Injectable or transdermal flunixin meglumine improves pregnancy rates in embryo transfer recipient beef cows without altering returns to estrus

OBJECTIVES

were to determine effects of 1) injectable or transdermal flunixin meglumine (FM) at embryo transfer (ET) compared to an untreated control group on pregnancy per ET (P/ET; ∼35 d after ET); 2) embryo and recipient factors on P/ET; 3) FM on hormone concentrations; and 4) FM on returns to estrus. Angus-cross beef cows (n = 1145) at five locations were scored for body condition (BCS; 1-9) and temperament (0 or 1) and given Select-Synch + CIDR. Recipient cows with a corpus luteum (CL) ≥1.5 cm received a frozen-thawed embryo 7 d after estrus and were concurrently given 1.1 mg/kg injectable FM im (INJFM; n = 384), 3.3 mg/kg transdermal FM pour on (TDFM; n = 388), or nothing (CON group; n = 373). Blood samples were collected at ET and 7 d later (60 cows). Accounting for temperament (P < 0.05), ET difficulty score (1-3, easy to difficult; P < 0.01), treatment by temperament (P < 0.001) and treatment by embryo quality (P < 0.05), FM treatments affected P/ET (P < 0.05). The P/ET for cows given INJFM [62.8% (241/384)] or TDFM [58.7% (228/388)] were not different (P = 0.26), but they were greater (P = 0.01 and P = 0.04, respectively) than P/ET for controls [51.2% (191/373)]. The P/ET was greater for calm versus excitable cows, 60.2 (463/769) and 52.4% (197/376), respectively (P < 0.01) and was lower for difficulty score 3 [49.2% (156/317)] compared to score 1 [62.7% (254/405; P < 0.001) or score 2 [59.1% (250/423; P < 0.01)]. There was no effect (P > 0.1) of cow age, BCS, or stage of embryo development on P/ET. Pregnancy rates for embryo quality grade 1 (excellent/good) and grade 2 (fair) were 60.4% (314/520) and 55.4% (346/625), respectively (P > 0.05). Percentages of non-pregnant recipient cows in estrus from Days 18-26 did not differ among treatment groups (P > 0.1). Control cows had lower progesterone concentrations and greater substance-P, PGFM and 8-isoprostane PGF2α concentrations at 7 d after ET compared to FM-treated cows (P < 0.05). In conclusion, injectable or transdermal FM improved pregnancy rates in ET recipients, without affecting nonpregnant cows return to estrus.