title: Effects of flunixin meglumine, recombinant bovine somatotropin and/or human chorionic gonadotropin on pregnancy rates in Nelore cows.
abstract: The objective was to compare pharmacological strategies aiming to inhibit prostaglandin F2 alpha (PGF(2α)) synthesis (flunixin meglumine; FM), stimulate growth of the conceptus (recombinant bovine somatotropin; bST) and progesterone (P(4)) synthesis (human chorionic gonadotropin; hCG), as well as their combinations, regarding their ability to improve pregnancy rates in beef cattle. Lactating Nelore cows (N = 975), 35 to 70 days postpartum, were synchronized and inseminated by timed artificial insemination (TAI) on Day 0. On Day 7, cattle were allocated into eight groups and received one of the following treatments: saline (S) on Days 7 and 16 (Group Control); S on Day 7 and FM on Day 16 (Group FM); bST on Day 7 and S on Day 16 (Group bST); bST on Day 7 and FM on Day 16 (Group bST + FM); hCG on Day 7 and S on Day 16 (Group hCG); hCG on Day 7 and FM on Day 16 (Group hCG + FM); bST and hCG on Day 7 and S on Day 16 (Group bST + hCG), or bST and hCG on Day 7 and FM on Day 16 (Group bST + hCG + FM). The aforementioned treatments were administered at the following doses: 2.2 mg/kg FM (Banamine®; Intervet Schering-Plough, Cotia, SP, Brazil), 500 mg bST (Boostin®; Intervet Schering-Plough), and 2500 IU hCG (Chorulon®; Intervet Schering-Plough). Pregnancy diagnosis was performed 40 days after TAI by transrectal ultrasonography. Pregnancy rates were not significantly different among treatments. However, there was a main effect of hCG treatment to increase pregnancy rates (63.0 vs. 55.4%; P = 0.001). Concentrations of P(4) did not differ significantly among groups on Day 7 or on Day 16. However, consistent with the higher pregnancy rates, hCG increased P(4) concentrations on Day 16 (10.6 vs. 9.6 ng/mL, respectively; P = 0.05). We concluded that hCG treatment 7 days after TAI improved pregnancy rates of lactating Nelore cows, possibly via a mechanism leading to induction of higher P(4) concentrations, or by reducing the luteolytic stimulus during maternal recognition of pregnancy.
authors: São Paulo State University (UNESP), Araçatuba, São Paulo, Brazil.
authors: R C
authors: RC
authors: Rossetti
authors: A
authors: A
authors: Perdigão
authors: F S
authors: FS
authors: Mesquita
authors: M
authors: M
authors: Sá Filho
authors: G P
authors: GP
authors: Nogueira
authors: R
authors: R
authors: Machado
authors: C M B
authors: CM
authors: Membrive
authors: M
authors: M
authors: Binelli
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003002:Clonixin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015237:Dinoprost / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*
chemical_list: D006063:Chorionic Gonadotropin; D011374:Progesterone; C014558:flunixin meglumine; D013006:Growth Hormone; D015237:Dinoprost; D003002:Clonixin