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- Author or Editor: Annette Liesegang x
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Abstract
Objective
To determine the effect of feeding frequency and cow-specific factors on diurnal variations of blood metabolites concentrations.
Animals
40 dairy cows from 2 herds.
Procedure
Each herd was fed concentrate at a specific feeding frequency (automatic vs twice daily). Blood samples were collected 4 times daily. Plasma concentrations of glucose, nonesterified fatty acids (NEFA), and β-hydroxybutyrate (BHBA) were analyzed, and concentrations of urea, cholesterol, and total protein (TP) were determined in serum samples. A multivariate repeated-measures ANOVA was used to test the effect of time, feeding frequency, production group, parity, days after parturition, and daily milk yield on diurnal variations of metabolites.
Results
Concentrations of glucose, BHBA, and urea remained relatively constant in the herd that was fed by use of automatic distribution of concentrate; however, significant diurnal patterns were detected in the herd fed only twice daily. Only slight differences in glucose and urea concentrations were detected between high- and low-producing cows, but concentration of BHBA was significantly influenced by number of days in lactation. In contrast, diurnal variations in NEFA and cholesterol concentrations were similar between the 2 herds but differed with regard to production group. Concentrations of TP did not have relevant diurnal patterns and did not differ between production groups.
Conclusions and Clinical Relevance
Diurnal variations and feeding frequency affect glucose, BHBA, and urea concentrations in cows. In contrast, concentrations of NEFA, cholesterol, and TP appear to be less sensitive to time of sample collection. Feeding frequency, composition of feed, or both, have a major impact on blood metabolites concentrations. (Am J Vet Res 1999;60:1493–1499)
Abstract
Objective
To evaluate diurnal variation in concentrations of selected markers of bone metabolism in dogs.
Animals
Ten 3-to 4-year-old ovariectomized Beagles.
Procedure
Blood and urine samples were obtained in the morning before dogs were fed (8 am) and then at 2-hour intervals for 24 hours. This procedure was repeated 2 weeks later. Concentrations of osteocalcin OC and carboxy terminal telopeptide of type-I collagen (ICTP) were measured in serum, using a radioimmunoassay; concentrations of hydroxyproline (HYP), pyridinoline (PYD), and deoxypyridinoline (DPD) were analyzed in urine. Hydroxyproline concentration was measured by means of a colorimetric test, whereas PYD and DPD concentrations were quantified by use of high-performance liquid chromatography.
Results
In both parts of the study, hyp concentrations increased significantly, compared with values before feeding, until 8 hours after feeding; hyp concentrations then returned to prefeeding values. Concentrations of DPD and PYD decreased from before feeding until 2 pm and then increased until 8 pm. The ICTP concentrations slowly decreased until 4 pm but returned to prefeeding values thereafter. In both parts of the study, concentrations of oc decreased during the day and then increased to reach values similar to those obtained before feeding.
Conclusions
Changes in the concentrations of bone markers were detected throughout the day in the dogs of this study. Increase in hyp concentration most likely was related to feeding. As documented for bone resorption and formation in other species, circadian rhythms were evident for concentrations of DPD, PYD, and oc. Investigators should consider the time of sample collection when measuring these markers. (Am J Vet Res 1999;60:949-953)
Abstract
Objective—To compare bone mineral measurements obtained by use of dual-energy x-ray absorptiometry (DEXA), peripheral quantitative computed tomography (pQCT), and chemical-physical analyses and determine effects of age and femur size on values obtained for the various techniques.
Sample Population—Femurs obtained from 15 juvenile and 15 adult large-breed dogs.
Procedure—In each femur, 7 regions of interest were examined by use of DEXA to measure the bone mineral content (BMC) and bone mineral density (BMD), and 5 were examined by use of pQCT to measure BMD. Among these, 1 region was examined by both noninvasive methods and an invasive method. Volume of the femur was determined by water displacement. Volumetric bone density (VBD) was calculated. Calcium (Ca), phosphorus (P), total Ca, and total P contents were determined.
Results—DEXA- and pQCT-derived results revealed that all values increased with age in juvenile dogs. In adults, VBD and pQCT-derived BMD decreased significantly and DEXA-derived BMD increased with increasing femur length. The pQCT-derived BMD correlated well with VBD and Ca content, whereas DEXA-derived BMC was strongly correlated with Ca content. In juveniles, values correlated regardless of the technique used, whereas in adult dogs, DEXA-derived BMD did not correlate with pQCT-derived BMD, Ca concentration, or VBD unless data were adjusted on the basis of femur length.
Conclusions and Clinical Relevance—DEXA-derived BMD adjusted for femur length yields approximately the same percentage variability in VBD as for pQCT-derived BMD. However, pQCT-derived BMD is still more sensitive for determining variability in Ca concentration, compared with DEXA-derived BMD adjusted for femur length. (Am J Vet Res 2004;65:891–900)
Abstract
OBJECTIVE To investigate effects of metoclopramide orally administered to healthy bitches on serum prolactin and milk lactose concentrations, gross energy, and dry matter content and on puppy weight gain during early lactation.
ANIMALS 20 client-owned bitches and their 121 puppies.
PROCEDURES 10 bitches received metoclopramide (0.2 mg/kg, PO, q 6 h for 6 days; treatment group) starting 10 to 24 hours after birth of the last puppy of the litter (day 0), and 10 bitches served as the control group. Blood and milk samples from all bitches were collected on days 0, 1, 2, 4, and 6. Milk samples for days 1 and 2 and days 4 and 6 were pooled because of small volume. Puppies were weighed twice daily.
RESULTS Serum prolactin concentration increased significantly over time in both groups, and no treatment effect was detected. When day-to-day changes were analyzed, the prolactin concentration increased from day 0 to day 1 in the treatment group but not in the control group. Milk lactose concentration increased significantly and was higher in the treatment group than in the control group. Milk dry matter content was unchanged, whereas the time course for milk gross energy content differed significantly between treatment and control bitches. Puppy weight gain was not affected by metoclopramide treatment.
CONCLUSIONS AND CLINICAL RELEVANCE Oral administration of metoclopramide to healthy bitches after parturition induced a transient increase in serum prolactin concentration and stimulated milk lactose production. It is likely bitches with insufficient or delayed milk production could benefit from metoclopramide treatment.
