Dairy Day, 1991
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Item Open Access Pregnancy rates of holstein cows after postinsemination treatment with progesterone(Kansas Agricultural Experiment Station, 2011-08-02) Stevenson, Jeffrey S.; Mee, M. O.; jssThe objective of this experiment was to determine if pregnancy rates following first services would be improved by supplementing lactating dairy cows with progesterone during two phases after insemination. Cows were inseminated at estrus (day 0), and progesterone was administered via a progesterone-releasing intravaginal device (PRID) from days 5 to 13 or days 13 to 21 after first service with untreated cows serving as controls. Pregnancy rates at first services were unaffected by the progesterone treatments whether the cows received a PRID from days 5 to 13 (13/36 or 36%), a PRID from days 13 to 21 (18/36 or 50%), or no PRID (39/92 or 42%). Fewer nonpregnant cows receiving the PRID returned to estrus 17 to 27 days after the first service compared to the controls (27 vs. 49%). However, this apparently was not associated with improved embryonic survival in the cows receiving progesterone because the pattern of cows returning to estrus after first service was similar, except for 17 to 27-day period cited above. Supplementing progesterone to lactating dairy cows after first services did not seem to improve fertility.Item Open Access Release of parasitic wasps to control stable flies in Kansas dairies(Kansas Agricultural Experiment Station, 2011-08-02) Greene, G. L.After release of fly parasites in Kansas dairies during 1991, parasitism increased from May to late June then dropped in July. The parasite released was Spalangea nigroaenea of Kansas origin to assure its adaption to Kansas conditions. Additional studies of fly parasite releases are needed to develop a reliable fly reduction program for Kansas dairies before fly parasite purchases can be reliably recommended. Release of adapted parasite species and removal of fly breeding areas will be essential for reduction of fly numbers at Kansas dairies.Item Open Access Severe flea infestation in dairy calves(Kansas Agricultural Experiment Station, 2011-08-02) Dryden, Michael W.; Broce, A. B.In June 1991, an investigation was conducted of a severe flea infestation in 23 Holstein dairy calves in South Central Kansas. Inspection of the dairy revealed massive numbers of fleas on calves and in the barn where they were housed. Analysis of blood samples from 10 calves revealed that nine of them had mild to severe anemia. A management program was initiated consisting of treatments of calves and premises with insecticide and insect growth regulator and removal of straw bedding from the barn. Inspection of the dairy 9 wk after this complete control program was initiated revealed that fleas were not evident on calves or on the premises.Item Open Access Leukocyte function and health status of calves supplemented with vitamins A and E(Kansas Agricultural Experiment Station, 2011-08-02) Eicher-Pruiett, S. D.; Morrill, J. L.; Blecha, Frank; Chitko-McKown, C. G.; Anderson, N. V.; jmorrillForty-four Holstein calves were fed milk replacers with varied concentrations of vitamins A and E from 3 to 45 d of age to determine their effects on concentrations of plasma vitamin A (retinol and retinyl palmitate) and vitamin E (a- tocopherol), lymphocyte and neutrophil functions, and health of calves. Plasma a-tocopherol was unaffected by increased vitamin A supplementation. Fecal scores, and eye and nose membrane responses were improved with increased vitamin A and lower vitamin E concentration, whereas the same treatment tended to reduce neutrophil cytotoxic and bactericidal activity by 6 wk of age. Increased supplemental vitamin E tended to enhance neutrophil functions. However, age appeared to have an effect on response to both vitamins.Item Open Access Performance of holstein heifers reared on 100 or 115% of NRC requirements from 3 to 12 months of age and then switched to the opposite treatment(Kansas Agricultural Experiment Station, 2011-08-02) Bortone, E. J.; Daccarett, M. G.; Morrill, J. L.; Stevenson, Jeffrey S.; Feyerherm, A. M.; jmorrill; jssHolstein heifers from the Kansas State University Dairy Teaching and Research Unit were used from 3 mo of age until 21 d before estimated date of calving. They were fed either 100 (control, C) or 115% (enhanced, E) of the 1989 National Research Council (NRC) requirements for major nutrients from 3 to 12 mo of age, then, until 21 d before freshening, the treatments were switched from 100 to 115% NRC (CE) or from 115 to 100% NRC (EC). At puberty, heifers had similar body weights (613, E vs 617, C) but heifers fed E were 1 month younger (11 vs 12 mo). Heifers fed the E diet were heavier and had larger heart girth at 12 mo of age than the group fed C. After switching, the group fed CE increased more in body weight, body length, wither height, and body condition than the group fed EC.Item Open Access Performance of holstein calves from three to twelve months of age(Kansas Agricultural Experiment Station, 2011-08-02) Velazco, J.; Morrill, J. L.; Brandt, Robert T., Jr.; Schalles, R.; jmorrillSixty-four Holstein steers were used to study the effect of season and age on performance. Animals beginning the trial in spring were heavier (P<.05) and more efficient than calves started in other seasons. There were no differences (P>.05) among seasons in average daily gain and feed conversion after 6 mo of age. Rate of growth was reduced after 9 mo of age for all seasons.Item Open Access Heifer feeding and management affect efficiency(Kansas Agricultural Experiment Station, 2011-08-02) Dunham, James R.; dunhamHeifer feeding and management programs have a great impact on the efficiency of the future dairy herd. Dairies that feed and manage heifers for calving at about 24 mo of age are optimizing milk production, feed cost for raising heifers, number of replacement heifers available, and return on investment. Replacement heifers represent a considerable investment in labor and feed, with no return on that investment until they freshen. A summary of Kansas DHIA Holstein herds shows that some herds are receiving a good return on investment as early as 22 mo of age, whereas other herds are not reaping any return until 31 mo (Figure 1). The summary also shows that herds with heifers freshening at an average age of 24 to 25 mo have the highest Rolling Herd Averages for milk production.Item Open Access Effects of aspergillus oryzae extract (amaferm) on ruminal fibrolytic bacteria and in vitro fiber degradation(Kansas Agricultural Experiment Station, 2011-08-02) Beharka, A. A.; Nagaraja, Tiruvoor G.; tnagarajThe effect of Amaferm on growth of pure cultures of ruminal cellulose-digesting, hemicellulose- digesting and pectin-digesting bacteria was determined. The addition of Amaferm to the growth medium increased the growth of Ruminococcus albus and Fibrobacter succinogenes. Amaferm had no effect on the growth of the other bacteria. Additionally, selective antimicrobial compounds were used to assess the influence of Amaferm on microbial contributions to in vitro fiber degradation. Amaferm appeared to stimulate fiber digestibility of only certain feedstuffs, and this increase in digestibility was attributed to its stimulation of bacterial activity. Amaferm did not appear to stimulate fungal activity.Item Open Access The effect of processed soybeans and added energy in calf starters on the growth of holstein calves(Kansas Agricultural Experiment Station, 2011-08-02) Reddy, P. V.; Morrill, J. L.; jmorrillIn Trial 1, 91 Holstein calves were fed starters containing either soybean meal (SBM), extruded soybeans (ESB), roasted soybeans (RSB), SBM+soy oil (SO), or SBM+rumen inert fat (RIF) from birth to 10 wk of age. There were no differences in overall feed consumption, except that calves fed RSB consumed more than calves fed SBM+SO. There were no significant differences in weight gains, but calves fed SBM+SO tended to gain less. In trial 2, 71 Holstein calves were fed starters containing roasted soybeans from birth to 10 wk of age. Three of the starters contained 18% protein and soybeans roasted at 210, 260, or 290 F; the fourth starter contained 15% protein and soybeans roasted at 260 F. Calves fed starter containing soybeans roasted at 290 F consumed more feed, gained more weight, and were more efficient in converting feed and energy to gain than were the other calves fed 18% protein. Feed consumption was high and gains were intermediate by calves fed starter containing 15% protein. Growth in body size correlated with weight gains.Item Open Access Performance of mid-lactating dairy cows fed a grain sorghum-soybean silage base diet(Kansas Agricultural Experiment Station, 2011-08-02) Hartadi, H.; Harbers, L.; Shirley, John E.; Bolsen, K.; lenhar; jshirleyWhole-plant silage from intercropped grain sorghum and Williams 82 soybean was compared to corn silage in a mixed diet for mid-lactation dairy cows. Cows fed the grain sorghum-soybean silage yielded 45.13 lb and those fed corn silage yielded 44.05 lb of fat (4%)-corrected milk daily. Milk yield, milk fat, and milk lactose percentages were similar between cows fed the two silages. Protein and solids non-fat percentages for the cows fed the corn silage diet were .09 and .06 units greater than those of cows fed the grain sorghum silage. Cows fed the corn silage tended to gain more (+105.8 lb) than those fed the grain sorghum-soybean silage (+95.2 lb). We conclude that, if the cost for producing intercropped grain sorghum and soybean silage (ton/acre) is at least similar to that of producing corn silage, the intercropped grain sorghum and soybean silage can be substituted for corn silage in a mid-lactation dairy cow diet.Item Open Access Administration of GnRH at insemination in repeat breeding dairy cows: improved pregnancy rates, hormone secretion, and luteal function(Kansas Agricultural Experiment Station, 2011-08-02) Stevenson, Jeffrey S.; Mee, M. O.; Call, Edward P.; jss; epcallAdministering saline to 14 repeat breeders or 100 μg GnRH to 38 repeat breeders resulted in a greater (P=.07) proportion of pregnancies at 42 to 56 days after third service and fewer (P<.05) lost pregnancies during the 25- to 38-day period of placentation. Concentrations of LH in serum of six repeat breeders previously given 100 μg GnRH 12 hr after detected estrus (day 0) were reduced (P<.05) on days 1, 3, and 8 after estrus compared to those in six cows previously given saline at estrus. Concentrations of FSH were similar among treatment groups on days 1 and 3, but were elevated (P<.05) on day 8 in GnRHtreated cows. Furthermore, all six GnRH-treated cows had detectable FSH pulses on day 8 compared to two of six control cows. Concentrations of progesterone in serum were elevated (P<.05) on days 8 to 10 after estrus in GnRH-treated cows, and their corpora lutea obtained on day 10 after estrus and treatment contained a greater (P<.05) proportion (31 vs. 14%) of large-diameter (21 to 37 μm) luteal cells and a lesser (P<.05) proportion (69 vs. 86%) of small-diameter (10 to 17 μm) luteal cells than corpora lutea from control cows. In vitro production of progesterone in response to LH was reduced (P<.05) in luteal tissue obtained on day 10 after estrus from cows previously treated with GnRH at estrus compared to cows given only saline. It appears that pregnancy rates are improved in repeat breeders given GnRH at the time of insemination as a result of increased secretion of progesterone related to alterations in the morphology and function of the corpus luteum, as well as possible influences of FSH secretion from the pituitary gland.
