when to breed dairy heifer

[jersey girl]

I have a jersey heifer and I wanted to know at what age should I breed her. I have had several people tell me to wait untill she is 19 to 20 months old but that would make her have her calf in the heat of the summer. Does it matter if I wait untill she is older or if I have her bred when she is 15 to 18 months old?
Thank you for the help.

[Rhodie]

[quote=jersey girl]I have a jersey heifer and I wanted to know at what age should I breed her. I have had several people tell me to wait untill she is 19 to 20 months old but that would make her have her calf in the heat of the summer. Does it matter if I wait untill she is older or if I have her bred when she is 15 to 18 months old?
Thank you for the help.[/QUOTE
We breed at 15 months in the Jersey herd, to calve at 2 years.

[nauman]

^ according to my point of view, it is better idea to examine her weight. You must know the adult weight of an adult jersy cow, so when its heifer reaches at the weight of 66% of its adult body weight, just breed her either her age is 12-15 months, or 18-20months.
To attain the required body weight in time, you need to focus on her feed and nutrition; and all other husbadry practices.

[From field to fork]

[/QUOTE
We breed at 15 months in the Jersey herd, to calve at 2 years.[/quote]

Do you take any account of the time of year she will calve. i.e. during the winter. Or do you keep strictly to the 15 months?