Dairy Day, 1992

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  • ItemOpen Access
    Administering a GnRH agonist (receptal) after insemination fails to improve pregnancy rates at first service
    (Kansas Agricultural Experiment Station, 2011-05-20) Rettmer, I.; Stewart, R.E.; Stevenson, Jeffrey S.; jss
    Two experiments were performed to determine the influence of administering a highly potent agonist of gonadotropin-releasing hormone (Receptal) on various reproductive characteristics in dairy cows. In Experiment 1, lactating Holstein cows were treated with either saline (n = 51) or 8 μg of receptal (n = 50) on d 11 to 14 after estrus (d 0) and first service. Peak concentrations of LH, FSH, and progesterone, but not estradiol-17b, in blood serum were increased during 6 to 12 h after injection of Receptal. Pregnancy rates were unaffected by treatment. Concentrations of progesterone in blood serum were increased in nonpregnant and pregnant cows after injection of Receptal. Return to estrus in Receptal-treated cows increased by 2.5 ± .8 days compared to controls. The number of follicles >10 mm in diameter, assessed by transrectal ultrasonography, were reduced and follicular development was altered after Receptal. In Experiment 2, various doses of Receptal were tested in eight dairy herds, including 1,013 inseminations at first service. Cows were given a single injection of either saline or 4, 8, or 12 μg of Receptal on days 11 to 14 after first service. Pregnancy rates were not improved consistently in all herds and failed to increase across all herds. We concluded that administering a potent GnRH agonist altered number and distribution of ovarian follicles, increased cycle length, and increased concentrations of progesterone, without a consistent increase in fertility.
  • ItemOpen Access
    Induction of estrus in thyroidectomized-ovariectomized, nonlactating, holstein cows
    (Kansas Agricultural Experiment Station, 2011-05-20) Stewart, R.E.; Mee, M.O.; Rettmer, I.; Stevenson, Jeffrey S.; jss
    Low thyroid activity (hypothyroidism) has been reported to decrease sexual behavior associated with reproduction in several species. Using estradiol benzoate (EB) and progesterone (P ), we attempted to induce 4 estrus in hypothyroid cows. Thyroid glands (thyroidectomy) and ovaries (ovariectomy) were removed surgically from nonlactating and nonpregnant Holstein cows that were culled from the Kansas State University dairy herd. Eight cows were thyroidectomized and ovariectomized (THYOVEX) and another four cows were ovariectomized only (OVEX). Starting 9 hr after injection of EB, cows were continuously observed for estrus for 36 hr. Frequencies of mounting activity and standing behavior were recorded for each cow. The percentage showing standing estrus was greater in cows that had no thyroid glands or ovaries than in cows without ovaries (78 vs 31%). Manifestation of estrus was identical in cows treated with EB or EB+P (62%). Interval from 4 EB injection to onset of standing estrus, frequency of mounting activity, and duration of standing estrus were similar among treatment groups and unaffected by the type of hormonal treatment. Thyroidectomized cows can exhibit estrous behavior, which is similar to that in ovariectomized cows treated with EB or P +EB.
  • ItemOpen Access
    Ovarian follicular waves and secretion of follicle-stimulating hormone after administration of GnRH at estrus
    (Kansas Agricultural Experiment Station, 2011-05-20) Pursley, J.R.; Stevenson, Jeffrey S.; jss
    An experiment was conducted to examine the effects of GnRH on the secretion of FSH, LH, estradiol, and progesterone in serum and changes in ovarian structures. Dairy cows were assigned randomly to receive either 100 μg of GnRH or saline 12 hr after estrus (day 0) was detected. Blood was collected daily to assess changes in serum estradiol and progesterone and every 12 min for 8 hr on days 8 and 15 after estrus to assess concentrations of FSH and LH. Diameter and number of follicles were determined daily by real-time ultrasonography. Two patterns of follicular development were observed. The day of peak diameter of each dominant follicle (three or four per cycle) was synchronous with increases in estradiol in serum. The dominant follicle grew at a faster rate in all GnRH-treated cows. We concluded that administering GnRH at estrus increased the pulse frequency of FSH on days 8 and 15 of the cycle, altered follicular dynamics of dominant follicles of the subsequent estrous cycle, and tended to increase concentrations of progesterone in serum of cows.
  • ItemOpen Access
    Effect of yearly milk production on average days open
    (Kansas Agricultural Experiment Station, 2011-05-20) Call, Edward P.; epcall
    Although there is a genetic antagonism between yearly production per cow and reproduction, analysis of Kansas Holstein herds suggests that managers of higher producing herds overcome this inverse relationship. Higher producing herds have fewer cows open at any given time, and those cows that are open average fewer days since last freshening. When open cows are categorized by days open, higher producing herds have fewer cows open more than 60 days, and especially fewer cows open more than 120 days.
  • ItemOpen Access
    Somatic cell count inversely related to potential profits in dairying
    (Kansas Agricultural Experiment Station, 2011-05-12) Dunham, James R.
    Somatic Cell Count (SCC) affects productivity of a dairy herd and, thus, potential profit. Almost all SCC problems can be solved by management. The DHIA SCC program is very useful for evaluating the situation in a dairy herd to solve such problems.
  • ItemOpen Access
    Leukocyte function in vitro after adding vitamins A, E, and Beta-Carotene
    (Kansas Agricultural Experiment Station, 2011-05-12) Eicher, S.D.; Morrill, J.L.; Blecha, Frank
    Blood neutrophils and pulmonary alveolar macrophages isolated from calves at 3 and 6 wk of age were cultured in medium without added vitamins or supplemented with vitamin A, vitamin E, vitamin A and vitamin E, or ßcarotene and vitamin E. Macrophage bactericidal activity improved with A-E supplementation compared to ß-carotene-E supplementation at wk 3. Neutrophil bactericidal activity decreased with all vitamin E treatments at wk 3 and with vitamins E and A-E at wk 6. Neutrophil phagocytosis improved at wk 3 with A, E, and A-E supplementations. The chemotactic index improved at wk 3 with ß-carotene- E compared to vitamin E alone and at wk 6 with vitamin E compared to vitamin A and control treatments. The retinol content of neutrophils at wk 3 was variable, but by wk 6, cells supplemented with A, E, or A-E had higher retinol concentrations than control cells. Neutrophil a-tocopherol concentrations at 3 wk increased over controls with vitamin E or ßcarotene- E supplementation, but at wk 6, vitamin E-supplemented cells were different only from vitamin A-supplemented cells. These data suggest that there are optimum plasma concentrations of vitamins A and E for leukocyte functions.
  • ItemOpen Access
    Evaluation of roasted soybeans for dairy calves
    (Kansas Agricultural Experiment Station, 2011-05-12) Reddy, P.V.; Morrill, J.L; Bates, L.S.
    Diets containing soybeans roasted at different temperatures were fed to calves to investigate effects on growth and feed consumption. A growth trial was conducted using 84 Holstein calves from birth to 8 wk of age. The diets were formulated to contain 18% CP using soybeans roasted at 270 degrees F, 295 degrees F, or 325 degrees F. The overall feed consumption was greater for calves fed the diet containing beans roasted at either 270 or 295 degrees F than those fed the diet containing 325 degrees F beans. A similar trend was observed in weekly feed consumption. Gains were higher for calves fed the diet containing 295 degrees F beans, and these calves were more efficient in converting feed and energy to gain than the others. Rumen undegradable intake protein increased with increasing roasting temperature, but unavailable protein was high for 325 degrees F beans. Superior calf performance resulted when corrected undegradable intake protein (undegradable intake protein "minus" indigestible intake protein) was 56% and trace lipase activity remained.
  • ItemOpen Access
    Fish meal as a protein source for holstein steer calves
    (Kansas Agricultural Experiment Station, 2011-05-12) Morrill, J.L.; Laster, J.F.; Morrill, J.M.; Feyerherm, A.M.
    Holstein steer calves (n = 96) were on experiment from 8 to 18 wk of age. Control calves were fed a diet in which all supplemental protein was from soybean meal; in the experimental diet, part of the soybean meal was replaced by fish meal. Both feeds were readily consumed, and consumption did not differ between treatments. Gains of calves fed fish meal were greater (P = .10) during the first 8 wk of the experiment; however, over the entire experiment, the difference was not significant. Overall results suggest that fish meal may improve weight gains and feed efficiency of younger and smaller calves.
  • ItemOpen Access
    Waste management in the production dairy indistry
    (Kansas Agricultural Experiment Station, 2011-05-12) Fulhage, C.
    The impact of environmental regulation on livestock production enterprises is, inevitably, an increase in production costs. Producers should recognize that these are the costs of doing business and will probably have to be incurred by all producers who stay in business and remain viable. With proper input to the regulation process and implementation of practical and effective methods of manure management, most producers should be able to maintain viable enterprises.
  • ItemOpen Access
    Waste management: regulations and problems in Kansas
    (Kansas Agricultural Experiment Station, 2011-05-12) Harner, Joseph P.; Murphy, James P.; jharner
    The dairy industry is receiving greater pressure to reduce its potential pollution to the environment. As the demand grows for cleaner streams, dairy operations will need to reduce and control the nutrient and sediment loading of the runoff leaving the farm vicinity. Existing dairy operations will need to evaluate the impact of manure storage and management on the environment. Costs of controlling the runoff must be weighed against new lot construction in an alternate location. Future dairy facilities will need to address current regulations and be designed for compliance with future and more stringent regulations.