Meat By-Products
Last updated: February 10, 2026
Table of Contents
Quick Summary
Meat By-Products Non-rendered parts from slaughtered animals—organs, blood, bone, fatty tissue. Excludes meat, hide, hooves, hair, horns.
What It Is
Meat by-products are the non-rendered, clean parts of slaughtered mammals other than meat (muscle tissue). According to AAFCO, meat by-products include organs, blood, bone, stomach, intestines (freed of their contents), and fatty tissue, but specifically exclude meat, hide, hair, horns, teeth, and hooves. This means meat by-products can include highly nutritious organ meats (liver, heart, kidney, spleen, lungs) as well as less desirable parts (intestines, stomach lining, blood). The term 'by-products' has developed a negative reputation among consumers, who often assume these are 'waste' or low-quality ingredients. The reality is more nuanced: organ meats are nutritionally dense and represent premium ingredients when sourced from quality animals and properly handled. However, the vague 'meat by-products' label provides no transparency about which organs or tissues are included, their source animals, or their quality. This lack of specificity is the primary concern - not that byproducts are inherently bad, but that consumers have no way to judge quality, and manufacturers could include anything AAFCO-compliant from premium organs to lowest-grade acceptable tissue.
Compare to Similar Ingredients
- vs. beef liver: Beef liver is a specific, named organ meat - consumers know exactly what they're getting. Meat by-products could include liver along with numerous other organs and tissues, without specifying which ones, their proportions, or quality. Named organ meats (like beef liver) signal transparency and quality, while generic 'meat by-products' suggests cost-cutting and opacity. Both can be nutritious, but beef liver provides guaranteed quality and composition while meat by-products are a mystery blend.
- vs. chicken meal: Chicken meal is rendered, concentrated protein from specific chicken parts (flesh, skin, sometimes bone) with clearly defined ingredient. Meat by-products are non-rendered internal organs and tissues from unspecified mammal sources ('meat' could be beef, pork, lamb, or mixed). Chicken meal has consistent protein concentration (60-65%) and quality standards; meat by-products vary wildly in composition and nutritional value depending on what organs/tissues are included. Meal is processed for stability; by-products are less processed but also less shelf-stable.
- vs. poultry by product meal: Both are by-product ingredients lacking transparency. Meat by-products come from mammals and are non-rendered (fresh/frozen); poultry by-product meal comes from birds and is rendered (cooked, dried, ground). The rendering process in poultry by-product meal provides shelf stability and concentrated protein, while non-rendered meat by-products retain more moisture and natural structure. Neither provides adequate transparency about specific organs or quality, making both problematic from a consumer information standpoint.
Why It's Used in Dog Products
Meat by-products appear in dog food primarily for economic reasons - they're significantly cheaper than named muscle meats or specific organ meats. When animals are slaughtered for human consumption, internal organs represent valuable protein and nutrients but aren't typically sold in mainstream U.S. markets (though organs are valued in many other cultures). Pet food provides a market for these parts, reducing waste and providing affordable protein sources. From a nutritional standpoint, organs like liver, heart, and kidney are actually more nutrient-dense than muscle meat, containing higher concentrations of vitamins, minerals, and beneficial compounds. However, manufacturers use the generic 'meat by-products' term rather than listing specific organs for several reasons: (1) flexibility in formulation - they can use whatever organs are available and cheapest at any given time; (2) cost savings - bulk purchasing of mixed by-products is cheaper than sourcing specific named organs; (3) avoiding consumer scrutiny - many consumers reject foods with specific organ names despite their nutritional value. The term appears primarily in budget and mid-tier commercial foods, rarely in premium brands that market transparency and specific ingredient sourcing.
Nutritional Profile
Quality Considerations
Quality varies from potentially excellent to questionable, with no transparency to distinguish. At best, meat by-products include premium organs (liver, heart, kidney) from healthy, well-raised animals, properly handled and fresh. This represents genuine nutritional value rivaling or exceeding muscle meat. At worst, meat by-products include lowest-grade acceptable tissues (stomach lining, fatty scraps, blood) from unknown sources, possibly older or diseased animals rejected for human consumption, with questionable handling. Most likely, reality falls somewhere in between with mixed quality depending on the manufacturer's standards and purchasing practices. Premium brands typically avoid generic 'meat by-products' entirely, choosing instead to list specific organs ('beef liver,' 'chicken heart') that signal transparency and quality control. Budget brands use meat by-products to achieve low prices, prioritizing cost over transparency. The lack of specificity is the red flag - if the organs included were high-quality, why not name them? The vague term suggests the manufacturer wants flexibility to use whatever is cheapest, which doesn't inspire confidence.
Red Flags
- Generic 'meat by-products' without any species specification (could be any mammal)
- Meat by-products listed as first or second ingredient (suggesting heavy reliance rather than supplementation)
- No other named organ meats in formula (if liver is good enough to include, why not name it?)
- Very cheap dog food with meat by-products as primary protein source
- Manufacturer unable or unwilling to disclose which organs are typically included
- No other quality indicators (no human-grade claims, no sourcing transparency, no USDA organic)
Green Flags
- Meat by-products used minimally, with named proteins and organs as primary ingredients
- Brand provides transparency about typical organ composition when asked
- USDA organic certification (ensures source animal quality regardless of vague naming)
- Company reputation for quality control and testing
- Meat by-products from single specified species: 'beef by-products' or 'pork by-products' (slightly better than generic 'meat')
Meat by-products include organ meats that can be highly nutritious (liver, heart, kidney) but suffer from complete lack of transparency about specific composition and quality. Without knowing which organs or tissues are included, their proportions, or source animal quality, consumers cannot assess nutritional value or consistency. Premium brands use named ingredients instead.
Potential Concerns
The primary concern is lack of transparency and quality assurance. 'Meat by-products' could be nutritious organs from healthy animals or lowest-grade tissues from questionable sources - consumers have no way to know. This opacity suggests manufacturers want flexibility to use whatever is cheapest, which doesn't inspire confidence. Second, inconsistency - the nutritional value and ingredient composition can vary dramatically between batches without consumers noticing. Third, potential for low-quality sourcing - while organs themselves are nutritious, by-products may come from animals deemed unfit for human consumption (diseased, dying, dead, or disabled - the '4-D' animals, though USDA regulations prohibit the worst cases). Fourth, digestive tolerability - some dogs develop digestive upset from meat by-products, possibly due to fatty tissue, unfamiliar proteins, or quality issues. Fifth, contamination risk - organs like liver and kidney filter toxins and may accumulate environmental contaminants if animals aren't raised properly. Sixth, the stigma itself - even if nutritionally adequate, using meat by-products signals a focus on cost over transparency, which often correlates with other corners being cut in formulation and quality control. Finally, the missed opportunity - organs are nutritious and deserve a place in dog diets, but hiding them under vague terminology perpetuates negative perceptions and prevents consumers from making informed choices.
Contraindications
- Dogs with sensitive stomachs may react poorly to the variability and unknown composition
- Dogs with specific protein allergies have no way to know if their allergen is included
- Dogs requiring consistent, predictable nutrition for medical conditions shouldn't rely on variable ingredients
Life Stage Considerations: Meat by-products can appear in foods for all life stages, though their unpredictable composition and quality make them suboptimal for any stage. Puppies need consistent, high-quality nutrition for growth - the variability in by-products is concerning. Adults might tolerate the inconsistency better but still deserve transparency. Senior dogs often have more sensitive digestion and benefit from consistent, easily digestible proteins rather than mystery blends. Pregnant and nursing dogs have elevated nutritional needs better met by named, quality-assured ingredients.
Scientific Evidence
Limited specific research exists on 'meat by-products' as a category because it's not a defined ingredient with consistent composition. Research on organ meats individually shows they're highly nutritious. The concern with meat by-products is lack of transparency and quality assurance, not inherent nutritional inadequacy.
Key Research Findings
- Organ meats like liver, heart, and kidney contain higher concentrations of vitamins, minerals, and beneficial compounds compared to muscle meat (Nutritional composition studies of organ meats) [Source]
- AAFCO definitions permit wide variation in meat by-product composition, making nutritional assessment and quality control difficult (AAFCO Official Publication) [Source]
Evidence Level: Limited research on 'meat by-products' specifically due to variable composition. Strong evidence that organ meats are nutritious, but unknowable which organs or proportions are in any given by-product ingredient.
How to Spot on Labels
Reading ingredient labels can be confusing. Here's how to identify and evaluate this ingredient:
What to Look For
- Look for 'Meat By-Products' or 'Meat By-Product' in ingredient list
- May appear as first ingredient in very budget foods, or toward middle in mid-tier foods
- Species-specific versions slightly better: 'Beef By-Products' or 'Pork By-Products'
- Absence of named organ meats alongside by-products is concerning (why not name them?)
Alternative Names
This ingredient may also appear as:
- Meat by-products (generic mammals)
- Beef by-products (specific to cattle)
- Pork by-products (specific to pigs)
- Lamb by-products (specific to sheep)
Typical Position: In budget foods, meat by-products often appear as first or second ingredient, indicating heavy reliance. In mid-tier foods, may appear in positions 3-7 as supplemental protein. Premium foods typically avoid meat by-products entirely, using named proteins and specific organs instead.
Here's the nuance: organ meats like liver and heart are more nutritious than muscle meat - if meat by-products consisted primarily of these premium organs from quality animals, they'd be excellent ingredients. The problem is you'll never know because manufacturers hide behind vague terminology. This opacity signals cost-cutting over transparency. If the organs included were consistently high-quality, brands would name them specifically ('beef liver') for marketing advantage. The generic term means they want flexibility to use whatever is cheapest. We recommend avoiding meat by-products not because they're inherently bad, but because lack of transparency prevents informed choices and typically correlates with overall lower quality standards.
Frequently Asked Questions
Are meat by-products really that bad?
The honest answer is: it depends on which organs and tissues are included, but you'll never know because manufacturers don't specify. The term 'meat by-products' INCLUDES organ meats like liver, heart, and kidney which are exceptionally nutritious - in many ways superior to muscle meat. If meat by-products consisted primarily of these premium organs from healthy animals, they'd be excellent ingredients. The problem is complete lack of transparency. The vague term allows manufacturers to use whatever is cheapest - could be premium liver one batch, stomach lining and fatty scraps the next. You have no way to verify quality, consistency, or specific composition. This opacity is the red flag. Premium brands that use organ meats list them specifically ('beef liver,' 'chicken heart') to demonstrate transparency and quality. If the organs included were high-quality, manufacturers would name them to boost marketing appeal. The generic term suggests they want flexibility to use whatever is available and cheapest, which doesn't inspire confidence.
What's actually in meat by-products?
According to AAFCO, meat by-products include non-rendered organs and parts from slaughtered mammals: liver, heart, kidney, spleen, lungs, stomach, intestines (emptied), blood, bone, and fatty tissue. They specifically exclude muscle meat, hide, hair, horns, teeth, and hooves. In theory, this could be nutritious organs. In practice, manufacturers aren't required to specify which parts or in what proportions. One food might be mostly liver and heart; another might be mostly stomach lining and intestinal tissue. The ratio likely varies batch-to-batch based on what's cheapest. You're getting some combination of organs and tissues, but exactly which ones and their quality remain unknown. If you want to know the typical composition in a specific food, contact the manufacturer directly - though most won't provide detailed answers, which tells you something about their priorities.
Why don't manufacturers specify which organs are in by-products?
Two main reasons: flexibility and marketing. First, flexibility - by using the generic 'meat by-products' term, manufacturers can buy whatever organs and tissues are cheapest at any given time without reformulating. If liver becomes expensive one month, they can use more kidney or spleen instead without changing the label. This reduces costs and logistical complexity. Second, marketing concerns - many consumers reject foods listing specific organs like 'liver' or 'spleen' despite their nutritional value, due to unfamiliarity or squeamishness. The vague 'meat by-products' term avoids triggering this rejection. However, this logic doesn't hold up - premium brands successfully market organ meats by naming them specifically, appealing to informed consumers who understand nutritional value. The real reason most brands use generic terms is that naming specific organs would require quality control and consistency, which costs more. If the organs included were consistently high-quality, manufacturers would name them for marketing advantage.
Should I avoid meat by-products entirely?
We recommend choosing foods with named protein sources (specific meats and organs) over generic 'meat by-products' whenever possible. The lack of transparency makes it impossible to assess quality, and transparency generally correlates with overall brand quality standards. That said, if budget constraints limit options and you're choosing between foods with meat by-products versus plant-heavy formulas with minimal animal protein, the by-products may be the better choice - they at least provide animal-based protein and nutrients, even if composition is unclear. The bigger issue is what the use of generic by-products signals: a manufacturer prioritizing cost over transparency, which often correlates with other corners being cut. Better approach: look for foods listing specific proteins ('chicken,' 'beef,' 'chicken meal') and named organ meats ('beef liver,' 'chicken heart'). If organs are good enough to include, they should be good enough to name. Budget brands exist that use named proteins - you don't need to pay premium prices to avoid vague ingredient terms.
Are meat by-products safe?
Yes, meat by-products are generally safe in the sense that they must meet AAFCO ingredient definitions and basic safety standards. USDA regulations prohibit the use of '4-D' animals (dead, dying, diseased, or disabled) in pet food ingredients, though enforcement and interpretation vary. The organs and tissues included in by-products aren't inherently unsafe - liver, heart, and kidney are foods humans eat in many cultures. However, 'safe' and 'quality' are different standards. Meat by-products are unlikely to harm your dog acutely, but the unknown composition and potential variability make them a poor choice for optimal nutrition. Additionally, organs like liver and kidney filter toxins and may accumulate contaminants if source animals weren't raised properly. Without transparency about sourcing and quality control, you're accepting that risk. Safe? Probably. Optimal? Definitely not. Transparent and trustworthy? No.
What's the difference between by-products and by-product meal?
The key difference is rendering (cooking and drying). Meat by-products are non-rendered - fresh or frozen organs and tissues with their natural moisture content (70%+ water). By-product meal (like 'poultry by-product meal') is rendered - cooked, dried, and ground into a concentrated powder with minimal moisture (10% water) and concentrated protein (60%+). Rendering provides shelf stability and concentrated nutrition per pound. Non-rendered by-products provide moisture and may retain some heat-sensitive nutrients but contribute less protein after cooking/extrusion. Both suffer from the same transparency problem - you don't know which specific organs or tissues are included or their quality. However, by-product meal's rendering process provides some standardization of composition and protein concentration, while non-rendered by-products are more variable. Neither is ideal, but if choosing between them, by-product meal at least offers more consistent protein contribution despite the opacity.
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