Dairy Day, 2008
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Item Open Access Opportunities with low profile cross ventilated freestall facilities(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Smith, John F., 1962-; Harner, Joseph P.; Bradford, Barry J.; Overton, M.W.; jfsmith; jharner; bbradforLow profile cross ventilated freestall buildings are one option for dairy cattle housing. These facilities allow producers to control the cows’ environment during all seasons of the year. As a result, an environment similar to the thermoneutral zone of a dairy cow is maintained during both summer and winter, resulting in more stable core body temperatures. Low profile cross ventilated facilities allow buildings to be placed closer to the parlor, thus reducing the time cows are away from feed and water. Other advantages include a smaller overall site footprint than naturally ventilated facilities and less critical orientation because naturally ventilated facilities should be orientated east to west to keep cows in the shade. Other benefits of controlling the cows’ environment include increased milk production and income over feed cost, improved feed efficiency and reproductive performance, reduced lameness and fly control costs, and the ability to control lighting.Item Open Access Estimating optimal operation time of korral kools on dairy cows in a desert environment(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Ortiz, X.A.; Smith, John F., 1962-; Bradford, Barry J.; Harner, Joseph P.; Oddy, A.; jfsmith; bbradfor; jharnerDeveloping management strategies for Korral Kools will help producers provide cooling in the housing area while minimizing the operational cost of the Korral Kools system. Two experiments were conducted at a dairy in Saudi Arabia to evaluate operational time of Korral Kools for multiparous and primiparous dairy cows. For multiparous cows, running time per day of Korral Kools should be continuous, but for primiparous cows, no difference in performance was detected between 21 and 24 hours. However, producers need to be careful when reducing daily operation time of Korral Kools for primiparous cows because elevated core body temperatures were observed in both treatments.Item Open Access Resynchronized pregnancy rates in dairy cattle: timing of gonadotropin-releasing hormone injection before timed artificial insemination(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Martel, C.A.; Stevenson, Jeffrey S.; jssLactating dairy cows and replacement virgin heifers of unknown pregnancy status were treated with either gonadotropin-releasing hormone (GnRH) or saline to initiate a resynchronization program that was continued 7 days later when a not-pregnant diagnosis was determined. Nonpregnant cattle were administered prostaglandin F2α and then either injected with GnRH 56 hours later and artificially inseminated (AI) by appointment at 72 hours or injected and inseminated concurrently at 72 hours. Injection of GnRH at 56 hours produced more pregnancies than injection of GnRH at 72 hours when AI was administered at 72 hours in both treatments (30.9 vs. 15.2%). Further, starting the resynchronization with GnRH was beneficial to resulting pregnancy rates but was timing dependent. When a not-pregnant status was determined between day 30 and 36 after AI, upfront GnRH injection (7 days before pregnancy diagnosis) may not be necessary because stage of cycle is 1 to 7 days (days 3 to 4 in 71% of cattle) and resulting pregnancy rates after GnRH or saline did not differ (27.5 vs. 26.6 %, respectively). In contrast, when pregnancy status was determined after day 36 (days 37 to 43; cycle days 10 to 11 in 71% of cattle), upfront GnRH as part of the resynchronization protocol nearly doubled the number of pregnancies compared with saline (31.0 vs. 15.1%).Item Open Access Progesterone, follicular, and estrual responses to progesterone-based estrus and ovulation synchronization protocols at five stages of the estrous cycle(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Stevenson, Jeffrey S.; jssThe objective of this study was to monitor changes in ovarian status in heifers exposed to a progesterone insert with or without concurrent gonadotropin-releasing hormone (GnRH) injection. Estrus was manipulated in 283 heifers (31 breeding clusters) by administering GnRH, progesterone, and prostaglandin F2α (PGF2α) at 5 stages of the estrous cycle. Estrus was presynchronized with a progesterone insert for 7 days before PGF2α was administered 24 hours before insert removal. Successive clusters of heifers were assigned to treatments (2 heifers per treatment) on cycle day 2, 5, 10, 15, and 18. Treatments consisted of a progesterone insert (day 0) for 7 days plus (1) PGF2α on day 6, 24 hours before insert removal (early PGF); (2) GnRH on day 0 + early PGF2α (GnRH + early PGF); (3) PGF2α at insert removal (late PGF); or (4) GnRH on day 0 + late PGF (GnRH + late PGF). Controls received GnRH on day 0 and PGF2α on day 7. Ovaries were scanned by transrectal ultrasonography on days 0, 2, 7, 9, and 11 to assess follicle diameters and ovulation. Blood was collected on days 0, 2, 6, 7, 8, and 9 to quantify serum concentrations of progesterone. Insemination occurred after detected estrus or by timed artificial insemination (TAI) 64 hours after insert removal. Only 25% of 141 GnRH-treated heifers ovulated by day 2; twice as many ovulated when treatment was initiated on day 5 (46.4%) than on other cycle days (20.3%). Compared with controls, progesterone concentration was greater in all progesterone-treated heifers on days 2 and 6. Early- vs. late-PGF treatment resulted in less progesterone on days 7 and 8. Pregnancy rates were less after TAI (44%) than after detected estrus (56%) and less in controls than in all progesterone treatments. Heifers in which treatments were initiated on day 10 of the cycle had the most consistent (estrus vs. TAI) pregnancy rates (65.4%) compared with heifers in which treatments were initiated on other cycle days. Compared with controls, more progesterone-treated heifers ovulated by 96 hours after insert removal. Application of the progesterone insert reduced variance of the interval to estrus after insert removal (or PGF2α injection in controls) by 1.6-fold compared with controls. These results do not support use of GnRH in a progesterone-based synchronization protocol.Item Open Access High inclusion rate of wet corn gluten feed on performance of late-lactation holstein cows: preliminary results(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Rezac, D.J.; Grigsby, K.N.; Bradford, Barry J.; bbradforA novel diet formulation strategy incorporating wet corn gluten feed at 47% of diet dry matter was evaluated in late-lactation cows. Diets were formulated for similar protein and energy concentrations with dramatic differences in forage sources. Milk fat and protein concentrations increased with the high wet corn gluten feed inclusion rate, and this diet tended to increase milk fat yield. The preliminary work indicates that very low cost rations incorporating wet corn gluten feed may be formulated to maintain milk production, at least in late-lactation cows.Item Open Access Alfalfa hay inclusion rate in wet corn gluten feed based diets(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Mullins, C.R.; Grigsby, K.N.; Bradford, Barry J.; bbradforIn this experiment, we evaluated the effects of varying alfalfa inclusion rate in diets containing 31% wet corn gluten feed on a dry matter basis. Eighty lactating Holstein cows were allocated into groups of 10 and assigned to 1 of 8 pens balanced for parity, stage of lactation, and milk yield. Diets were formulated to contain 0, 7, 14, or 21% alfalfa on a dry matter basis. Diets containing greater proportions of alfalfa had less corn silage and soybean meal but more corn grain. Feed intake, milk production, body weight, and body condition score were monitored, and effects of increasing alfalfa inclusion rate were assessed. As more alfalfa was included in the ration, cows consumed more feed and had a tendency to produce more solids- and energy-corrected milk. In contrast, body weight gain decreased in diets with more alfalfa. These changes in milk and body weight indicate that metabolizable energy utilization shifted from body weight gain to milk production when more alfalfa was fed. With this in mind, an economic model was constructed to determine whether the added production from including alfalfa is enough to justify incorporating it in this type of ration. The model demonstrated that, despite minor losses in productivity, decreasing alfalfa inclusion rate may improve farm profitability by reducing feed costs and expenses associated with manure handling.Item Open Access Dietary molasses enhances ruminal biohydrogenation and partially alleviates diet- induced milk fat depression(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-11-23) Bradford, Barry J.; Titgemeyer, Evan C.; bbradfor; etitgemeMilk fat depression remains a problem on dairy farms, and in recent years, incorporation of distillers grains (typically with solubles added and often dried) has contributed to this problem on some farms. In this study, we evaluated whether molasses could prevent milk fat depression in cows fed a high-risk diet. Replacing up to 5% of dietary corn with cane molasses linearly increased the yield of short- and medium-chain fatty acids in milk, indicating a positive effect on de novo fatty acid synthesis in a milk fat depression environment. Molasses, however, tended to linearly decrease milk yield and linearly decreased milk protein yield, resulting in no net effect on energy- or solids-corrected milk yield. These results indicate that the potential exists for sources of dietary sugar to prevent milk fat depression, but further research is needed to determine when sugar sources might be most effective.
