I've done a bunch of them gutless and for sure it saves a lot of work.
However......I'm convinced that boning a freshly killed animal can make them tougher. If the muscles are cut before they go into rigor mortis, the fibers will shrink which makes them tougher. Cooling meat too fast will do it, too, in a process known as cold shortening. This is a problem if you shoot one when it's really cold and immediately skin it.
It's possible to remove the 4 quarters with only minimal cutting of muscles. Removing the meat from the bone, though, and taking out the loins will allow the muscles to contract while still warm.
Over the years, the most memorably tough animals I've shot have all been done gutless. In recent years, I've been using llamas to pack meat. I field dress the deceased and skin depending on how hot or cold the weather is. By the time I get back with the llamas, it's usually ready to bone. If I shoot it in the evening. I'll let it lie and bone it the next morning.
Here's a technical rundown of what's going on:
13 Rigor & Cold shortening
13.1 Introduction
Rigor mortis is a loss of muscle extensibility marking the conversion of muscle to meat. In other words, living muscles can be stretched and they return to their resting length when released. Meat cannot be stretched and has very little elasticity. A strong attempt to stretch a length of meat will merely rip it.
Just before a muscle sets in rigor mortis, it may attempt to shorten. Refrigeration increases the shortening - giving rise to the name cold shortening. But even cold shortening is weak relative to contraction of a living muscle. A muscle will only contract if there are no skeletal restraints. What does this mean? Consider a beef animal walking into the abattoir on all four legs - a leg at each corner of the body. We slaughter it and suspend it by its hindlimbs. The muscles ventral to the vertebral column are stretched and cannot shorten before rigor mortis develops. But the muscles dorsal to the vertebral column have no skeletal restraints and are free to contract - either from the very weak shortening just before rigor develops, or the slightly stronger cold shortening caused by refrigeration.
Why is this important? Because shortening decreases sarcomere length and increases the overlap of thick and thin myofilaments. This increases the toughness of the meat. Nobody likes tough meat. It is important to understand how to minimize cold-shortening.
The key point to grasp is - the sarcomere can only shorten if it still has ATP and has not yet developed rigor mortis. An exhausted muscle has minimal glycogen, therefore minimal post-mortem re-synthesis of ATP, therefore it develops rigor mortis early. Once rigor has developed - the muscle cannot shorten. We are safe. We cannot make meat tough by rapid refrigeration.
Cold-shortening is a very complex phenomenon. The most likely cause is the effect of low temperature on the sarcoplasmic reticulum. The sarcoplasmic reticulum works hard using ATP to sequester calcium ions. When it is cooled - it begins to fail. Calcium ions remain in the cytosol. The muscle slowly contracts. Cold shortening is more severe in red muscles than in white muscles because red muscles have a weak sarcoplasmic reticulum.
13.2 Rigor mortis
The conversion of muscles to meat is completed when muscles have depleted their energy reserves or have lost the ability to utilize remaining reserves. In living muscles at rest, an ATP molecule binds to each myosin molecule head and in this condition the myosin head is said to be "charged". In resting muscle, further developments between the actin and myosin of thin and thick myofilaments are prevented by the intrusion of tropomyosin molecules. Contraction in living muscle is initiated by the release of calcium ions from the sarcoplasmic reticulum, and followed by the removal of the tropomyosin intrusion. As a muscle contracts, charged myosin molecules heads attach to actin molecules, ATP is split to ADP with a release of energy, and the myosin molecule head swivels to cause filament sliding. The myosin molecule head, which is still attached to its site on the actin, can only detach itself if a new ATP molecule is available to be be bound. When muscle is converted to meat, myosin molecule heads remain locked to actin and even passive filament sliding is impossible.
