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Corpus Luteum Development and Function after Supplementation of Long‐Acting Progesterone During the Early Luteal Phase in Beef Cattle
Author(s) -
Pugliesi G,
Oliveria ML,
Scolari SC,
Lopes E,
Pinaffi FV,
Miagawa BT,
Paiva YN,
Maio JRG,
Nogueira GP,
Binelli M
Publication year - 2014
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12231
Subject(s) - corpus luteum , luteal phase , beef cattle , biology , zoology , endocrinology , medicine , andrology , ovary , hormone
Contents Strategic supplementation of P 4 may be used to increase conception rates in cattle, but timing of supplementation in relation to ovulation, mass of supplementary P 4 and formulation of the P 4‐containing supplement has not been determined for beef cattle. Effects of supplementation of long‐acting progesterone ( P 4) on D ays 2 or 3 post‐ovulation on development, function and regression of corpus luteum ( CL ) were studied in beef cattle. Cows were synchronized with an oestradiol/ P 4‐based protocol and treated with 150 or 300 mg of long‐acting P 4 on D ay 2 or 3 post‐ovulation (6–7 cows/group). C olour‐ d oppler ultrasound scanning and blood sample collection were performed from D ay 2–21.5. Plasma P4 concentrations were greater (p < 0.05) from D ay 2.5–5.5 in the D ay 2‐treated groups and from D ay 3.5–5.5 in the D ay 3‐treated cows than in the control group. CL area and blood flow during D ay 2–8.5 did not differ (p > 0.05) among groups, suggesting no effect of P 4 treatment on luteal development. The frequency of cows that began luteolysis before D ay 15 was greater (p < 0.04) in cows treated with 300 mg than in the controls, but there were no differences between non‐treated and 150 mg‐treated cows. The interval from pre‐treatment ovulation to functional and structural luteolysis was shorter (p < 0.01) in the combined P 4‐treated groups than in the control cows. In conclusion, was showed for the first time that long‐acting P 4 supplementation on D ay 2 or 3 post‐ovulation increases P 4 concentrations for ≥3 day, has no effect on luteal development, but anticipates the beginning of luteolysis in beef cattle.