Fertility response of yearling beef heifers after prebreeding energy manipulation, estrous synchronization and timed artificial insemination

Baptiste, Quinn; Knights, M.; Lewis, P. E.

doi:10.1016/j.anireprosci.2004.04.036

Cited by 3 publications

(1 citation statement)

References 33 publications

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“…Positive energy balance has been reported to improve reproductive success (Dunn and Moss 1992;Keisler and Lucy 1996). However, it appears that animals in adequate nutritional status and condition do not seem to respond to increases in energy as dramatically as cattle in a nutrient-deprived state (Perkins 1984;Mattos et al 2004;Baptiste et al 2005). In experiments where short-term increases in dietary energy succeeded in improving reproduction, a brief period of nutrient restriction (nutrient intake set below maintenance requirements) was imposed prior to the increase in energy (Khireddine et al 1998;Dunne et al 1999), or treatments responses were compared with cattle on a low-plane of nutrition (Mattos et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Effects of short-term oilseed supplementation on reproductive performance in beef heifers

2011

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Scholljegerdes, E. J., Lekatz, L. A. and Vonnahme, K. A. 2011. Effects of short-term oilseed supplementation on reproductive performance in beef heifers. Can. J. Anim. Sci. 91: 221–229. The objective of this experiment was to evaluate the role of a short-term increase in linolenic acid around the timed artificial insemination (TAI) on plasma fatty acid concentrations, estrous behavior, and pregnancy. Therefore, 96 cross-bred heifers (Initial BW=394±18.1 kg) fed chopped grass hay were allotted to one of three dietary treatments: no supplement (CON); 1.8 kg head−1 d−1 (DM basis) of a soybean-based pellet (SOY) high in linoleic acid (C18:2n-6); or 1.5 kg head−1 d−1 (DM basis) of a flaxseed-based pellet (FLX) high in linolenic acid (C18:3n-3). On day −9, relative to TAI, supplementation began, and heifers received a controlled internal drug-releasing (CIDR) device and gonadotropin releasing hormone (GnRH; 100 µg). On day −2, CIDRs were removed and heifers received 25 mg prostaglandin F2α (PGF2α). Heifers were bred by TAI (day 0) 54 h after CIDR removal and received GnRH. Estrous behavior was monitored throughout the feeding period by radiotelemetry. Supplementation ended on day 18 relative to TAI. Plasma concentrations of C18:2n-6 were greater by day 0 and day 18 (P<0.001) above that of CON for both SOY and FLX with SOY being greater than (P<0.001) FLX. Likewise, C18:3n-3 was also greater for supplemented heifers by day 0 and day 18 (P<0.001). The number of heifers that did not respond to estrous synchronization was not affected by dietary treatment (P=0.61). Conception to AI was not affected by treatment (P=0.24). Overall pregnancy rates tended to be lower for FLX (P=0.08) than SOY. Conception to a TAI program was not enhanced when oilseeds were fed to beef heifers during estrous synchronization and continuing past day 18 relative to artificial insemination.

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