Yaks

 Yaks are native to the Himalayas and China. The raising of a yak is very similar to cattle, as both are in the Bovidae family. Yaks have a scientific name of Bos grunniens. A cross between a cow and a yak is called a yattle. Yaks are milk and meat animals. Yak has pink milk. An adult pack yak can carry up to 130# at 15 miles a day. A castrated male yak is called a yak. An intact male (bull) is called a boa while a female (cow) is called a dri. The white color in some domestic yak is not seen in the wild; most are brown or black in color. For health certificates and other similar issues, we will call them bulls, cows, calves and yaks; this is to keep things simple and understandable for those involved with such animals and regulations. For regulatory purposes yaks are treated the same as cattle. The tuberculosis, Brucellosis and other tests required is the same for yaks traveling interstate. We do not vaccinate routinely Yaks for Brucellosis. We are in a Brucellosis free state. The other routine vaccines, dewormers and treatments commonly recommended for cattle in our area are the same for yaks. All the diseases a cow can get, a yak also is capable of obtaining. Being an animal able to live above tree line, the “high mountain disease” heart failure is not a problem. The red blood cells of yaks are almost half the size of a cow’s cells, which is an advantage at high altitude. With the long hair and fewer sweat cells than a cow, an open shed is recommended for shelter from the heat. Yak can survive naturally in weather to 40 degrees below zero.

            An average adult bull can weigh up to 1200#, while a cow can be 900#. The weight and height of domestic yak can vary, as with cattle breeds.   In China, the wild variety boa can be over 6’ and 2000#, with the average wild dri less than half this size. The average a female will weigh 1/3 to 1/2 of the male’s weight. All yak seen commercially and in zoos are of the domesticated variety. An age of 20-25 years can be obtained, although the actual productive age to be expected is less than 15 years. If yaks are pastured with cattle (Bos taurus), her male offspring will be a sterile, yet the yak-cattle females can be fertile. We feel these crossbred “dzos or dzopkyos” should not be bred. Dzos do make good pack animals. We do not recommend yak to be bred before 2 years of age. It takes up to 6-8 years for a yak in the wild to be full-grown. Naturally they breed in the fall and early winter, and calve about 9 months later in the spring (260 days gestation).      

            All newborn livestock require colostrum, the first milk in order to be healthy. This colostrum contains antibodies that fight infection. The calf only absorbs the antibodies within the first 12-18 hours of life. A newborn animal’s immune system is not capable of fighting infections for 4-6 weeks and colostrum is the main infection defense for a newborn calf. This is why we do not normally recommend any vaccinations for most newborn animals until they are 6?8 weeks old. Before this time the calf is not capable of responding very well to the vaccine. In a newborn animal the vaccine might tie up the antibodies in the colostrum leaving the calf defenseless. After 24-48 hours of being born these antibodies are not absorbed and instead are digested for food by the calf’s intestinal system. A vitamin A & D injection, a source of good bacteria orally, and a tamed iodine or chlorahexadine applied to the navel is also advised for a newborn yak calf. An antibiotic injection may be indicated in some patients. It is very important to record the date of birth of all animals involved with food. We have a simple system for individual record if you do not have any such system. If using yak milk, it is generally collected for consumption after the 10th day since calving.

            Vaccination of the yak calf starts at 3-4 months of age, earlier if there is a disease outbreak. IBR, BVD, PI3, Lepto 5, BRSV (syncytial virus) & 7-way clostridium make up the usual vaccination program. Histophilus (Haemophilus), Campylobacter (Vibrio), E. Coli, pink eye, Staph., anthrax, Mannheimia (Pasteurella) and others may also be needed. We can help you with your individual herd’s requirements. Vaccine boosters are recommended when the calf is 6 month of age, at which time deworming is also administered. The use of periodic fecal exam tests in the calves, and again with the adults, is recommended. Yaks can be weaned at this time, or preferably later when they are up to a year of age.  

            For the permanent herd we advise yearly vaccinations, as we are usually vaccinating for calf colostrum quality as much or more than just disease prevention. We recommend only killed vaccines be used on Yaks, routinely, as it is possible some modified live vaccines (MLV) can cause problems in animals not on the label. MLV vaccines also can cause abortions. Because cattle and yaks are both in the Bovidae family, many similar products can be used on the average. Almost all products used in Yak medicine are extra-label use of a product. Please ask for our handout on extra-label drugs if you are unsure of what it means. Deworming and external parasite control is also needed 1-6x a year, depending upon the herd and environment. We do not recommend yaks, or any cattle with any Bos indicus blood, to use products which have a label not to use on “cattle of India origin”. These cattle, and possibly yaks, cannot tolerate some organophosphate products. Between June and November you can have reactions from the migrating grub parasite to products labeled for cattle grubs. It is important to control the gnat population which can transmit epizootic hemorrhagic disease (EHD); we have other handouts on these two issues. Calves can be castrated or banded anytime the testicles can be felt, which can be as early as a couple weeks of age. The typical castration age is 4-8 months. At this age we also recommend testing all calves for Bovine Virus Diarrhea-Persistently Infected animals (BVD-PI), or earlier if you are working the calves as a group. After a year of age the male calves can possibly start breeding the female calves. To prevent dystocia we recommend not breeding before an animal is at least 65% of her adult weight. If nutrition is poor, the cow may only give birth once every 2-3 years, instead of the average 1-2 years; two years is average in China‘s domestic herds.

            In order to keep accurate records we advise identifying the calves soon after birth. Many record systems are available for recording the calf’s parents, its birth date, weights, treatments, etc. Being hairy animals it is a good idea with the farm tag to tag the left ear of female cattle and the right ear of male cattle. We recommend using the official USDA tags for identification, such as the RFID tags which have a wide flap for a farm tag number. It is a good idea to tag and castrate calves at a young age. Yaks are very agile, and a chute or head catch/close down gate is needed. These chutes need to be secure and not a show type chute for if/when you need to treat an animal. Look for a very wide squeeze chute. If yaks are being pastured with other species of animals we recommend that they are to be dehorned at a very young age (2 months old or less); with long-horned cattle there is the same safety concern for other animals. Yaks do not moo, but instead grunt. If hardware is a concern we advise giving magnets at around 10 months of age to all yaks.

            The feeding management of herbivores depends upon the forage available locally and/or on the farm. As with most herbivores we recommend feeding more hay and less grain. In the wild the yaks have to survive on eating grass and lichens. In yaks grain is not needed, and should be fed at a minimum. If you observe individual animals not eating during feeding you will catch a lot of sick animals early that normally would be found dead. Anytime there is a sale or transfer of livestock, the Colorado brand inspector needs to be contacted and then a bill of sale needs to be made. All premises where livestock are kept are required to be registered with the USDA: www.aphis.usda.gov/

The Staff at the Nelson Road Veterinary Clinic

303-678-VETS(8387)