Biomedical subjects

J B Stone

Publications and source records attributed to J B Stone.

12 recordsLinked to original sources

PubMed1986

Reproductive performance of lactating Holstein cows fed supplemental beta-carotene.

Fifty-six Holstein cows were used in a replicated study to determine whether supplemental beta-carotene improved reproductive performance. Each of two replicates was of completely randomized design with 2 X 2 factorial arrangement of two diets with or without beta-carotene supplementation. On a dry matter basis, diet 1 was 5% hay, 20% haylage, 25% corn silage, and 50% concentrate. Diet 2 was 7.5% hay, 42.5% corn silage, and 50% concentrate. The diets contained adequate amount of vitamins A, D, and E. From 10 d postpartum until pregnancy was confirmed by rectal palpation, half the cows on each diet received a supplement of 400 mg beta-carotene per head daily. The remaining cows on each diet received a supplement of 160,000 IU vitamin A per head daily. Supplemental beta-carotene increased plasma beta-carotene throughout the trials. Median days to first ovulation, first service, days open, and mean services per conception were: 22, 77, 97, and 1.6 for cows receiving beta-carotene supplement compared with 19.5, 73, 82, and 1.9 in controls. Supplementation did not affect first service conception rate, uterine involution, or milk yield. Incidence of follicular cysts, luteal cysts, pyometra, and endometritis in cows fed beta-carotene were 11, 7, 0, and 7% compared with 8, 21, 4, and 13% in control cows. Supplemental beta-carotene did not improve the fertility of Holstein cows.

Animals↗

PubMed1986

Effect of prepartum energy, body condition, and sodium bicarbonate on production of cows in early lactation.

In trial 1, the effects of dietary energy (102, 131 or 162% of requirement) in the dry period and of sodium bicarbonate (0 or .75% of diet dry matter) in early lactation were assessed with 31 cows in a 3 X 2 factorial arrangement of treatments. Body condition and weight increased linearly with prepartum energy. Dry matter intake and milk yield were similar across treatments through 12 wk postpartum. Sodium bicarbonate increased milk fat content only in the 131% group, an effect apparently related to greater mobilization of fat in that group. In trial 2, energy treatments imposed in late lactation (145 to 55 d prepartum) and in the dry period (55 to 0 d) were 1) cows fed to requirement in both periods, 2) cows overfed in the first and underfed in the second period, 3) cows fed to requirement in the first and overfed in the second period, and 4) cows overfed in both periods. Cows in treatments 1 and 2 (normal) calved in a thinner state than those in 3 or 4 (fat). In the first 12 wk postpartum, intake did not differ, but cows in groups 3 and 4 produced more milk. Sodium bicarbonate imposed factorially postpartum increased milk fat content. Overconsumption of energy prepartum did not impair production when high energy total mixed rations were fed postpartum.

Animals↗

PubMed1986

The relationship among current management systems, production, disease and drug usage on Ontario dairy farms.

The study involved 110 randomly selected dairy farms located in the Ontario, Canada counties of Bruce, Grey, Huron, Oxford, Perth, Waterloo and Wellington. Herds were classified as "intensive" and "extensive". On extensive farms, data were collected at the herd level only, while on intensive farms, data were recorded at both the individual animal and herd level. Data collection continued for approximately two and one-half years. At each visit, technicians collected production data from the most recent production recording scheme report and from the "daily log" maintained by each producer. As well as the ongoing data collection procedures, a number of supplementary data collections were made. The average 305 day milk production increased gradually during the three calendar years from 6224.6 kg in 1981 to 6443.7 kg in 1983. The average calving interval was stable at 13.2 months for all three years. The majority of cows removed from the herds were culled for beef (0.243 per animal year). The next highest removal rate was for domestic sale, followed by death, export sale and destroyed. The highest disease rate, for those conditions whose rates were based on calving, was for retained placenta (0.09 per calving), while clinical mastitis was highest for those conditions whose rates were based on animal years (0.37 per animal year). The overall crude antimicrobial dosage rate, that is, including any antimicrobial used for either prophylactic or therapeutic purposes, was 3.85 doses per animal year. The rate for therapeutic purposes only was 3.6 doses per animal year. Penicillin/streptomycin was used most often with a rate of 1.45 doses per animal year.

Agriculture↗

PubMed1985

Effect of protein on growth of Holstein heifer calves from 2 to 10 months.

Two trials involving 44 weaned Holstein heifer calves were to determine effects of protein on growth in weight and wither height, dry matter intake, and digestibility. In trial 1, 24 calves were fed according to requirements from 85 to 182 d of age, then at 80, 100, or 120% of recommended amounts for dietary protein content until 295 d. Weight at 295 d increased linearly with protein (280, 287, 298 kg), but wither height and dry matter intake were unaffected. In trial 2, 20 calves were fed 80, 100, or 120% of recommended protein from 71 to 182 d. Weight and wither height at 182 d responded quadratically to protein with highest values from the medium protein diet. From 183 to 295 d, trial 2 calves were rerandomized to diets of medium or high protein. Weight at 295 d was increased by high protein. An interaction between treatments for wither height indicated responses to high protein after 182 d for calves on low or medium protein before that time and a decrease for calves on high protein throughout. In male calves of similar age, elevated protein increased apparent protein digestibility but had inconsistent effects on digestibility of dry matter. Current protein recommendations appear adequate for calves to 6 mo of age but thereafter may be too generous.

Animals↗

PubMed1979

The rates and patterns of survivorship and disease in a university dairy herd.

The rates and patterns of disease occurrence and survivorship were determined over a six year period in a university operated dairy herd. Of the ten diseases selected for study, clinical mastitis occurred most frequently with an incidence rate of 10.1% and displaced abomasum occurred least frequently with an incidence rate of 4.4%. The occurrence of all disease except those of the ovary was associated with the age of the cow. Mastitis, pneumonia and cystic graafian follicles tended to reoccur in the same cow after the initial occurrence. The average culling rate was 25.6% and the median number of years cows survived in the herd was 3.4 years. Methods for calculating the various rates and survivorship are described and their interpretation discussed.

Animals↗

PubMed1979

The association between disease, production and culling in a university dairy herd.

The impact of ten diseases of dairy cattle on milk production, calving interval and culling were studied in a university operated dairy herd. Cows with clinical mastitis, ketosis or displaced abomasum had lowered milk production. Cows with metritis, retained placenta, cystic graafian follicles or ovarian hypofunction had longer calving intervals. Cows with clinical mastitis, metritis, pneumonia or retained placenta had increased risks of culling. The relationship between disease and culling was based on the medical history of culled and nonculled cows using a case control approach. Therefore, it is likely that in many cases, the association between disease and culling is due to the impact of that disease on productivity.

Animals↗

PubMed1975

Glucose metabolism in cows fed low- and high-roughage diets.

Six lactating first-calf Holstein cows were used to test the effect of dietary roughage on glucose metabolism. Cows were fed either a low-roughage or high-roughage diet at isocaloric digestible energy intakes in a double changeover design experiment. Mean values (plus or minus standard deviation) for milk yield (kg/day), fat (%), lactose (%), and protein (%) for cows fed low-roughage were 19.0 plus or minus 4.4, 3.11 plus or minus .78, 5.19 plus or minus .27, 3.44 plus or minus .48; values for cows fed high-roughage were 17.5 plus or minus 5.1, 3.99 plus or minus .58, 4.94 plus or minus .25, and 2.78 plus or minus .33. One hour post-feeding on the 20th day of each period 2 mCi of tritiated glucose were administered to each cow by single injection to measure glucose kinetics. Mean values (plus or minus standard deviation) for plasma concentration (mg/100 ml) pool size (mg/kg), half-time (min), and utilization rate (mg/kg--75 per min) of glucose, and plasma insulin concentration (muU/ml) for cows fed low-roughage were 63.1 plus or minus 3.9, 17.9 plus or minus 3.4, 30.4 plus or minus 5.2, 8.55 plus or minus 2.44, and 22.0 plus or minus 3.9; for cows fed high-roughage values were 54.9 plus or minus 2.2, 114.5 plus or minus 17.2, 40.0 plus or minus 2.2, 4.06 plus or minus .38, and 16.2 plus or minus 2.4. A glucose load was administered intravenously to each cow on the last day of each period. Glucose half-times and mean plasma insulin following the clearance test were not affected by diet. Compared to high-roughage, low-roughage diets greatly affect metabolism in lactating cows when isocaloric intakes of each are fed. Fat depression, however, may or may not occur simultaneously.

Animal Feed↗

PubMed1971