03245naa a2200289 a 450000100080000000500110000800800410001902400350006010000170009524501790011226000090029152023650030065000280266565000170269365000160271065300130272665300150273970000170275470000200277170000230279170000180281470000170283270000220284970000170287170000210288877300460290920296302019-11-18       2019    bl uuuu     u00u1 u    #d7 a10.1017/S17517311190004422DOI1 aNOGUEIRA, E.  aTimed artificial insemination plus heat Ibeffect of estrus expression scores on pregnancy of cows subjected to progesterone-estradiol-based protocols.h[electronic resource]  c2019  aExpression of estrus near timed artificial insemination (TAI) is associated with greater fertility, and estrus detection could improve TAI fertility or direct TAI management, although accurate estrus detection can be difficult and time-consuming using traditional methods. The aim of this study is to evaluate influence of estrus on pregnancy (artificial insemination pregnancy rates (P/AI)) and to validate an alternative method to classify estrus/heat expression using tail chalking (HEATSC) in postpartum Bos indicus cows subjected to TAI in progesterone?estrogen-based protocols. In experiment 1 (Exp. 1), cows (5491) were subjected to visual observation of estrus after progesterone device removal, before TAI, and P/AI was evaluated according to estrus and body condition score (BCS). Cows received a progesterone device and 2mg estradiol benzoate (EB). After 8 days, the device was removed and 150 ?g of D-cloprostenol and 300 IU equine chorionic gonadotrophin was given. Later, animals in Exp. 1 received 1mg EB and TAI 44 to 48 h. In the Exp. 2 ? 3830 cows using similar protocol, received different ovulation inducers: 1mg EB (n=1624) or 1mg estradiol cypionate (EC; n=2206) on day 8 (D8). Cows were then marked with chalk, and HEATSC evaluated at TAI on D10 (HEATSC1 ? no chalk removal =no estrus expression; HEATSC2 ? partial chalk removal =low estrus expression; HEATSC3 ? near complete/complete chalk removal =high estrus expression). In Exp. 1, cows showing estrus presented greater P/AI (48.4% v. 40.2%, P&lt0.05). In Exp. 2, P/AI (HEATSC1 ? 40.0%; HEATSC2 ? 49.7%; HEATSC3 ? 60.9%; P&lt0.001), and larger follicle timed artificial insemination (LFTAI) (&lt0.001) varied according to HEATSC. There was no difference in P/AI ( P=0.41) or LFTAI ( P=0.33) according to ovulation inducer. Cows with greater BCS showed greater P/AI in both experiments ( P&lt0.05). Estrus presence and greater HEATSC improved P/AI, and EC v. EB used promoted differential estrus manifestation (cows showing HEATSC2 and HEATSC3: 79.5% with EB v. 69.98% with EC use, P&lt0.001), however, with similar P/AI. The use of HEATSC in B. indicus cows subjected to TAI is useful to identify cows with greater estrus expression and consequently improved pregnancy rates in TAI, allowing the cows with low HEATSC to be targeted for additional treatments aimed at improving P/AI.  aArtificial insemination  aReproduction  aBos Indicus  aFollicle  aHeat score1 aSILVA, M. R.1 aSILVA, J. C. B.1 aABREU, U. G. P. de1 aANACHE, N. A.1 aSILVA, K. C.1 aCARDOSO, C. J. T.1 aSUTOVSKY, P.1 aRODRIGUES, W. B.  tAnimalgv. 13, n. 10, p. 2305-2312, 2019.