A and B. The horses were housed sand free and 1.8 kg hay/10...
Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse.
Journal of animal physiology and animal nutrition    May 23, 2007   Volume 91, Issue 5-6 193-204 doi: 10.1111/j.1439-0396.2007.00692.x
Clauss M, Castell JC, Kienzle E, Schramel P, Dierenfeld ES, Flach EJ, Behlert O, Streich WJ, Hummel J, Hatt JM.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...
How should we feed horses–and how many times a day?
Veterinary journal (London, England : 1997)    March 30, 2007   Volume 173, Issue 2 252-253 
Harris PA.No abstract available
Effects of feeding sunflower oil or seal blubber oil to horses with recurrent airway obstruction.
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire    December 30, 2006   Volume 71, Issue 1 59-65 
Khol-Parisini A, van den Hoven R, Leinker S, Hulan HW, Zentek J.A crossover feeding trial was performed with 9 horses suffering from recurrent airway obstruction (RAO). The study aimed to determine whether ingestion of sunflower oil (SFO), rich in linoleic acid, or seal blubber oil (SBO), a source of long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs), changes the fatty acid (FA) ratios in plasma and leukocyte membrane phospholipids (PLs) or the leukocyte numbers or proportions of cell types in the airways. We also investigated diet-related changes in respiratory rate, maximum change in pleural pressure (deltaPpl(max)), dynamic compliance (C(dyn)...
Fall panicum (Panicum dichotomiflorum) hepatotoxicosis in horses and sheep.
Journal of veterinary internal medicine    December 26, 2006   Volume 20, Issue 6 1414-1421 doi: 10.1892/0891-6640(2006)20[1414:fppdhi]2.0.co;2
Johnson AL, Divers TJ, Freckleton ML, McKenzie HC, Mitchell E, Cullen JM, McDonough SP.Fourteen horses at a boarding stable in Virginia were diagnosed with hepatic disease and locally grown hay was implicated as the cause. Objective: Panicum dichotomiflorum, the predominant grass species in the hay, is hepatotoxic to horses. Methods: Naturally occurring cases were adult horses of various breeds. Two healthy adult horses and 2 healthy adult sheep were used in feeding trials. Methods: Blood and liver specimens collected from affected animals during the outbreak were analyzed. Some of the affected animals were treated supportively; the main intervention was hay withdrawal. Feeding ...
Meal size and feeding frequency influence serum leptin concentration in yearling horses.
Journal of animal science    August 16, 2006   Volume 84, Issue 9 2391-2398 doi: 10.2527/jas.2005-281
Steelman SM, Michael-Eller EM, Gibbs PG, Potter GD.Energy is an essential nutrient for all horses, and it is especially important in performance horses, pregnant and lactating mares, and young growing horses. A negative energy balance in horses such as these may result in unsatisfactory performance, decreased fertility, or slow growth. Therefore, ensuring adequate energy intake is an important aspect of the nutritional management of the equine. This study was undertaken to investigate the effects of feeding large, carbohydrate-rich, concentrate meals on the satiety-inducing hormone, leptin. Three groups of yearling horses were rotated through ...
Effect of selenium supplementation and source on the selenium status of horses.
Journal of animal science    June 16, 2006   Volume 84, Issue 7 1742-1748 doi: 10.2527/jas.2005-413
Richardson SM, Siciliano PD, Engle TE, Larson CK, Ward TL.This study was conducted to determine the effect of Se supplementation and source on the Se status of horses. Eighteen 18-mo-old nonexercised horses were randomly assigned within sex to 1 of 3 treatments: 1) control (CTRL, no supplemental Se, 0.15 mg of Se/kg of total diet DM); 2) inorganic Se (INORG, CTRL + 0.45 mg of Se/kg of total diet DM from NaSeO3); or organic Se [ORG, CTRL + 0.45 mg of Se/kg of total diet DM from zinc-L-selenomethionine (Availa Se, Zinpro, Corp., Eden Prairie, MN)]. Horses were acclimated to the CTRL diet (7.1 kg of DM alfalfa hay and 1.2 kg of DM concentrate per horse ...
Effect of feeding a DHA-enriched nutriceutical on the quality of fresh, cooled and frozen stallion semen.
Theriogenology    February 24, 2005   Volume 63, Issue 5 1519-1527 doi: 10.1016/j.theriogenology.2004.07.010
Brinsko SP, Varner DD, Love CC, Blanchard TL, Day BC, Wilson ME.Eight stallions were used in 2 x 2 crossover study to determine if feeding a nutriceutical rich in docosahexaenoic acid (DHA) would improve semen quality. Stallions were randomly assigned to one of two treatment groups (n = 4 per group). Stallions were fed their normal diet (control) or their normal diet top-dressed with 250 g of a DHA-enriched nutriceutical. Feeding trials lasted for 14 week, after which a 14-week washout period was allowed and the treatment groups were reversed for another 14 week feeding trial. Feeding the nutriceutical resulted in a three-fold increase in semen DHA levels ...