Fertility in heifers and cows after low dose insemination with sex-sorted and non-sorted sperm under field conditions.

The present study was performed to test fertility after low dose insemination with sexed and non-sexed sperm in dairy cattle under field conditions in Switzerland. Spermatozoa were stained with Hoechst 33342 and sorted by flow cytometry. A total of 132 heifers and cows were inseminated with 2 x 10(6) X-bearing, frozen-thawed sperm (A) and 91 animals were inseminated with the same dose using non-sorted, frozen-thawed sperm (B). Pregnancy examination by ultrasound was performed twice, 30-40 days (PE1) and 70-90 days (PE2) after insemination. The pregnancy rates after PE1 were 33.3% (9/27) and 59.3% (16/27) in heifers (P=0.05) and 27.6% (29/105) and 28.1% (18/64) in cows (P>0.05) for groups A and B, respectively. Embryonic losses between PE1 and PE2 in heifers were 11.1% (1/9) and 0% (0/16) and in cows 17.2% (5/29) and 5.6% (1/18), the differences between groups A and B not being significant (P>0.05). Calving rates in heifers were 29.6% (8/27) and 57.8% (15/26), whereas in cows 22.1% (23/104) and 23.4% (16/63) gave birth to calves (for both groups P>0.05). The sex ratio was different (P<0.05) between A (85.3%) and B (58.6%). From our results it can be concluded that conception rates of sorted and non-sorted semen are similar using an insemination dose of 2 x 10(6). Fertility may be increased by improving sexing technology and animal management.

An immunochemical assay to detect DNA damage in bovine sperm.

An immunochemical assay has been developed to detect oxidative damage in bovine sperm DNA. Sperm DNA contains a large amount of oxidative damage as a result of exposure to exogenous agents, but damage also can caused by normal metabolic processes and the absence of DNA repair in the later stages of spermatogenesis. A freeze-thaw procedure performed on extended bovine sperm in straws did not induce additional DNA damage immediately after thawing compared with nonfrozen extended sperm. The data suggest that the amount of oxidative damage correlated to the percentage of artificially inseminated cows returning to service within 56 days postinsemination, because a number of sires with high sperm concentrations had a large variation in fertility after artificial insemination. These observations have led to the conclusion that by measuring DNA damage in thawed sperm, one might predict the fertility of bulls with high semen concentration.

[Veterinary supervision of dairy facilities in the Netherlands: what do veterinarians think about participating and non-participating cattle owners?]. / Veterinaire begeleiding van melkveebedrijven in nederland: hoe denkt de dierenarts over deelnemende en niet-deelnemende veehouders?

Dairy herd health and production management programmes are being used increasingly more often, also in the Netherlands. However, little is known about the rationale behind the farmers' decision to participate or not to participate. This paper reports the results of a questionnaire survey among cattle practitioners about why they thought farmers did or did not participate in these programmes, the perceived advantages and disadvantages of such programmes, the extent to which the respective farming areas were represented in the programmes, and the reasons why farmers stopped participation in the programme. Furthermore, the ways in which the practitioners try to convince the non-participating farmers to join the programme were addressed. The future of dairy herd health programmes in the context of quality assurance programmes and the way the farmers think about these developments were discussed by the practitioners.

Long-term trends in sperm counts of dairy bulls.

A possible decline in sperm counts in men and its potential relation to exposure to environmental contaminants are subjects of a broad discussion. Whereas data for human research in this area are limited, records over prolonged periods on sperm counts in dairy bulls are amply available and provide useful information. Therefore, 75,238 ejaculates collected between 1977 and 1996 from 2,314 bulls at Noordwest, a center for artificial insemination (AI) in the Netherlands, were used to evaluate long-term trends in sperm output. Data were adjusted for known effects, of which age was the most important, followed by interval between semen collections, breed and season of collection. Mean sperm output per year of collection from 1978 through 1996 varied between 6.2 x 10(9) and 9.5 x 10(9) without any long-term decline. Mean sperm output per year of birth from 1970 through 1995 showed less variation, between 6.7 x 10(9) and 9.0 x 10(9), also without any long-term decline. Earlier published data of 22,120 ejaculates of 3,030 bulls of the same region, tested between 1962 and 1977, showed a corresponding sperm output, confirming the absence of any decline. The unaffected sperm output in bulls in the Netherlands during the last decades in spite of exposure to pesticides and other polychlorinated organic compounds, the type of environmental contaminants under discussion, is a positive signal, although a complete extrapolation to the human situation remains difficult.

Estimating length of survival in end-stage cancer: a review of the literature.

Accurately estimating survival times in patients with end-stage cancer is on ongoing challenge for palliative care clinicians. Psychosocial as well as physiological factors have been thought to influence the length of the terminal phase of illness, but conclusive findings remain elusive. This review examines the studies that have addressed the issue using observable, measurable criteria associated with physiological, clinical status. Improving the ability to estimate accurately a patient's length of survival may improve patient/family quality of life and assist in the efficient, appropriate use of resources. Additional research in this and other palliative care issues will need to be better funded and organized if progress is to be made.

Identity and paternity testing of cattle: application of a deoxyribonucleic acid profiling protocol.

We have applied DNA profiling for identity and parentage studies of cattle using a standardized procedure based on synthetic micro- and minisatellite multilocus core probes in Southern blot hybridization assays. This protocol is useful for paternity analysis of cattle and for real case work (e.g., identity and paternity disputes).