scholarly journals Morphological evaluation of bovine embryos recovered non-surgically from superovulated dairy cows on days 6 1/2 to 7 1/2 : A field study

1979 ◽  
Vol 19 (5) ◽  
pp. 1599-1611 ◽  
Author(s):  
T. GREVE ◽  
H. LEHN-JENSEN ◽  
N. O. RASBECH
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Bovine Embryos ◽  
Morphological Evaluation

scholarly journals Factors Affecting Milk Flow Traits in Dairy Cows: Results of a Field Study

2007 ◽  
Vol 90 (3) ◽  
pp. 1159-1167 ◽  
Author(s):  
A. Sandrucci ◽  
A. Tamburini ◽  
L. Bava ◽  
M. Zucali
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Factors Affecting ◽  
Milk Flow

Embryonic disc development and subsequent viability of cattle embryos following culture in two media under two oxygen concentrations

2004 ◽  
Vol 16 (8) ◽  
pp. 787 ◽  
Author(s):  
A. E. Fischer-Brown ◽  
B. R. Lindsey ◽  
F. A. Ireland ◽  
D. L. Northey ◽  
R. L. Monson ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Latin Square ◽  
Bovine Embryos ◽  
Morphological Evaluation ◽  
Embryonic Disc ◽  
Developmental Capacity ◽  
Series Of Experiments ◽  
Oxygen Concentrations

Bovine embryos were produced in vitro using a 2 × 2 design of modified medium (KSOM or SOF) and oxygen concentration (5% or 20%). Day 7 blastocysts were transferred in bulk (n = 11, on average) to recipient heifers and recovered non-surgically at Day 14. In two replications of a Latin square, eight heifers received embryos from each combination of factors. Recovered embryos were evaluated for trophoblast length and width, as well as the presence and diameter of an embryonic disc (ED). An ED was detected in a higher percentage of embryos that had been cultured in KSOM than SOF (72% v. 46%, respectively; P < 0.05). The aim of a second series of experiments was to associate Day 14 morphology with subsequent developmental capacity. In vitro-produced blastocysts were transferred (n = 17–20) on Day 7 to each of eight heifers and recovered at Day 14. Thirty-eight blastocysts were retransferred to heifers following morphological evaluation. Embryos in which an ED with no signs of degeneration had been detected maintained more pregnancies than other embryos in which an ED had either shown signs of degeneration or had not been detected (5/8 v. 2/30, respectively; P < 0.01). Further investigation into ED integrity at the elongating stage may contribute to our understanding of pregnancy establishment and maintenance.

Transmission and quantification of verocytotoxin-producingEscherichia coliO157 in dairy cattle and calves

2008 ◽  
Vol 137 (1) ◽  
pp. 114-123 ◽  
Author(s):  
J. M. SCHOUTEN ◽  
E. A. M. GRAAT ◽  
K. FRANKENA ◽  
F. VAN ZIJDERVELD ◽  
M. C. M. DE JONG
Keyword(s):  
Escherichia Coli ◽  
Dairy Cows ◽  
Field Study ◽  
Dairy Herd ◽  
Infectious Period ◽  
Basic Reproduction Ratio ◽  
Transmission Experiment ◽  
Reproduction Ratio ◽  
Susceptible Population ◽  
Previous Summer

SUMMARYData from a field study of 14 months duration in a naturally colonized dairy herd and data from an experiment with calves were used to quantify transmission of verocytotoxin-producingEscherichia coli(VTEC O157) in cattle. For the latter, two groups of 10 calves were randomly assigned and put out in one of two pastures. From each group, five animals were experimentally inoculated with 109c.f.u. O157 VTEC and, considered infectious, put back in their group. Each of the susceptible contact calves became positive within 6 days of being reunited. The estimate of the basic reproduction ratio (R0) in the experiment was 7·3 (95% CI 3·92–11·5), indicating that each infectious calf will infect seven other calves on average during an assumed infectious period of 28 days in a fully susceptible population. TheR0among dairy cows appeared to be about 10 times lower (0·70, 95% CI 0·48–1·04). After the transmission experiment, six contact-infected animals that were shedding continuously during the experiment were housed in a tie stall during winter. After 40 days, all six tested negative for O157 VTEC. In June, after a period of 34 weeks in which the heifers remained negative, they were put out in a clean and isolated pasture to observe whether they started shedding again. On each pasture that was infected with O157 VTEC during the transmission experiment the previous summer, newly purchased susceptible calves were placed. None of the heifers or calves started shedding during 14 weeks, indicating that both the heifers and the previously contaminated pasture did not function as reservoir of O157 VTEC.

scholarly journals Efficacy of Levamisol® on Milk Production of Dairy Cows: A Field Study

1987 ◽  
Vol 70 (5) ◽  
pp. 1080-1085 ◽  
Author(s):  
Elliot Block ◽  
W.A. McDonald ◽  
B.A. Jackson
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Milk Production

scholarly journals Low cortisol levels in blood from dairy cows with ketosis: a field study

2010 ◽  
Vol 52 (1) ◽  
Author(s):  
Kristina B Forslund ◽  
Örjan A Ljungvall ◽  
Bernt V Jones
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Cortisol Levels ◽  
Low Cortisol

142 EFFECT OF GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND INSULIN-LIKE GROWTH FACTOR-1 ON DEVELOPMENT AND POST-TRANSFER SURVIVAL OF BOVINE EMBRYOS PRODUCED IN VITRO

2009 ◽  
Vol 21 (1) ◽  
pp. 170 ◽  
Author(s):  
B. Loureiro ◽  
L. Bonilla ◽  
J. Block ◽  
J. M. Fear ◽  
A. Q. Bonilla ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Colony Stimulating Factor ◽  
Bovine Embryos ◽  
Gm Csf ◽  
Lactating Dairy Cows ◽  
Macrophage Colony Stimulating Factor ◽  
Calving Rate ◽  
Macrophage Colony ◽  
Stimulating Factor

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multifunctional cytokine that has been implicated in the regulation of preimplantation embryonic development in several species. Insulin-like growth factor-1 (IGF-1) can increase the proportion of bovine embryos that develop to the blastocyst stage and increase embryo survival following transfer to heat-stressed, lactating dairy cows (Block J et al. 2003 J. Anim. Sci. 81, 1590–1602; Theriogenology 67, 1518–1529). The current objective was to test whether addition of GM-CSF and IGF-1 to culture medium enhances development and post-transfer survival of in vitro-produced bovine embryos. Holstein COC shipped overnight in a portable incubator in oocyte maturation medium were fertilized with X-chromosome selected sperm from Holstein bulls. X-selected sperm were used because females were preferred. Morulae and blastocysts were collected at Day 7 after insemination and transferred at Day 7 after ovulation to lactating dairy cows subjected to a modified OvSynch protocol. In Experiment 1, conducted from June 29 to August 31, embryos were cultured in KSOM-BE2 alone, KSOM-BE2 with 100 ng mL–1 of Arg3-IGF-1 or KSOM-BE2 with 10 ng mL–1 of recombinant BoGM-CSF. Treatments were added at Day 1 after insemination. As compared to control embryos (17 ± 2%), the percentage of cleaved embryos that became transferable morulae or blastocysts at Day 7 was increased (P < 0.05) by GM-CSF (25 ± 2%) but not by Arg3-IGF-1 (18 ± 2%). There was no significant effect of treatment on pregnancy rate at Day 30 to 35 [34% (n = 52), 35% (n = 51), and 43% (n = 55) for control, GM-CSF, and IGF-1, respectively] or calving rate (27, 35, and 40%) although values were numerically greater for cows receiving IGF-1 treated embryos. In experiment 2, conducted from September 7 to February 1, embryos were cultured in KSOM-BE2 alone, KSOM-BE2 with 100 ng mL–1 Arg3-IGF-1 added at Day 1 after insemination, or KSOM-BE2 with 10 ng mL–1 recombinant BoGM-CSF added at Day 5 after insemination. GM-CSF, but not IGF-1, increased the percentage of oocytes (P < 0.03) and the percentage of cleaved embryos (P = 0.05) that became transferable morulae or blastocysts at Day 7. The percentage of cleaved embryos becoming blastocysts was 14 ± 1% for GM-CSF, 14 ± 2% for Arg3-IGF-1 (P = 0.11), and 10 ± 1% for controls. Treatment with GM-CSF increased (P = 0.056) the percentage of cows pregnant at Day 30 to 35 [34% (n = 79), 43% (n = 107), and 27% (n = 44) for control, GM-CSF, and IGF-1, respectively]. Data on calving rate are currently being collected; to date, 86% of calves were female. Results indicate that embryo competence for post-transfer survival can be enhanced by treatment with GM-CSF at Day 5 after fertilization. Research supported by USDA Grant 2006-55203-17390, BARD Grant US-3986-07 and the Southeast Milk Dairy Checkoff Program. B.L. was supported by a CAPES (Brazil)/Fulbright Fellowship.

scholarly journals A randomized herd-level field study of dietary interactions with monensin on milk fat percentage in dairy cows

2009 ◽  
Vol 92 (2) ◽  
pp. 777-781 ◽  
Author(s):  
J. Dubuc ◽  
D. DuTremblay ◽  
M. Brodeur ◽  
T. Duffield ◽  
R. Bagg ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Milk Fat ◽  
Fat Percentage ◽  
Herd Level ◽  
Dietary Interactions

scholarly journals In vitro production of embryos from high performance cows and the development of frozen-thawed embryos after transfer: a field study

2008 ◽  
Vol 53 (No. 7) ◽  
pp. 358-364 ◽  
Author(s):  
M. Machatkova ◽  
P. Hulinska ◽  
Z. Reckova ◽  
K. Hanzalova ◽  
J. Spanihelova ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Field Study ◽  
Growth Phase ◽  
High Performance ◽  
Follicular Development ◽  
The Mean ◽  
The Difference ◽  
Fresh Embryos ◽  
Holstein Dairy Cows

In this field study, embryos were derived from genetically highly valuable cows excluded from breeding due to reproductive disorders. Cows, 5 to 10 years old, of Czech Siemmental, Holstein Dairy and Beef Cattle breeds were used as oocyte donors. Oocytes were obtained either in the growth phase of the first follicular wave from cows with synchronized oestrus or in any other phases of follicular development from cows without oestrus synchronization. The embryos were prepared by a standard protocol described previously. The mean number of usable oocytes, transferable and freezable embryos per donor, and the mean percentage of usable, transferable and freezable embryos were assessed. The results were analyzed by Student’s-<I>t</I> and Chi-squared tests. The embryos were frozen according to a slow freezing protocol. After thawing, they were transferred to recipients on Day 7 after oestrus. Irrespective of the breed, the mean numbers of usable oocytes and transferable and freezable embryos collected per donor were significantly higher (<I>P</I> < 0.01) for the synchronized than for the nonsynchronized donors (20.4 vs 11.7, 4.3 vs 1.0 and 3.2 vs 0.8, respectively). Similarly, the mean percentages of usable oocytes, transferable and freezable embryos were significantly higher (<I>P</I> < 0.01) for the synchronized than for the nonsynchronized donors (28.5% vs 20.5%, 20.9% vs 9.0% and 15.8% vs 6.5%, respectively). On comparison of the synchronized and nonsynchronized donors of each breed, the difference in the mean percentage of usable oocytes was significant (<I>P</I> < 0.01) in cows of all three breeds, the difference in the mean percentage of transferable embryos was significant in Czech Siemmental and Holstein Dairy cows (<I>P</I> < 0.01) and the difference in the mean percentage of freezable embryos was significant only in Holstein Dairy cows (P < 0.01). After the transfer of 41 frozen-thawed embryos and 43 fresh embryos, 20 heifers and 24 heifers became pregnant, respectively. In conclusion: (a) higher number of oocytes from infertile, genetically valuable cows was recovered in the growth phase compared with the other phases of follicular development; (b) greater development of these oocytes resulted in more embryos for transfer and cryopreservation; (c) the transfer of frozen-thawed and fresh embryos resulted in pregnancy rates of 48.8% and 55.8% , respectively.

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