Supplemental dietary protein for grazing dairy cows: reproduction, condition loss, plasma metabolites, and insulin.

An experiment was conducted over a 2-yr period to investigate the influence of grain crude protein (CP) and rumen undegradable protein (RUP) concentration on reproduction and energy status of dairy cows grazing annual ryegrass (Lolium multiflorum) and oats (Avena sativa). Holstein cows (n = 122) were blocked by calving group [partum (0 d postpartum) vs. postpartum (41 +/- 19 d postpartum at study initiation)] and assigned to grain supplements containing high CP [22.8% of dry matter (DM)], moderate CP (16.6%), or moderate CP (16.2%)] supplemented with RUP from blood meal and corn gluten meal. Postpartum condition loss was greater and first-service pregnancy rate was lower for partum-group cows receiving high CP grain supplements compared with control cows receiving moderate CP supplements. The RUP supplements reduced grain consumption, increased days to first estrus, and reduced first-service pregnancy rate of partum-group cows. The reproduction of postpartum group cows was unaffected by protein supplements. Plasma urea nitrogen was higher for cows fed high CP diets, but plasma ammonia nitrogen, glycated hemoglobin, nonesterified fatty acids, beta-hydoxybutyrate, glucose, and insulin concentrations were similar to cows fed moderate CP. Excess postpartum condition loss, coupled with inconsistent protein supplement effects on days to first service and first-service pregnancy rate, suggest that energy deprivation may have contributed to the low fertility experienced by grazing cows in this study.

Clinical relative biological effectiveness of low-energy x-rays emitted by miniature x-ray devices.

Several groups are developing ultra-miniature x-ray machines for clinical use in radiation therapy. Current systems are for interstitial radiosurgery and for intravascular insertion for irradiation to prevent re-stenosis. Typical generating voltages are low, in the 20 to 40 kV range. It is well established that the biological effectiveness of such low-energy photons is large compared with higher-energy gamma rays, because of the dominance of photoelectric absorption at low energies. We have used microdosimetric analyses to estimate RBEs for such devices, both at low doses and clinically relevant doses, relative to radiations from 60Co, 192Ir, 125I and 90Sr/90Y. The RBEs at clinically relevant doses and dose rates for these low-energy x-ray sources are considerably above unity, both relative to 60Co and to 192Ir photons, and also relative to 125I and 90Sr/90Y brachytherapy sources. As a function of depth, the overall effect of the change in dose and the change in beam spectrum results in beams whose biologically weighted dose (dose x RBE) decreases with depth somewhat more slowly than does the physical dose. The estimated clinically relevant RBEs are sufficiently large that they should be taken into account during the treatment design stage.

Crude protein and rumen undergradable protein effects on reproduction and lactation performance of Holstein cows.

We conducted a study to determine the effects of excess dietary crude protein (CP) and rumen undegradable protein (RUP) on reproduction and lactation performance of Holstein cows. During each of three yearly replicates, cows were blocked by previous mature equivalent milk production and randomly assigned at calving (n = 47; partum group) or at 42 +/- 21 d postpartum (n = 134; postpartum group) to the following dietary treatments: 1) ryegrass pasture supplemented with a corn and soybean meal grain mix (high CP, moderate RUP); 2) ryegrass pasture mornings and corn silage evenings, supplemented with grain as in diet 1 (moderate CP, moderate RUP control diet), and 3) ryegrass pasture mornings and corn silage evenings, supplemented with a grain mix containing corn, soybean meal, corn gluten meal, and blood meal (moderate CP, high RUP). Dietary CP and RUP concentrations were approximately 23.1, 5.8; 17.7, 5.0; and 17.2, 6.8% of dry matter for diets 1 to 3, respectively. Plasma urea N concentrations were highest in cows fed diet 1 (25.0 mg/dl), intermediate in cows on diet 2 (20.1 mg/dl), and lowest in cows on diet 3 (18.5 mg/dl). Cows fed excess dietary protein (diet 1) exhibited lower first breeding pregnancy rates (24.1 vs. 41.0%) and lower overall pregnancy rates (53.4 vs. 75.4%) than did cows fed diet 2, increasing time nonpregnant by an average of 15.1 d per cow. Reproductive performance was similar between cows fed diets 2 and 3. Mean fat-corrected milk (FCM) yield was not affected by protein concentration (diet 1 vs. 2); however, partum group cows that received supplemental RUP (diet 3) produced more 3.5% FCM than controls in early lactation. Feeding grain diets that contained excess dietary protein impaired the reproductive performance of dairy cows grazing ryegrass.

Cavernous hemangioma of the lung in an infant.

A 10-week-old male was found to have a cavernous hemangioma in the right lower pulmonary lobe. Hemangiomas of the lung are infrequent and in pediatric patients exceptionally rare. This may explain why, among the catalogs of intrapulmonary cystic lesions in children, cavernous hemangioma is a conspicuously absent entity and is rarely imagined in the clinical differential diagnosis. We present one such case, establish its distinction from arteriovenous malformations, and briefly review the available literature.

Gonadotropin releasing hormone therapy in functional infertility of dairy cattle.

Effects of gonadotropin-releasing hormone (GnRH) on conception rate was tested in 379 repeat-breeders in nine large dairy herds in Louisiana. Cattle with three or more services were treated intramuscularly with GnRH at the time of artificial insemination. The conception rate for the repeat-breeders treated with GnRH was significantly greater than for the controls (56 vs 40%). Furthermore, repeat-breeders that were treated with GnRH for two consecutive times at insemination resulted in a 53% increase in conception rate over the controls.

Elevation of intraocular pressure by calcium channel blockers.

Topical administration of three different calcium channel blockers (verapamil hydrochloride, diltiazem hydrochloride, or nifedipine) increased intraocular pressure transiently in rabbits. Outflow facility and episcleral venous pressure were unchanged. Aqueous humor flow seemed to be increased 30 minutes after topical application of verapamil when estimated by the Goldmann equation or by changes in anterior chamber fluorescein-labeled dextran concentration. However, aqueous humor ascorbate concentrations and turnover of radioactive iodide did not differ from that in the untreated eye. Ocular blood volume was found to be increased after topical application of verapamil, which suggested vascular changes as a possible mechanism for the induced increase in IOP. Topical verapamil raised IOP in healthy human volunteers, but the elevation was less than observed in rabbits. Single oral doses of verapamil in rabbits or human beings had no effect on IOP.

The effects of body immersion on aqueous humor dynamics in rabbits.

Rabbits subjected to free-floating body immersion demonstrated decreases in intraocular pressure followed by later increases. These intraocular pressure alterations were associated with parallel changes in aqueous humor production. Episcleral venous pressure was elevated during immersion but outflow facility was unaltered. The decrease in intraocular pressure could be partially blocked by pretreatment with vasopressin or desoxycorticosterone acetate. In cross-circulation studies between an immersed and non-immersed rabbit, a decrease in intraocular pressure was observed in both animals. This observation further supported the involvement of humoral factors in the body-immersion induced intraocular pressure response.

Effect of temperature-season on bovine adrenal cortical function, blood cell profile, and milk production.

Data collected monthly for one calendar year from Holstein cows lactating under Louisiana ambient climatic conditions comprised a total of 264 cow-months. The year was divided into seasons of cool, intermediate, and hot temperatures. The hot season elicited depressions in circulating corticoids and percent hematocrit. Leukocytosis was a response to increasing ambient temperature primarily accounted for by an increase in circulating neutrophils. Progression from intermediate to hot season gave evidence of eosinophila, and in addition, a relative eosinopenia may have been induced by increased adrenal cortex activity. Milk production was depressed during the hot temperature-season and showed no significant relationship with corticoids of plasma. Rectal temperatures and respiration rates were indicative of heat stress in the hot temperature-season and gave significant negative correlations with circulating corticoid concentration.

Routine postpartum treatment of dairy cattle with intrauterine neomycin sulfate boluses.

Within location, 119 dairy cattle from two experiment station herds, which had no problems associated with parturition, were randomly either treated by insertion of two intrauterine boluses containing a total of 1000 mg neomycin sulfate 24 h postpartum or maintained as a control. Uteri and ovaries of all cows were palpated 17 to 24 days postpartum and at 14 day intervals thereafter until inovulation of the uterus was judged complete and an estrus had been observed. All cows were inseminated at the first estrus after 60 days postpartum and at each estrus thereafter until conception. Cows treated with neomycin sulfate required more services per conception (1.7 to 1.4) and were open more days before conception (100.5 to 88.5) than the controls. The probable cause of the lowered reproductive efficiency is discussed. Treatment did not later significantly days to ovulation, estrus, involution, or first service. Three treated and five control animals needed additional uterine treatment. Routine intrauterine treatment of all cows with neomycin sulfate boluses should not be recommended.