The confusion of meat

For the sake of yagna if the animal is been sacrificed its considered okay by the shastras .

here are some references

Verses for sacrifice of animal and eating

atrāpi vidhir uktaś ca munibhir māṁsa-bhakṣaṇe |

devatānāṁ pitṛṇāṁ ca bhuṅkte dattvā tu yaḥ sadā |

yathā vidhi yathā śraddhaṁ na sa duṣyati bhakṣaṇāt || 12 ||

And in this matter of animal food, this rule has been laid down by Munis:– Whoever partakes

of animal food after having first offered it duly and respectfully to the gods and the manes, is

not polluted by the act.(vyadha gita adhyayA 2)

Commentary

Manu 5:40 - 43. Herbs, trees, cattle, birds, and (other) animals that have been destroyed

for sacrifices, receive (being reborn) higher existences. On offering the honey-mixture –

madhu-parka (to a guest), at a sacrifice and at the rites in honour of the Ancestors, but on

these occasions only, may an animal be slain; that (rule) Manu has proclaimed. A twiceborn

man who, knowing the true meaning of the Veda, slays an animal for these purposes,

causes both himself and the animal to enter a most blessed state. A twice-born man of

virtuous disposition, whether he dwells in (his own) house, with a teacher, or in the forest,

must never, even in times of distress, cause an injury (to any creature) which is not

sanctioned by the Veda

cāturmāsyeṣu paśavo vadhyanta iti nityaśaḥ |

agnayo māṁsa-kāmāś ca ity api śrūyate śrutiḥ || 10 || (adhyaya 2 v.g)

For the performance of the four-monthly rites animals ought to be sacrificed daily. 'The

sacred fire is fond of animal food,' — this saying has been handed down to us.

yajñeṣu paśavo brahman vadhyante satataṁ dvijaiḥ

saṁskṛtāḥ kila mantraiś ca te 'pi svargam avāpnuvan || 11 ||

And at the Vedic sacrifices, animals are invariably killed by Brahmins, and these animals

being purged by the incantation of mantras, go to heaven.( v.g adhyaya 2)

Commentary

Rāmānuja's commentary on Brahma Sūtra-25-asuddham iti cet na śabdāt- 3-1-25

Regarding the animal killed in yajña the śruti says:– 'hiraṇya-śarīra ūrdhvah svargalokam

eti, — "attaining a golden body it (the animal) goes to heaven". 

Because it

releases the jīva from body of a lower species and makes it ascend to heaven it is

beneficial and not himsa. That action which secures an exalted status even if it involves a

little pain it is definetly considered beneficial.

The mantra which is pronounced while sacrificing the animal also declares

"na vā u etan mriyase na ripyasi devān ideṣi patibhih sugobhih; yatra santi sukrto nāpi

duṣkṛtaḥ,

"You do not die; you go to the gods on easy paths; where the virtuous go, not evil-doers."

Just as a treatment for an injury, even if involves a little pain does a lot of good so too the

animal sacrifice in yajñas benefit the jīva that inhabits the body of the animal.

similar commentary is also found in the commentary of bhagwad gita ch 2 verse 31 by Ramanuja acharya

In the Agnisomiya sacrifice no real harm is caused to the animal victim; for according to the Vedic Texts, the victim —a goat, after abandoning an inferior body, will attain a higher rebirth, with a beautiful body.

The Text pertaining to immolation declares: —

'O animal, by this (immolation) you never die, you are not destroyed. You will pass through happy paths to the realm of the gods, where the virtuous, not the sinful reach. May the god Savitur give you a suitable place.' (Yajñ, 4.6.9.46; Taitt. Br. iii 7.2)

kratau śrāddhe niyukto vā anaśnan patati dvijaḥ |

mṛgyopārjitaṁ māṁsam abhyarcya pitṛdevatāḥ ||

kṣatriyo dvādaśonaṁ tata krītvā vaiśyo’pi dharmataḥ |

dvijo jagdhvā vṛthā māṁsam abhyarcya pitṛdevatāḥ ||

A Brahmin involved in the celebration of a yajña [in which animals are slaughtered)]

becomes degraded by not taking meat (as prasādam). A Kshatriya should eat the cooked

flesh of a quarry after having offered it to the gods and pitris. A Vaishya can take meat

lawfully having bought it, after offering it to the pitris and devatas. (Vyāsa Smriti 3:57)

doṣasyaitasya vai brahman vighāte yatnavān aham |

vidhinā vihite pūrvaṁ nimittaṁ ghātako bhavet || 3 ||

But, I am always assiduous in mitigating any harm to others. The Deity is in fact the one that

takes away life, the executioner acts only as an intermediary agent.

Commentary

The example given alludes to a court of justice where a criminal is sentenced to death by

the judge. The executioner is performing a duty and has a diminished moral

accountability. The judge is the one who is actually the cause of death. Likewise Lord

Yama determines when people will die according to their karmas, the actual cause of

death is only incidental.

nimittabhūtā hi vayaṁ karmaṇo 'sya dvijottama |

yeṣāṁ hatānāṁ māṁsāni vikrīṇāmo vayaṁ dvija || 4 ||

teṣām api bhaved dharma upabhogena bhakṣaṇāt |

devatātithibhṛtyānāṁ pitṝṇāṁ pratipūjanāt || 5 ||( adhyaya 2 v.g)

And we, O good Brahmin, are only such agents in regard to karma. Those animals that are

slaughtered and whose meat I sell, also acquire indirect good karma, because (with their

flesh), gods and guests and dependents are satiated and the manes are propitiated\

It is stated in the Veda of the Vājasaneyins that the milch-cow and the draft ox are pure and can be eaten. (Vaishtha 14:46)

Animals with five claws are forbidden with the exception of the iguana, tortoise, porcupine, hedgehog, rhinoceros, and hare. (Apastamba 1:19:37 Vasishtha 14:39, Gautama 17, Manu 5:18)

If a person has unawares eaten the meat of a five-toed animal with the exception of the hare, the porcupine, the iguana, the rhinoceros and the tortoise he must fast for seven days (Vishnu Smrti 51:7, Gautama 17:27)

Firewood, water, roots, fruits, protection, meat, honey, a bed, a seat, a house, flowers, sour milk and vegetables one should never disdain to accept when they are offered. (Vishnu Smrti 57:10)

Firewood, water, grass, roots, fruits, protection, food brought unsolicited, a carriage, milk, sour milk, grain, small fish, millet, a garland, venison and vegetables spontaneously offered by a man of any caste must never be refused. (Gautama 17:3, Apastamba 1;6;18;1)

One may eat the flesh of animals killed by beasts of prey after having washed it, if no blemish is visible, and it is declared to be fit for use by the word of a brahmin. (Gautama 17:38)

Eating of flesh is forbidden during Vedic study. (Gautama 16:3)

Brahma Purāṇa 113:111. “The following can be eaten: hare, tortoise, alligator, porcupine and the fish with scales. The village pig and the cock should be avoided.”

Verses against meat eating

He who does not seek to cause the sufferings of bonds and death to living creatures, (but) desires the good of all (beings), obtains endless bliss. (Manu 5:46.)

He who does not injure any (creature), attains without an effort what he thinks of, what he undertakes, and what he fixes his mind on. (Manu 5:47.)

Meat can never be obtained without injury to living creatures, and injury to sentient beings is detrimental to (the attainment of) heavenly bliss; let him therefore shun (the use of) meat. (Manu 5:48.)

Having well considered the (disgusting) origin of flesh and the (cruelty of) fettering and slaying embodied beings, let him entirely abstain from eating flesh. (Manu 5:49.)

He who, disregarding the rule (given above), does not eat meat like a demon, becomes popular, and will not be tormented by diseases. (Manu 5:50.)

He who permits (the slaughter of an animal), he who cuts it up, he who kills it, he who buys or sells (meat), he who cooks it, he who serves it up, and he who eats it, (must all be considered as) the slayers (of the animal). (Manu 5:51.)

There is no greater sinner than that (man) who, though not worshipping the gods or the Ancestors, seeks to increase (the bulk of) his own flesh by the flesh of other (beings). (Manu 5:52.)

He who during a hundred years annually offers a horse-sacrifice, and he who entirely abstains from meat, obtain the same reward for their meritorious (conduct). (Manu 5:53.)

If he has a strong desire (for meat) he may make an animal of clarified butter or one of flour, (and eat that); but let him never seek to destroy an animal without a (lawful) reason. (Manu 5:37.)

He who injures inoffensive beings from a wish to (give) himself pleasure, never finds happiness, neither living nor dead. (Manu 5:45.)

Those two who perform a horse-sacrifice annually for an hundred years and he who does not eat meat shall both obtain the same recompense for their virtue (Vishnu Smrti 51:76)

Neither the flesh of human beings, nor the animals resembling them, nor the flesh of the cow, which is serviceable in various ways, nor the flesh of carnivorous animals, nor such meat as is tasteless, should be eaten (108) (mahanirvana tantra chapter 8) 

although the highest dharma is non voilence ( ahimsa) as per the vedas 

one should strive for minimum damage to beings as possible in word deed or thought