(no subject)
>>> The first time dairy cows are impregnated is at 13-15 months of age, so that they give birth and first start producing milk at about 20 - 24 months of age (http://animsci.agrenv.mcgill.ca/courses/450/topics/6.pdf ). From then on, the most common standard is that all cows are impregnated 70 to 90 days after each time they give birth with the intent of having them give birth every 12 months (the calving interval) http://pubs.caes.uga.edu/caespubs/pubcd/B1210.htm see table 1. Factory “Production” rates per cow during peak lactation are targeted for 50-60kg of milk per day at which rates cows reduce productivity faster and are killed for meat sooner. There are debates in the literature about the productivity merits of a Calving Interval of 18 months http://jds.fass.org/cgi/content/abstract/14/4/294 , but it isn’t considered good practice.
>>> The 1 year Calving interval is timed with the cow’s “lactation curve”. “A lactation curve depicts a cow's milk yield after colostrum to drying-of”, about 300 days (http://animsci.agrenv.mcgill.ca/courses/450/topics/11.pdf). The only way to re-start lactation curve is by impregnating the cow. They make sure that cows which are drying off are already pregnant with the next calf, at which time they are called “transition cows” http://animsci.agrenv.mcgill.ca/courses/450/topics/7.pdf
>>> When the calf is born, it is to be taken from the cow on the same day (within 12hrs http://animsci.agrenv.mcgill.ca/courses/450/topics/5.pdf). There are two types of housing for calves that aren’t going to be used to produce milk:
> kept for 14 to 17 days in 2 ft wide ‘veal crates’. These crates are designed to restrict movement (e.g. no turning around) so as to minimise bruising risk to meat etc. http://en.wikipedia.org/wiki/Image:Calf_stalls.jpg Australian veal crates (or "individual housing" as the Code of Practice calls them) have to allow 2 m^2 (1m x 2m or equivalent) per calf.
> or group housing (very rare) http://en.wikipedia.org/wiki/Image:Veal_group.jpg
i wanted to keep this somewhere for future reference, so i thought here is great. vegans - if anyone asks for links about milk, here they are. its unbiased, non veg sources without emotive language.