5 what's the best diet myths and truths

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Frances Harcourt‐Brown BVSc FRCVS, RCVS Recognised Specialist in Rabbit Medicine and Surgery

What’s the best diet- myths and truths


Origin of the domestic rabbit (Oryctolagus cuniculus)

• Originated in Iberian peninsula – hot, dry and arid for some of year

• Rabbits can exist in these conditions


All there is to eat in September


Introduction of rabbits to other countries

• Domesticated and kept in captivity for meat and fur

• Spread around the world by settlers who took and released them in new countries

• ‘Wild’ rabbits in Europe are descended from introduced rabbits


Worldwide distribution of Oryctolagus cuniculus


Effects of rabbits on landscape

• Eat virtually everything

• Destroy natural habitat

• Happened in UK before myxomatosis

• Even worse in Australia

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Control measures in Australia

Killed all rabbits on one side by various methods


Including poisons

• Dropped by helicopters or planes in baited food

Didn’t use poisonous plants


Supreme’s list of poisonous plants

Acokanthera fruit and flowersAconiteAfrican rueAgapanthusAgave (leaves)AlmondAloeAlsike cloverAmanita

Amaryllis belladonnaAndromedaAnemoneAngel's TrumpetAnthuriumAntirrhinumsApple (seeds)Apricot (all parts except fruit)Arrowgrass

Arrowhead vineAsian LillyAsparagus FernAtropa belladonnaAustralian NutAutumn CrocusAvacado (leaves)Azalea (leaves)

BaccharisBalsamBalsam Pear (seeds, outer rind of fruit)BaneberryBarbados LilyBeach peaBeargrassBeefsteak PlantBegoniaBelladonna Lily (bulbs)Betel‐nut PalmBird of Paradise (seeds)Bitter Cherry (seeds)Bittersweet (American & European)Bitterweed(s)

Black NightshadeBlack Walnut (hulls)BloodrootBluebonnetBluebellsBoston IvyBuddhist PineBusy LizzieButtercup (leaves)Black Locust (all parts)Black Nightshade (leaves and berries)Black RootBladderpodBleeding Heart (foliage and roots)Blue‐green Algae (some forms toxic)Bloodroot

Blue CohoshBog KalmiaBottlebrush (flowers)Boxwood (leaves,twigs)Bracken FernBranching IvyBroomcornBroomweedBryonyBuckeye (sprouts and seeds)Buckthorn (berries, fruit, bark)Bull NettleBunchberryBurroweedButtercups


And….

Cactus ThornCaesalpinia (seeds and pods)CaladiumCalendulaCalico Bush (young leaves and shoots)California FernCalifornia GeraniumCalifornia Holly (leaves)Calla Lilly (rhizome, leaves)Caladiur (leaves)Candelabra CactusCardinal FlowerCarnationCarolina JessamineCasava (roots and sap)Cassine (berries)Castor Bean (seed, leaves ‐ castor oil)CelastrusCentury PlantCerimanChalice Vine (all parts)Cherry, Jerusalem (fruits and leaves)Cherry Laurel

Cherry, Natal (berries)Cherry Tree (all parts)China DollChinaberry Tree (berries)Chinese BellflowerChinese LanternChinese EvergreenChoke Cherry (seeds)Christmas Berry (leaves)Christmas Candle (sap)Christmas RoseChrysanthemumCinerariaClematisClimbing NightshadeCloak FernCockleburCoffee BeanCohoshColorado RubberweedColumbineCommon PrivetCone Flower

Coral Berry (seeds)Coral Plant (seeds)CordatumCorn CockleCorn LilyCorn PlantCovotillo (berries)CowbaneCowslipCrab's Eye ‐ seedsCreeping Charlie (not the houseplant)Cress/crucifers/mustardCrocusCrotonCrow PoisonCrown of ThornsCrown VetchCuban LaurelCuckoopint (all parts)Curcas Bean (seeds and oil)Cutleaf PhilodendronCycadsCyclamen


And…

DaffodilsDahliasDaisyDaphne (berries, bark)Datura (berries)Day LilyDeadly NightshadeDeath Camas (all parts)Death CupDelphinium (all parts)

Deadly Amanita (all parts)Desert TobaccoDestroying AngelDevils TomatoDevil's IvyDianthusDieffenbachia (leaves)Dog MercuryDogwood (fruit)Doll's eyes (berries roots, foliage)

DogbaneDracaenaDracaena palmDragon treeDrymaryDurraDumb CaneDutchman's BreechesDutchman's pipe

Easter LillyEggplant (all but fruit)ElaineElderberry (unripe berries, roots, stems)Elephant Ear (leaves, stem)

Emerald dukeEmerald FeatherEnglish LaurelEnglish Ivy (berries, leaves)Euonymus

EuphorbiaEvening trumpetExotica perfectionEyebane

False HelleboreFalse Henbane (all parts)False ParsleyFiddle Leaf FigFiddleneck (fruit and bark)FigwortFirecracker

FirethornFireweedFlamingo PlantFlorida BeautyFlowering MapleFlowering TobaccoFluffy Ruffles

Fly AgaricFly‐poisonFool's ParsleyFour 0'clockFoxglove (leaves, seeds)FrijolitoFruit Salad Plant


And…

Garden SorrelGelsemiumGeraniumGerman IvyGhostweed (all parts)Giant DumbcaneGiant Touch‐me‐notGlacier Ivy

GladiolaGlecoma HederaceaGlory LillyGoatweedGold DieffenbachiaGold DustGolden Chain (all parts)

Golden PothosGolden‐toothed AloeGreasewoodGreen‐gold NephythytisGround IvyGroundsel(s)Guajillo

Hahn's IvyHalogetonHart IvyHawaiian Baby Wood RoseHawaiian TiHeartleaf PhilodendronHeart Ivy

Heavenly BambooHedge ApplesHelleboreHemlock, Poison (all parts)Hemlock, Water (all parts)Henbane (seeds)Hogwart

Holly (berries)Horse Chestnut (nuts, twigs)Horsehead PhilodendronHorsetail ReedHurricane PlantHyacinthHydrangea

ImpatiensIndian HempIndian LaurelIndian Rubber

Indian TobaccoIndian Turnip (all parts)IndigoInkberry

InkweedIrisIvy, Boston & English (berries, leaves)

Jack‐in‐the‐Pulpit (all parts)Jamestown weedJapanese EuonymusJapanese Show LilyJapanese YewJasmine

Jatropha ‐ seed and oilJava Bean (uncooked bean)Jequirity bean ‐ seedsJerusalem Cherry (berries)Jessamine

Jimmy fernJimson Weed (leaves, seeds)Johnson GrassJonquilJuniper (needles, stems, berries)

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And…

Kafir Kingcup Klamath weed

Laburnum (all parts)Lace FernLacy Tree PhilodendronLady SlipperLambkill (leaves)Lantana (immature berries)

Larkspur (all parts)Laurel (all parts)Laurel CherryLecheguillaLeyland CypressLigustrum

Lily of the Valley (all parts)Lima Bean (uncooked bean)Lobelia (all parts)Locoweed (all parts)Lords and Ladies (all parts)Lupine

Macadamia NutMachineelMadagascar Dragon TreeMajestyManchineel TreeMandrakeMarbel QueenMarijuana (leaves)Marsh MarigoldMauna Loa Peace LilyMayapple (all parts except fruit)Meadow Saffron

Medicine PlantMescal ‐ cactus topsMesquiteMexican BreadfruitMexicantesMescal Bean (seeds)Milk BushMilkvetchMilkweedMiloMiniature Croton

Mistletoe (berries)Moccasin FlowerMock Orange (fruit)Monkshood (leaves, roots)MoonflowerMoonseedMorning Glory (all parts)Mother‐in‐lawMountain LaurelMushrooms (some)Mustard (root)

NandinaNarcissusNeedlepoint Ivy

NephtytisNicotiana

Nightshades (berries, leaves)Nutmeg

There’s lots more


Burgess website

Some common plants that are harmful to rabbits: autumn crocus, begonia, black nightshade, busy lizzie, buttercup, carnation, chrysanthemum, clematis, cowslip, geranium, hemlock, laburnum, laurel, poison ivy, poppy and yucca.


An easy way to control rabbits?


Is plant toxicity a problem?

• No- rabbits are either resistant to toxin or they don’t eat the plant

• Finding plants they don’t eat is a problem

Cannabis


Reports of plant toxicity

• Reports of plant toxicity are in situations where rabbit has had nothing else to eat

• Could happen with houserabbit and houseplant

• Can worry about plant toxicity in that situation


What rabbits like to eat

?? Ground Elder

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Must rabbits have hay to eat?

Wild rabbits prefer grass


Is there anything that does poison rabbits

• Lead and heavy metals• Herbicides• Moulds- aflatoxins


Which of these is most likely to have been sprayed with chemicals


Which of these is most likely to go mouldy


Food for pet rabbits

• Lots of brands• Big variation between quality and suitability for pet rabbits

• Lots of competition between companies

• Lots of claims


Some advertising claims are hard to take…..

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Complete v complementary foods

• Complete foods are meant to fed on their own

• Complementary foods are meant to be fed with another food

• Rabbits need hay/grass• Muesli mix with no other food is the worst option


How commercial rabbit food is formulated

Information about nutritional requirements is taken from data about growth and reproductive performance of farmed rabbits


Pelleted food

• Are the way that most commercial rabbits are fed

• Easy to change analysis for life stages

• Give control of cost and efficiency of production

• Easy to store• Convenient• Can be medicated


Pellets and pet rabbits

• Superseded by muesli mixes

• Some good quality grass based pellets are available

• Mostly in US• Better than muesli mix


Nuggets

• Cooked, palatable biscuit• Stores well• Can incorporate long fibre strands- partially denatured by cooking

• Meant to be fed alongside hay• Nutritionally balanced• Fattening


Hay

Type and quality of hay depends on species of grass, soil, weather conditions when it was cut and how it is dried

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Hay for rabbits

• Lots of choice• If the rabbit eats it, then it is Ok


What about probiotics and prebiotics?

• Are in some brands of commercial rabbit food that contain prebiotics and probiotics

• ? Value• Supporting literature ahs shown they may improve

growth rate in commercial rabbits


Vitamin and mineral supplements and blocks

• Not necessary if rabbit is on a good diet

• Amount of calcium that is in them could be a problem for rabbits with urinary tract disease


Grass

• Grazing outside is perfect for rabbits

• Expensive to provide secure space

• Have to sacrifice any idea of growing flowers or veg

• Not an option for most people


?Poisonous plants


Foraging for rabbits

• Lots of free food, including grass on verges and alongside foot paths

• Won’t have been sprayed

• May be mowed, which is inconvenient

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Some examples of plants that my rabbits enjoy:

Dandelions Young docks Wild chervil

Ground elder Groundsel Hogweed


Foraging for rabbits

• Excellent book describing plants

• Available from Rabbit Welfare Association


Plants from veg garden

Fallen fruit, strawberry leaves, pea plants, artichokes, maize


Diet for healthy rabbits

NO MUESLI MIXES

Wild plants

Grass

Hay

Leaves

Branches

Tiny amount (or no) pellets or nuggets

Small amount fruit & root vegetables

Leafy greens

Herbs


BUT.. Surely you shouldn’t feed too many vegetables

• Breeders are worried about enteritis in juvenile rabbits

• Not surprising because enteritis is a problem

• Change of diet can trigger problems

• Breeders sometimes tell owners not to feed vegetables to their rabbit


Do plants and vegetables cause diarrhoea?

• ??? Maybe in rabbit colonies• Change of diet can cause

problems in young rabbits• Introduction of new veg can stop

an adult rabbit eating caecotrophs• Caecotrophs may be soft and

sticky • Owner thinks it has diarrhoea• So they stop feeding vegetables• Feed more nuggets instead

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What happens next?- A fat rabbit

• Too many nuggets and no vegetables ends up with obesity

• Main reason for not eating caecotrophs

• Not diarrhoea• Need to eat more vegand less (or no) concentrated food


Obesity

• Have to convince owners that there is a problem

• Try to get the to feel bad about feeding the rabbit instead of not feeding it

• If it has good teeth, it won’t starve on a diet of hay/grass and leafy greens


What about lettuce?

• I’ve never seen a problem with it


NO MUESLI MIXES

Wild plants

Grass

Hay

Leaves

Branches



Leafy greens

Herbs

Diet for rabbits with no incisors- may need food shredding or cutting up


Diet for rabbits with early dental disease (apical elongation)

Wild plants

Grass

Hay

Leaves

Branches



Leafy greens

Herbs &

Rabbits with apical elongation can’t/won’t eat hay

NO MUESLI MIXES


Wild plants

Grass

Hay

Leaves

Branches

Pellets or nuggets

Fruit & root vegetables

Leafy greens

Herbs


NO MUESLI MIXES

Diet for rabbits with advanced dental disease

Rabbits with deformed crowns can’t chew fibrous foods‐ could shred it

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Wild plants

Grass

Hay

Leaves

Branches

Pellets or nuggets

Fruit & root vegetables

Leafy greens

Herbs


NO MUESLI MIXES

Rabbits with deformed crowns can’t chew fibrous foods‐ could shred it

Diet for rabbits with endstage dental disease

Rabbits with no crowns struggle to eat


Rabbits with endstage dental disease

• Some rabbits eat very slowly

• Can live on nuggets• May need to be soaked• Nutritionally complete• Fibre content OK but not as good as hay/grass


Diet for obese rabbits with good teeth

Wild plants

Grass

Hay

Leaves

Branches



Leafy greens

Herbs

NO MUESLI MIXES


Diet for obese rabbits with endstage dental disease

Wild plants

Grass

Hay

Leaves

Branches



Leafy greens

Herbs

NO MUESLI MIXES


Obese rabbits with endstage dental disease

• Very difficult• Struggle to eat fibre- can choke

• Live on toast and banana

• Light diets are still fattening

• Shredded leafygreen plants and herbs


What about amount of calcium in diet?

• Amount of calcium in urine is related to amount of calcium in the diet

• This has been extrapolated to say that too much dietary calcium causes urinary tract disease

…. Not that simple

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Causes of urinary tract problems

• Encephalitozoon cuniculi• Spinal problems• Inactivity• Obesity• Physical problems preventing normal urination

• Pain preventing normal urination

• Etc. etc


Urine concentration

• Natural diet is leafy green plants that are mostly water

• High water intake dilutes urine

• So sediment is diluted if rabbit eats lots of leafy green veg

• Sediment not diluted if rabbit eats lots of dry food- including hay


Common advice for rabbits with urinary tract disease

• ‘Low calcium diets’ are often recommended to prevent or treat urinary tract disease

• Recommendation to avoid ‘high calcium veggies’

• It is sensible to restrict calcium but how?


Influence of water content on dietary calculations

• Recommended dietary calcium is 0.6-1%

• But actual calcium intake depends on how much food is eaten and how much water is in it.

• Concentrated foods- pellets/nuggets have 5-10% water

• Hay is 15% water

• Grass is 80% water

• Lettuce is 95% water

How much calcium does a rabbit need to consume each day?


Recommended daily allowance (RDA) of calcium

• RDA- recommended daily allowance

• Commercial rabbit pellets contain 0.8% calcium

• Pellets are 10% water so dry matter contains 90% x 0.8% = 0.72%

• Rabbits eat 63-95g pellets/day

• Consume 0.72% X 63-95g calcium

i.e 0.453-0.684g = 453-684mg

i.e. approximately 500mg


Calculating RDA (approximate figures)

• Commercial rabbit pellets contain 0.8% calcium

• Pellets are 10% water so dry matter contains 90% x 0.8% = 0.72%

• Rabbits eat 63-95g pellets/day• Consume 0.72% X 63-95g calciumi.e 0.453-0.684g = 453-684mgi.e. approximately 500mg

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Calcium content of foods

Food Calcium (Dry matter analysis)

Ca:P ratio

Apples 0.12% 1:1

Bananas 0.03% (0.06%) 1:30

Broccoli 0.48% 1:2

Cabbage 0.43% 2:1

Carrot tops 1.94% 10:1

Carrots 0.37% 1:1

Dandelions 1.87% 1:1

Lettuce 0.86% 2:1

Maize (sweetcorn) 0.04% 1:7

Oats 0.03% 1:11

Watercress 1.2% 2:1

Figures from a variety of books and websites.

Approximate values only


How much food would a rabbit need to eat to get 500mg calcium?

Equation to calculate amount of food (in grams) that provides 500mg calcium:

50% Calcium X % Dry matter


Amount of food to provides 500mg calcium

• 63g Burgess Suparabbit Excel (0.9%Ca)

• 65-159g Oxbow Bunny Basics (0.35-0.85% Ca)

63g nuggets


Amount of food item that provides 500mg calcium

1.6kg of lettuce 5.63kg of maizei.e. 3 lettuces ~10 cereal packets


Amount of food item that provides 500mg calcium

2 large pieces broccoli 15 apples


Amount of food to provides 500mg calcium

529g spring 631g spinach 1.13kg carrotscabbage~2 cabbages ~2.5 bags ~10-15 carrots

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Amount of food item that provides 500g calcium

• 20 bananas


‘High calcium veggies’

152g carrot tops 245g dandelions 256g kale( 2 bags)


Mineral blocks

• Weighs 55g• Contains 19% calcium and no

water• Calcium content 55X 19% =

10.45g • 1/20 block supplies RDA

(500mg) of for calcium


Grass

• Calcium content variable

• Depends on species of grass and soil type

• Usually around 0.5-0.6%

• 463g of grass if calcium content is 0.54%

Seems a lot…


But if you dry it out and separate it..

• Rabbits produce lots of hard faeces (180-200 per day)

• Have a large caecum that needs to be filled


Water content of grass that provides 500mg calcium

• 463g grass contains 350mls water

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‘Low calcium’ nuggets

63g nuggets

Could easily eat two bowlfuls and eat twice RDA of calcium


Amount of hay that provides 500mg calcium

• 143g grass hay (85% DM)‐ contains 21mls water

• 41g alfalfa hay (1‐2.07% calcium)‐ 6mls water

Hay may not be a good idea if rabbit has urinary tract problems. Not enough water


Water intake

• Water in take is important• More concentrated urine and

potentially more sediment if water intake is low

• Important that rabbits can drink plenty of water if they are fed on hay

• Not so important if they eat lots of greens

• Very important if they have urinary tract problems

Rabbits drink less from sipper

bottles.


Diet for rabbits with urinary tract problems

Wild plants

Grass

Hay

Leaves

Branches



Leafy greens

Herbs &

NO MUESLI MIXES

Rabbits with urinary tract disease need high fluid intake


Same diet for rabbits with early dental disease and urinary tract disease

NO MUESLI MIXESTiny amount pellets or nuggets


Leafy greens

Herbs

Wild plants

Grass

Hay

Leaves

Branches

Rabbits with urinary tract disease need high fluid intake

Rabbits with apical elongation can’t won’t eat hay


Grass and leafy greens are good for rabbits with urinary tract problems

• 463g grass contains 350mls water

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Grass and leafy green plants are preferred diet of rabbits

??

Provides right amount of calcium, water and fibre (plus many other benefits)


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5 what's the best diet myths and truths

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