Colazo, M.

Escobedo Granados, Oscar

López de Armentia Oses, Leire

Noya Clavé, Agustí

Rodríguez Sánchez, José Antonio

Sanz Pascua, Albina

citaREA Repositorio Electrónico Agroalimentario

EAAP – 73rd Annual Meeting, Porto, Portugal, 2022 671Session 67 Poster 13Session 67 Theatre 12Administration of eCG is not recommended in time-AI protocols for beef cattle in good body conditionA. Sanz1, A. Noya1, O. Escobedo†1, M. Colazo2, L. López De Armentia1 and J.A. Rodríguez-Sánchez31CITA de Aragón – IA2 (Universidad de Zaragoza), Av Montañana 930, 50059 Zaragoza, Spain, 2University of Alberta, T6G 2P5, Edmonton, Canada, 3Terraiberica Desarrollos S.L., 44001, Teruel, Spain; asanz@aragon.esThe main objective of this study was to examine the effect of equine chorionic gonadotropin (eCG) administration on pregnancy per AI (P/AI) in Angus and Angus × Avileña cattle subjected to a 7-d ovulation synchronization protocol. On Day 0 (11:00), heifers (n=36, 460 kg, 3.7 BCS, 2.1 years old) and cows (n=256, 594 kg, 2.8 BCS, 4.8 years old) were randomly assigned to one of two intravaginal progesterone (P4) inserts (PRID 1.55 g, Ceva S.A., Spain or CIDR 1.38 g, Zoetis, Spain). On Day 7 (16:00), the P4 insert was removed, 500 μg of dinoprost (Enzaprost, Ceva S.A.) administered im and females were further subdivided to receive or not 500 IU of eCG im (Foligon, Merck Sharp & Dohme Animal Health, S.L., Spain). On Day 10 (11:00), all cattle received 100 μg of GnRH (Cystoreline, Ceva S.A.) and were inseminated by one technician with semen from three sires equally distributed among treatments. Ovarian ultrasonography was done in a subset of 47 cows at Day 0 and in all cattle 35 days after AI to determine cyclicity and pregnancy status, respectively. Data were analysed by Chi-square using FREQ and GLM procedures (SAS v 9.4). Three cows out of 47 cows were acyclic and remained non-pregnant, showing all of them a similar BCS (3.2). The overall P/AI was 51% (149/292). Cattle category, breed, P4 insert type or the inclusion of eCG did not affect P/AI (51 vs 52%, with and without eCG; P=0.890). Sire tended to affect P/AI (46, 45 and 60%; P=0.066). BCS did not differ between cattle that became pregnant or not. In summary, the inclusion of eCG did not affect P/AI, therefore, its use is not recommended in ovulation synchronization protocols for suckler cows and heifers in good body condition score, in order to reduce costs. Funded by Project FITE 2019 VACAFERTILTERUEL, Government of Aragón and FEDER.Performance of first parity Holstein, Danish Red and their crosses in an experimental settingJ.B. Clasen1, H.M. Nielsen1, L. Hein2, K. Johansen1, M. Vestergaard3 and M. Kargo11Aarhus University, Center for Quantitative Genetics and Genomics, Blichers Allé, 8830 Tjele, Denmark, 2SEGES, Agro Food Park, 8200 Aarhus N, Denmark, 3Aarhus University, Animal Science, Blichers Allé, 8830 Tjele, Denmark; julie.clasen@qgg.au.dkCrossbreeding between dairy cattle breeds is becoming popular in dairy production, calling for scientifically based comparison of breeds and their crosses for traits other than milk production. Crossbreeding experiments and breed comparisons conducted in controlled research environments are scarce. This study presents results from an on-station crossbreeding experiment in Denmark, including 16 first parity Holstein, 13 Danish Red and 16 F1 Danish Red × Holstein. The heifer calves were purchased at 4 weeks of age and was fed at either a low or medium feeding level as heifers. They began their first lactation between July and September 2021. Cows were housed in one group, fed the same total mixed ration (41% DM), and were otherwise handled equally. Data on daily milk yield, body weight, individual DM intake and pregnancy rate at first AI were analysed using a mixed model in SAS and compared between breeds and heifer feeding level. Preliminary results show that, in the period between 10 and 140 days in milk, daily DM intake was similar (P>0.05) between breed groups (17.2 to 18.0 kg DM/d), but cows fed at the low feeding level as heifers had a significantly higher (P<0.05) DM intake. There were significant differences (P<0.05) in milk yield between breed groups, but no effect of heifer feeding level. Crossbred cows produced 32.3 kg ECM per day, Holstein 29.7 kg, and Danish Red 26.2 kg. Danish Red cows tended to gain (1.5 kg/week) more than Holstein (0.5 kg/week) but significantly (P<0.05) more than crossbreds (-0.05 kg/week). Cows fed at a low feeding level as heifers gained significantly more than cows fed at a medium feeding level. The pregnancy rate at first AI was 66.7% for Danish Red, 53.8% for Holstein, and 57.1% for crossbreds. The conclusions so far are: (1) that given the same environment and feed intake, the two pure breeds may allocate energy intake differently for lactation and growth; and (2) the crossbred cows show a large and favourable heterosis for milk production.Book of Abstracts of the 73rd Annual Meeting of the European Federation of Animal ScienceBook of abstracts No. 28 (2022) Porto, Portugal5 – 9 September, 2022

Administration of eCG is not recommended in time-AIprotocols for beef cattle in good body condition (póster)

https://citarea.cita-aragon.es/citarea/bitstream/10532/6085/1/2022_350.pdf

Administration of eCG is not recommended in time-AIprotocols for beef cattle in good body condition (póster)

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