Limousin bull mating with suckler cow which on heat Cumbria

 

The gestation period for a cow is about nine months long. A newborn calf's size can vary among breeds, but a typical calf weighs 25 to 45 kg (55 to 99 lb). Adult size and weight vary significantly among breeds and sex. Steers are generally slaughtered before reaching 750 kg (1,650 lb). Breeding stock may be allowed a longer lifespan, occasionally living as long as 25 years. The oldest recorded cow, Big Bertha, died at the age of 48 in 1993.

On farms it is very common to use artificial insemination (AI), a medically assisted reproduction technique consisting of the artificial deposition of semen in the female's genital tract. It is used in cases where the spermatozoa can not reach the fallopian tubes or simply by choice of the owner of the animal. It consists of transferring, to the uterine cavity, spermatozoa previously collected and processed, with the selection of morphologically more normal and mobile spermatozoa.

A cow's udder contains two pairs of mammary glands, (commonly referred to as teats ) creating four "quarters". The front ones are referred to as fore quarters and the rear ones rear quarters.

Synchronization of cattle ovulation to benefit dairy farming may be accomplished via induced ovulation techniques.

The secondary sex ratio – the ratio of male to female offspring at birth – is approximately 52:48, although it may be influenced by environmental and other factors.Bulls become fertile at about seven months of age. Their fertility is closely related to the size of their testicles, and one simple test of fertility is to measure the circumference of the scrotum: a young bull is likely to be fertile once this reaches 28 centimetres (11 in); that of a fully adult bull may be over 40 centimetres (16 in).

A bull has a fibro-elastic penis. Given the small amount of erectile tissue, there is little enlargement after erection. The penis is quite rigid when non-erect, and becomes even more rigid during erection. Protrusion is not affected much by erection, but more by relaxation of the retractor penis muscle and straightening of the sigmoid flexure.

Semi-wild Highland cattle heifers first give birth at 2 or 3 years of age, and the timing of birth is synchronized with increases in natural food quality. Average calving interval is 391 days, and calving mortality within the first year of life is 5%.