Most dairy heifers should be at least 15 months of age before they can be bred.
Only once a year.
yes
For the small-time producer, yes, but as a conventional beef animal, no definitely not. Brown Swiss are bred to be dairy cattle, or to produce milk, not to produce beef. However, that's not to say that they cannot be raised as beefers: Brown Swiss steers tend to fatten up and finish better than Jerseys, for one, and even Holsteins. But they're still dairy cattle regardless.
The breeding season of dairy cattle is year-round, or they can be bred any time of the year, provided they have 2 to 3 months after calving to come back into their normal cycle. From their first heat, they have an estrous period of ~21 days until they are bred again.
Holstein heifers can be bred at around 15 months of age. Bulls can be used for breeding by the time they reach around 12 months of age.
Yes, that's what happens when you select certain pigs to be more lean and grow more muscle on their frames in a shorter time period: same with broiler chickens or beef cattle. With layers, producers are selecting for hens that will produce a large number of eggs within their "allotted" life-time. Similar thing goes for dairy cows selected to produce milk.
Dairy cattle require more higher nutritive feeds than beef cattle do, and so need to be raised in an area where these higher nutritive feeds can be raised and fed to them. Dairy farms are located on or near the "corn belt" or an area of land on the North American continent where crops can grow and have high quantity and quality yields. Pastures in this area where some dairy farms allow their cows and heifers to graze during the summer months (or those months where grass grows the lushest) also need to have this high quantity and quality of grasses. The area also needs to be level and flat enough that barns and silos can be built and that are easily accessible to farm equipment used on the dairy farm. Beef cattle, on the other hand, are raised in areas where they are on pasture all the time and do not require much human input. Beef cattle can be raised in areas where dairy cattle are raised, or in much more rougher terrain like down in the desert of southern California, Nevada, Arizona, New Mexico and West Texas. Beef cows have a much lower nutritive requirement to thrive and feed a calf than dairy cows do, and so are much more flexible where they can be raised.
Either and both can be just as bad as the other if they're fed in a 100% ration for a long period of time. As supplements to a forage ration to animals that need it, it's not bad at all; rather it's beneficial for the animal especially if the forage fed isn't enough to meet the animal's nutritional requirements, especially when it comes to protein and energy requirements. This is especially true with grazing dairy cattle, be it mature dairy cows or growing dairy calves (regardless of gender), less with beef cattle except for feeder/finisher cattle.
Often in those areas there are good soils and ideal topography to grow crops and hay that are highly nutritious for dairy cattle. The Great Plains, areas by the Great Lakes and by the ocean on the western side of the states are among some of the ideal places to raise dairy cattle. Additionally, increasing US state regulation has artificially moved some dairy operations to other parts of the country. For example, it is estimated that California will have to import most of its meat, dairy, and eggs from other states or countries within the next five to ten years, due to legislation which will take effect in that time period.
Reasons for using AI in dairy cattle: 1. Prevents spread of disease between bull and cow/heifer (sexually transmitted disease) 2. Safety. This is one of the biggest reasons why. Bulls are large dangerous animals that kill farmers each year. 3. Genetic improvement. Producing better offspring. 4. Synchronizing breeding Reasons for using AI in dairy cattle: 1. Prevents spread of disease between bull and cow/heifer (sexually transmitted disease) 2. Safety. This is one of the biggest reasons why. Bulls are large dangerous animals that kill farmers each year. 3. Genetic improvement. Producing better offspring. 4. Synchronizing breeding
When the female dog is ready for mating, one time is enough.
Ideally, it should only take one try for a heifer or cow to catch (become pregnant). However, you can try as many times as you want, only breeding her once per heat cycle. If she is not catching after numerous attempts, she may be infertile.