Alexander’s army of 65,000 Macedonians was also accompanied by 1300 baggage animals and 6100 cavalry horses, according to Engel. The estimation of this exact number of animals would fluctuate due to the provisions being carried, availability of animals, as well as those lost to sickness and exhaustion. Horses, mules, and camels were the main types of pack animals included in Alexander’s baggage train.
In addition to food and provisions, some pack animals were used for carrying non-comestible supplies like tents, hammocks, firewood, medical supplies, and treasure. A few horse or mule-drawn carts were designated to carry siege weapons, act as the army ambulance, or sometimes carry women and children. These were limited due to their tendency to break down and their cumbersome nature over rough terrain. Carts were additionally restricted because of the inefficient throat and girth harness, which was placed directly over the animal’s windpipe: the harder the horse pulled, the more it choked him. (Engel)
Horses and mules are basically the same as far as rations and carrying capacity; both require an average of ten pounds of grain rations, ten pounds of grazing fodder, and eight gallons of water per day (Engel 18). A horse or mule can carry two-hundred pounds and each animal is capable of pulling a load directionally proportional to its body weight. The animals can bear the load, whether from pack or rider, for about five to seven consecutive days. After that, they will need to rest and have time – at least sixteen hours a day – for grazing to stay in good condition (Sidnell 85). Being a military campaign, conditions were not particularly ideal for the animal. Many horses died from exhaustion and/or malnutrition because the speed of the march prevented them from grazing, even though there was plenty of grain supply (Engel 81). Under these types of harsh conditions, common equine health issues may have also included wounds, poor body condition, respiratory diseases, parasites, dental problems, and lameness (Burn et al.)
Unfortunately, sick, injured, or exhausted horses were an encumbrance to the army and had to be left behind. Worse things could happen to a pack animal, namely being engulfed by sand, washed away by monsoons, or eaten by hungry soldiers (Arrian 6.24.4-6, 6.25.1-3, 6.25.4-5). Alexander turned a blind eye on this sort of ravenous activity, especially during desperate times. It made sense for the soldiers to eat the animals – after all, the average camel carcass provides 900-1400 pounds of meat (Wikipedia Contributors).
The introduction of the camel may have occurred after the Battle of Issus where Darius’ baggage train, which included camels, was captured by Alexander’s army. The benefits of using camels as pack animals in arid climates is obvious; camels are genetically developed to withstand temperatures and conditions that would kill most other animals (Wikipedia). A camel can also carry at least one hundred pounds more than the typical horse or mule (Engel 14). The largest disadvantage of using camels is that they require more water – ten gallons per day on average (Engel 18).
Besides camels, Alexander’s entourage even included elephants at times, some of which were captured from enemy baggage trains or rounded up from abandoned settlements (Arrian 3.15.4,4.30.7). When Alexander arrived at the Indus River, he was presented with thirty elephants in addition to the two ships, two hundred silver talents, three thousand sacrificial oxen, and ten thousand head of cattle (Arrian 5.3.5). Alexander’s horse, Bucephalus, was bred from famous Thessalian strain and cost thirteen talents – enough money for a Greek laborer to live on for a hundred years (Sidnell 85).

A dark brown Andalusian horse. Andalusians and other Spanish breeds are believed to be descended from the now extinct Nisaean horse - the most beautiful and valuable breed in antiquity.

One of Emperor Taizong's horses from Zhaoling - likely to have Ferghana bloodlines. Tang Dynasty (c.650). University of Pennsylvania Museum of Archaeology and Anthropology.
Works Cited
Arrianus, Lucius Flavius. The Landmark Arrian: the Campaigns of Alexander. New York: Pantheon Books, 2010. Print
Sidnell, Philip. Warhorse: Cavalry in Ancient Warfare. New York: Continuum Books US, 2006. Print
Engels, Donald W. Alexander the Great and Logistics of the Macedonian Army. Berkeley: University of California Press, 1978. Print.
Burn, Charlotte C., Tania L. Dennison, and Helen R. Whay. “Relationships between behaviour and health in working horses, donkeys, and mules in developing countries.” Applied Animal Behaviour Science 126, 3 (2010): 109-118. Web. 8 Feb. 2012
Wikipedia contributors. “Nisean horse.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 12 Dec. 2011. Web. 9 Feb. 2012.
Wikipedia contributors. “Camel.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia. Web. 8 Feb. 2012.