Dairy Day, 2010
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Item Open Access Ovarian characteristics, serum hormone concentrations, and fertility in lactating dairy cows in response to equine chorionic gonadotropin(Kansas Agricultural Experiment Station and Cooperative Extension Service, 2012-09-07) Pulley, Stephanie Leeann; Wallace, L.D.; Mellieon, H.I.; Stevenson, Jeffrey S.; jssThe objective of this study was to evaluate the effects of equine chorionic gonadotropin (eCG) on various characteristics associated with an effective timed artificial insemination (AI) protocol in lactating dairy cows. Cows (n = 121) in a single herd were treated with 2 injections of prostaglandin F2α (PGF2α) 14 days apart (Presynch), with the second injection administered 11 days before the onset of a timed AI protocol. Cows received either saline or 400 IU eCG concurrent with the PGF2α injection of the Ovsynch protocol (injection of gonadotropinreleasing hormone or GnRH, 7 days before and 48 to 56 hours after PGF2α with insemination occurring 12 to 16 hours after the second GnRH injection). Blood samples were collected during the study to monitor serum changes in progesterone and estradiol in order to determine if eCG would facilitate increased estrual activity, improved ovulatory response, and enhanced postovulatory luteal function. Administration of eCG tended to increase the number of corpora lutea (CL) and on days 9 and 16 after PGF2α, corresponding to days 6 and 13 postovulation, but the volume of the luteal tissue was less than that in the control. Timed AI pregnancy rates did not differ between eCG (36.9%) and control cows (41.8%). We concluded that use of eCG provided no profertility advantages to dairy cattle when programmed for a timed insemination at first service.Item Open Access Bioavailability of lysine from hydroxymethyl lysine(Kansas Agricultural Experiment Station and Cooperative Extension Service, 2012-09-07) Elwakeel, E.A.; Titgemeyer, Evan C.; Brake, D.W.; Nour, A.M.; Nassar, M.E.; Faris, Brian R.; etitgeme; brfarisTwelve mature sheep were used as a ruminant model to estimate the bioavailability of lysine in hydroxymethyl lysine (HML) compared with a commercial product of rumen-protected lysine (RPL; LysiPEARL, Kemin Industries, Inc.) with known availability. The sheep were fed a diet with a forage to concentrate ratio similar to that of dairy diets. Following a control period in which plasma lysine was measured when sheep received no supplemental lysine, the sheep were provided 2 of 4 treatments during periods 2 and 3; treatments included RPL to provide 3 or 6 g/day of available lysine (actual amounts of product provided were based on the manufacturer’s data related to ruminal escape and intestinal availability) and 3 or 6 g/day of lysine provided as HML. Blood samples were collected at the end of each feeding period at 3 hours after feeding. Both HML and RPL significantly increased plasma lysine concentrations. By comparison with plasma lysine concentrations when known amounts of bioavailable lysine were provided as RPL, the bioavailability of lysine in HML was estimated to be 94%. Results indicate that HML may be an effective means of supplementing lysine to dairy cattle.Item Open Access Lysine degradation by ruminal Fusobacterium necrophorum(Kansas Agricultural Experiment Station and Cooperative Extension Service, 2012-09-07) Elwakeel, E.A.; Amachawadi, R.G.; Nour, A.M.; Nassar, M.E.; Nagaraja, Tiruvoor G.; Titgemeyer, Evan C.; tnagaraj; etitgemeThree experiments were conducted to characterize lysine fermentation by Fusobacterium necrophorum, a ruminal bacterium that is known to degrade amino acids. In Experiment 1, 7 strains of Fusobacterium necrophorum were inoculated into media containing lysine (50 mM), lactate (50 mM), or lysine plus lactate (50 mM each) as the major energy substrate to evaluate growth and ammonia production. All strains grew with lysine, lactate, or lactate plus lysine as the primary substrate. When grown with lysine, all strains produced ammonia as an end product, even if lactate was also present. Smaller concentrations of ammonia for medium containing lactate plus lysine when compared with lysine alone indicate that the Fusobacterium strains used lactate as a growth substrate that stimulated utilization of ammonia. In Experiment 2, the 2 strains tested were able to degrade extensively both lysine and glutamic acid. Some evidence was detected for partial utilization for growth of histidine, methionine, and tryptophan by strain A21. In Experiment 3, the minimum inhibitory concentration (MIC) of the antibiotic tylosin was 25 μg/mL when Fusobacterium necrophorum strains A21 and B35 were grown in either lysine or lactate-enriched medium. The MIC of monensin was 6.25 and 3.9 μg/mL for strains A21 and B35, respectively, when grown in lysine-enriched medium, but > 50 and 10.9 μg/mL when the strains were grown in lactate-enriched medium. These findings may lead to ways that ruminal lysine degradation may be controlled.Item Open Access Effects of wet corn gluten feed and dietary particle size on ruminal fermentation and milk production(Kansas Agricultural Experiment Station and Cooperative Extension Service, 2012-09-07) Sullivan, M.L.; Bradford, Barry J.; bbradforWet corn gluten feed (WCGF) was included in 4 diets at 0, 11, 23, and 34% of diet dry matter. Alfalfa hay was used to maintain at least 10% of particles ≥ 0.71 inches in length (the top screen of the Penn State Particle Separator) in all diets. Ruminal probes were placed in the rumens of 7 ruminally cannulated lactating Holstein dairy cows to measure ruminal pH. As WCGF increased in the diet, dry matter intake and milk production increased quadratically with 23% WCGF supporting the highest feed intake and milk yield. Ruminal pH and milk fat content were similar across all diets.
