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Biomedical subjects

K R Simmons

Publications and source records attributed to K R Simmons.

11 recordsLinked to original sources
PubMed1989

Collection of blood-engorged black flies (Diptera: Simuliidae) and identification of their source of blood.

Blood-engorged black flies were captured by 2 methods: early morning application of a quick knock down insecticide (resmethrin) into tree canopies, and late afternoon to early evening truck trapping. More engorged flies were captured per man-hour with the tree spraying method than with the truck trap. The percentages of females captured by the spraying and truck trap methods that were engorged were 18 and 1.3, respectively. The most commonly engorged species captured were Prosimulium magnum and P. mixtum/fuscum, and Simulium jenningsi and S. venustum (70% of total). Blood sources of 12 black fly species were identified. Mammals comprised 95% of the blood sources identified. The most common hosts were equines (31%), bovines (25%) and raccoons (19%). Seven percent of all meals identified were from mixed sources, of which 43% involved both mammals and birds.

Animals↗
PubMed1986

Synchronization of estrus in dairy cows with prostaglandin F2 alpha and estradiol benzoate.

A field study using 322 lactating dairy cows in seven commercial and two university herds was conducted to determine if treatment with estradiol benzoate 40 to 48 h after treatment with prostaglandin F2 alpha would enhance synchronization of estrus. Estrogen treatment tended to increase the proportion of cows in estrus within 5 d (synchronized) after prostaglandin treatment (66.9% versus 58.9%). Of synchronized cows, a greater proportion treated with estrogen (66.9%) were in estrus on d 3 than those not receiving estrogen (48.2%). First service conception rate (31.9%) and interval to second service (35.6 d) were not affected by treatment with estrogen. Milk progesterone was measured in university herds. More cows with milk progesterone concentrations greater than or equal to 8 ng/ml were synchronized (75.4%) than those with less than 8 ng/ml (63.3%). Treatment with estrogen increased synchrony of cows with high progesterone (90.3%) more than prostaglandin alone (60.0%). Based on progesterone concentrations at breeding and 22 to 24 d later, estimated conception rate was 58.7%, and net conception rate based on palpation was 41.3%. Tighter synchrony of estrus can be achieved by using estradiol benzoate 40 to 48 h after prostaglandin. Concentrations of milk progesterone might predict success of treatment.

Animals↗
PubMed1979

Prostaglandin in milk, days open, and estrus detection in dairy cows treated with prostaglandin F2 alpha.

Prostaglandin F2 alpha was used to induce estrus in postpartum dairy cows to decrease calving interval and time spent on heat checks. The amount of prostaglandin residue in milk after treatment also was investigated. Twenty-two control cows, checked for heat twice daily, were bred at estrus after 55 days postpartum. Sixty-three cows checked on days 55 to 60 were either bred if in estrus or treated with 30 mg of prostaglandin F2 alpha injected intramuscularly on day 60 and bred at induced estrus or at 75 h posttreatment. Twelve cows were in heat between days 55 and 60 and were bred. Twenty-nine of 51 treated cows were seen in estrus; all of these were bred and 51.7% conceived at this time. Treated cows had fewer days to first service than did controls, but days open were not different, 105.7 versus 101.8. Fertility was similar. Controls required more heat checks than did treated cows (39 to 8.2). Milk from 17 cows at two milkings before and ten milkings after treatment had similar concentrations of prostaglandin (698 +/- 27 pg/ml) except for the first posttreatment milking when prostaglandin concentration almost doubled (1.293 +/- 143 pg/ml).

Animals↗