Evidence for maternal behavior as a requisite link in suckling-mediated anovulation in cows.
Some component of the suckling process inhibits LH secretion and delays postpartum ovulation in beef cows. To investigate a possible role for maternal behavior in suckling-mediated anovulation, 27 crossbred beef cows were randomly allotted to 1 of 3 groups: 1) alien (dam suckled by alien calf; n = 11); 2) own (dam suckled by own calf; n = 8); and 3) weaned (calf removed for 6 days; n = 8). Beginning 14-17 days after parturition (experimental Day 0), cows were control suckled (10 min every 6 h) in stanchions for 6 days by either their own calf or by an alien calf or were weaned. Mean LH pulse frequencies in the alien and weaned groups were similar but were elevated (p < 0.02) on experimental Days 2 and 4 compared to those in the own group. The incidence of luteal activity by experimental Day 10 was greater (p < 0.01) for the alien (72.2%) and weaned groups (75.0%) than for the own group (12.5%). Frequency of oxytocin release following suckling was greater (p < 0.01) in the own group than in the alien group (Day 2: 100% vs. 36.4%; Day 4: 100% vs. 54.6%), whereas suckling-induced release of prolactin was similar for both groups. Data provide evidence that the mother-offspring bond is an important link in suckling-mediated inhibition of LH secretion and ovulation.
Silveira
P A
PA
Animal Reproduction Laboratory, Texas A&M University System, Beeville 78102.
Spoon
R A
RA
Ryan
D P
DP
Williams
G L
GL
D000374:Aggression; D000818:Animals; D000833:Animals, Suckling / Q000502:physiology; D000858:Anovulation; D002417:Cattle / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D007774:Lactation / Q000502:physiology*; D007986:Luteinizing Hormone / Q000378:metabolism; D008425:Maternal Behavior / Q000502:physiology*; D010121:Oxytocin / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism
D010121:Oxytocin; D011388:Prolactin; D007986:Luteinizing Hormone