Using heart rate to predict energy expenditure in large domestic dogs

The aim of this study was to establish heart rate as a measure of energy expenditure in large active kennel dogs (28 ± 3 kg bw). Therefore, the heart rate (HR)–oxygen consumption () relationship was analysed in Foxhound‐Boxer‐Ingelheim‐Labrador cross‐breds (FBI dogs) at rest and graded levels of exercise on a treadmill up to 60–65% of maximal aerobic capacity. To test for effects of training, HR and were measured in female dogs, before and after a training period, and after an adjacent training pause to test for reversibility of potential effects. Least squares regression was applied to describe the relationship between HR and . The applied training had no statistically significant effect on the HR– regression. A general regression line from all data collected was prepared to establish a general predictive equation for energy expenditure from HR in FBI dogs. The regression equation established in this study enables fast estimation of energy requirement for running activity. The equation is valid for large dogs weighing around 30 kg that run at ground level up to 15 km/h with a heart rate maximum of 190 bpm irrespective of the training level.     

Corneal innervation in mesocephalic and brachycephalic dogs and cats: assessment using in vivo confocal microscopy

Objective To determine the density of the canine and feline corneal neural network in healthy dogs and cats using in vivo confocal microscopy (IVCM). Animals examined A total of 16 adult dogs (9 Mesocephalic breeds, 7 Brachycephalic breeds) and 15 cats (9 Domestic Short-haired cats (DSH), 6 Persian cats) underwent IVCM. Procedure Animals were examined with a confocal corneal microscope (HRTII/RCM; Heidelberg Retina Tomograph II/Rostock Cornea Module^®, Heidelberg Engineering, Dossenheim, Germany). The investigations focused on the distribution of the corneal nerves and quantification of central subepithelial and subbasal nerve plexus. Results The corneal stromal nerve trunks, subepithelial and subbasal nerve plexus were observed. The nerve fiber density (NFD) quantified in nerve fiber length in mesocephalic dogs were 12.39 ± 5.25 mm/mm² in the subepithelial nerve plexus and 14.87 ± 3.08 mm/mm² in the subbasal nerve plexus. The NFD of the subepithelial nerve plexus in DSH cats was 15.49 ± 2.7 and 18.4 ± 3.84 mm/mm² in the subbasal nerve plexus. The subbasal NFD of DSH cats was significantly higher than in mesocephalic dogs (P = 0.037). The subepithelial NFD in brachycephalic dogs, and Persian cats were 10.34 ± 4.71 and 9.50 ± 2.3 mm/mm², respectively. The subbasal NFD measured 11.80 ± 3.73 mm/mm² in brachycephalic dogs, and 12.28 ± 4.3 mm/mm² NFD in Persian cats, respectively. The subepithelial and subbasal NFD in Persian cats were significantly lower than in DSH cats (P = 0.028, respectively, P = 0.031), in contrast to brachycephalic vs. mesocephalic dogs. Conclusion The noninvasive IVCM accurately detects corneal innervation and provides a reliable quantification of central corneal nerves.     

Addition of fat to the diets of lactating sows: I. Effects on milk production and composition and carcass composition of the litter at weaning.

In Exp. 1 two groups of 18 sows were used to evaluate the effects of supplemental dietary fat on sow and litter performance and milk production and composition. Sows were provided ad libitum access to either a corn-soybean meal (control) diet or a similar diet containing 10% tallow. Feed intake, ME intake, and milk yield did not differ (P > .10) between treatments. The percentage of solids in milk was greater (P < .05) for sows fed the tallow diet, due to an increase (P < .05) in the fat and ash content. Compared with percentages of fatty acids in milk of sows fed the control diet, the percentages of C10:0, C14:0, C16:0, C16:1, and C18:3 fatty acids were lower (P < .05) and the percentages of C18:0 and C18:1 fatty acids were higher in milk of sows fed tallow diets (P < .05). In Exp. 2, 30 sows were fed diets similar to those fed in Exp. 1, and the effects of a tallow diet on pig carcass composition at weaning were determined. Litter size was standardized to 10 pigs. There were no differences (P > .10) in ADFI of sows. Daily ME intake was greater for sows fed tallow than for control sows during wk 2 (P < .05), wk 3 (P < .10), and the entire lactation (P < .05) period. Litter weaning weight was greater (P < .05) for pigs from sows fed tallow diets than for pigs from control sows. Pigs from tallow-fed sows had greater carcass fat weight and fat percentages (P < .05) and lower water and protein percentages (P < .05). These data indicate that the increased fat content of milk from sows fed tallow diets resulted in an increased weight gain for litters nursing these sows. The composition of the increased weight gain is almost exclusively fat.