Are Bone Meal & Blood Meal toxic to dogs?

Blood meal can cause severe pancreatitis, while bone meal can form a cement-like foreign body in the stomach leading to gastrointestinal obstruction.

None of the sources describes a treatment written only for bone meal or blood meal: vets treat the signs and support the body. If your dog ate a large amount recently and has no signs yet, the vet usually makes it vomit to bring the meal up before it can clump. Activated charcoal isn't recommended, because it binds poorly to minerals. Care can then include anti-nausea medicine (once a blockage seems unlikely), stomach protectants, a bland digestive diet and IV fluids. For belly pain, an ASPCA Animal Poison Control toxicologist prefers opioids over anti-inflammatory painkillers (NSAIDs), which can irritate the gut further, and muscle relaxants for stiffness. Pancreatitis and bloat, which can follow when a dog gorges on bone and blood meal, are treated with the standard protocols. If the product contains iron, the vet calculates how much elemental iron your dog ate, may measure blood iron 4 to 6 hours after ingestion, and may give milk of magnesia or a chelating drug that binds iron. Pet Poison Helpline says surgery is only rarely needed after a dog eats bone meal, but when a stone-like mass forms and blocks the gut, it generally has to come out surgically. In a UK case series, surgery in two dogs with long-lasting signs found a blockage with a hole in the gut in one and dead tissue in the stomach wall in the other; both were put to sleep around the time of surgery because the outlook was poor.

Most dogs recover. In a UK series of 255 dogs that ate bone meal, reported to the Veterinary Poisons Information Service, 47.1% stayed well and 52.9% had signs, mostly vomiting and diarrhea; some were lethargic (14.9%) or had belly pain (5.9%). Signs were typically mild, but 1.2% developed a blockage and/or a hole in the gut. Of the 135 dogs with signs, 132 recovered, two were put to sleep and one died. An ASPCA Animal Poison Control toxicologist writes that most fertilizer ingestions can be managed easily, and that extremely large ingestions of blood, bone or fish meal may trigger pancreatitis in predisposed dogs but death is extremely rare. Pet Poison Helpline warns that a blockage or pancreatitis can be very serious and, in some cases, life-threatening. None of the sources gives outcome figures for blood meal.

• Bone meal, an organic garden fertilizer. It is made of animal bones that have been defatted, dried, flash-frozen and ground to a powder, and Pet Poison Helpline describes it as a mineral supplement high in calcium or phosphorus. Its N-P-K numbers (nitrogen, phosphorus, potassium) are often 0-12-0, reflecting the mineral make-up of bone.
• Blood meal, another organic fertilizer: dried, ground and flash-frozen blood, sold as a source of nitrogen and phosphorus. Pet Poison Helpline says it contains 12% nitrogen, that some types are fortified with iron, and that it is also used as a deer or rabbit repellent.
• Mixed organic fertilizers. Pet Poison Helpline groups bone, blood, fish and feather meal under one entry, and fertilizers can also contain iron, other minerals, herbicides, pesticides or fungicides, which add to the risk.
• Flower beds, bulb holes and rose beds. Bone meal is often added to the soil to help flowering bulbs grow, and fertilizer is often put in the planting hole, so dogs digging for it may eat the bulbs too. Around roses, many gardeners mix bone meal with disulfoton, a systemic insecticide, though an ASPCA Animal Poison Control toxicologist noted in 2016 that such very toxic insecticides were being replaced with safer ones.
• Open bags, buckets and spreaders. Significant ingestions usually happen when a bag or a spreader full of fertilizer is left where a dog can reach it, and some dogs eat bone meal straight out of the bag while their owner's back is turned. In one Pet Poison Helpline case, a puppy ate organic bone meal that neighbors had poured into a bucket while gardening.
• Dogs eat it for the smell. A UK case series says dogs are presumably attracted by the odor. Pet Poison Helpline says the bone is what makes bone meal so palatable, and that dogs can and will eat large quantities of these meals when given the chance. As one of its vets puts it, if a fertilizer smells bad, your dog will love it.

• Store bone meal, blood meal and other fertilizers out of your pet's reach. Significant ingestions usually happen when a bag or a spreader full of fertilizer is left where a dog can reach it, and some dogs eat bone meal straight out of the bag.
• Don't leave bone meal in a bucket or an open bag while you garden, and keep your pet away while you put it down.
• After applying bone meal, water the soil thoroughly several times before letting your pet back in the area, and watch whether it shows interest in the spot. For fish meal, blood meal and manure, a Pet Poison Helpline vet advises supervising your dog outdoors for at least a couple of days so it doesn't dig them up.
• Keep your dog from digging in beds where bone meal was used, including freshly planted bulbs. Pet Poison Helpline says the bone smell is what makes it so palatable, and dogs digging for fertilizer often eat the bulbs too.
• Know what's in the bag. Check the label for iron, and for an insecticide, herbicide or fungicide. A product that lists an EPA registration number, or a rose product with 'systemic' in its name, may contain one. Keep pets away from rose beds where an insecticide has been mixed with bone meal.
• Keep opened bags closed and out of reach too: fertilizer in opened packaging may carry mold toxins that cause tremors, even if it doesn't look moldy.