The use of milk progesterone to monitor reproductive function in beef suckler cows.
Milk progesterone analysis was used to monitor reproductive function in 134 autumn calving cross-bred suckler cows. Progesterone was measured in milk samples collected three times per week from around 4 week post-calving to around day 60 of pregnancy during 1st and 2nd lactation. The mean day of onset of luteal activity (OLA) was 40.7 +/- 1.1 with the distribution skewed towards a later return. Once cyclicity had been initiated the incidence of reproductive cycle problems (6.5%) was low, though animals with such problems (n = 14) exhibited a delayed interval to first service (P < 0.05), lower conception and calving rates (P < 0.001), increased services per pregnancy (P < 0.001) and a higher (P < 0.10) barren rate (14.3% versus 4.0%) compared to animals with normal cycles (n = 201). In conclusion, using milk progesterone analysis we found a relatively low incidence of reproductive cycle problems in beefxdairy suckler cows. However, while the incidence of cycle problems was low, those animals with problems showed significantly impaired reproductive function.
Mann
G E
GE
University of Nottingham, School of Biosciences, Division of Animal Physiology, Sutton Bonington Campus, Loughborough, UK. george.mann@nottingham.ac.uk
Keatinge
R
R
Hunter
M
M
Hedley
B A
BA
Lamming
G E
GE
D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D007774:Lactation; D008892:Milk / Q000737:chemistry*; D011247:Pregnancy; D011374:Progesterone / Q000032:analysis* / Q000097:blood; D012098:Reproduction / Q000502:physiology*
D011374:Progesterone