Oxytocin ?

[Dale L]

How long after birth is too long for oxytocin to be effective for milk let down? Have heard it needs to be within 24 hrs. Is this true?

 

[Lucky_P]

Oxytocin is always involved in 'milk let-down', throughout a cow's lactation. That's one of the reasons for udder-prep activities on dairy cattle - and why that calf butts the dam's udder.
It will not, as some seem to think, 'bring a cow into her milk'. If she's not got any, oxytocin's not gonna magically create it.

 

[talltimber]

Oxytocin is always involved in 'milk let-down', throughout a cow's lactation. That's one of the reasons for udder-prep activities on dairy cattle - and why that calf butts the dam's udder.
It will not, as some seem to think, 'bring a cow into her milk'. If she's not got any, oxytocin's not gonna magically create it.

I feel like I've learned so much, but yet still so very ignorant...

 

[Lucky_P]

tt,
Calf-butting, and udder prep - washing/cleaning/drying udders in preparation of applying the milking machine - or hand-milking - all serve to cause the cow's pituitary gland to release oxytocin, resulting in 'milk let-down'.

 

[dun]

I had wondered why some dairys gave it at every milking to the slow let down cows.

 

[Lucky_P]

Never spent much time milking...and can't swear that it's not helpful with some individual animals, dun...but not necessary for the vast majority of them.
Visual/auditory clues(stuff clanking around in the milking parlor, the milkers pulsing on/off, etc.) probably also get those acclimated cows started releasing oxytocin even before they come into the parlor. Kinda like Pavlov's dog...

 

[regolith]

I had wondered why some dairys gave it at every milking to the slow let down cows.

One of my heifers last spring was a slow milker that had to have the cluster held up during milking, though her udder didn't seem too badly shaped.
I culled her something like a month after she calved, but it wasn't till the day we herd tested that I was standing holding her milking machine on and watching the milk dribbling in a stop/start pattern through the meter that I realised she wasn't a slow milker - she had a letdown problem and I might have fixed her with oxytocin if I'd realised. I just heard recently that several more of her sire's daughters also have let-down issues.
But I'd still cull her before injecting her with oxytocin every milking. IME the ones that need it aren't worth persevering with anyway, they'll dry themselves off with or without the injections.

Oxytocin used to contract the cow's uterus down after calving is a whole different thing, always gave it straight after pulling the calf.