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Five primiparous Holstein cows were cannulated in the rumen, duodenum, and ileum and were fed diets containing 50% alfalfa silage and 36.6% coarse-, medium-, or fine-ground corn (CGC, MGC, and FGC, respectively, with mean particle sizes of 4.8, 2.6, or 1.2 mm), steam-rolled corn (SRC; density of 0.53 kg/L), or a 50:50 mix of CGC and SRC (SC) to evaluate how corn processing affects site of digestibility of nonstructural carbohydrates (NSC) and neutral detergent fiber (NDF). Decreasing the particle size of corn quadratically affected true ruminal digestibility of NSC (49.8, 46.5, and 87.0%, respectively). Because of compensatory digestion postruminally, a smaller increase (from 91.3 to 98.0%) in total tract digestibility of NSC was noted as particle size decreased. A small but significant linear shift in NDF digestion from the rumen to the large intestine was detected as corn particle size decreased. The addition of SRC to CGC linearly increased true NSC digestibility in the rumen about 20 percentage units but had much smaller effects on total tract digestibility. Despite the large impact of corn processing on NSC digestibility in the rumen, flow of bacterial N to the rumen was not affected by treatment. Reducing the particle size of corn decreased the apparent escape of corn protein, but steam-rolling had no effect. Corn should be finely ground to maximize total tract OM digestibility or steam-processed to densities less than 0.53 kg/L for maximal starch digestibility. However, fine-grinding or steam-processing of corn may have only a modest impact on total tract OM digestibility.

Four primiparous Holstein cows in late lactation were used in a 4 x 5 Youden square design. Each cow was fitted with ruminal, duodenal, and ileal cannulas. Treatments were a control diet with a high concentration of forage, a control diet with a low concentration of forage, and three diets in which dried brewers grains replaced a portion of the forage, concentrate, or both. Cows were fed and milked twice daily in 14-d periods. Chromic oxide and Yb (soaked in acid) were used as markers for digesta flow and rate of passage, respectively. No significant differences in ruminal pH or rates of passage caused by treatment were detected. Although brewers grains had slower digestion rates of neutral detergent fiber (NDF) in situ and faster passage rates than did alfalfa, brewers grains had minor effects on site of NDF digestion. Intake of dry matter was depressed by the higher NDF concentrations in diets in which brewers grains replaced concentrate, but a long-term feeding study is needed to verify this conclusion. Although brewers grains did not appear to be very effective at stimulating milk fat percentage, dry matter intake was maintained when brewers grains replaced forage, and it appears that brewers grains can successfully replace a portion of the forage NDF in the diets of lactating cows.

Six cannulated cows were assigned to six treatments in a 6 x 6 Latin square design to evaluate the effects of fat saturation and amount and source of effective fiber on fatty acid metabolism. Cows were fed a control diet with no added fat or diets with 5% added fat from saturated tallow, tallow, or animal-vegetable fat; the diets with animal-vegetable fat had three percentages of effective fiber: 40% forage, 40% forage plus 20% soyhulls, or 60% forage. Cows fed diets supplemented with fat tended to have more disappearance of total fatty acids in the rumen than did those fed the control diet. Disappearance of fatty acids from the rumen, especially C16 and C18, was higher for cows fed the low fiber diet. The apparent digestibility of fatty acids in the small intestine was higher for cows fed the control diet than for those fed supplemental fat. Apparent digestibility also was reduced as fat saturation increased, primarily because of saturated tallow. Digestibility of C18:1 in saturated tallow was reduced, apparently in association with other saturated fatty acids. Fiber source had no effects on apparent intestinal digestibility of fatty acids. Concentrations of C18:0 and C18:1 in milk fat increased as the degree of fat saturation decreased, reflecting higher unsaturated C18 intake and ruminal biohydrogenation of polyunsaturated C18 fatty acids.

Although lameness caused by fractures and luxations of the pelvis and proximal femur are rare, they are serious and often end an animal's productive life unless properly diagnosed and promptly treated. Diagnosis of these injuries is difficult without special radiographic equipment; however, careful physical examination will often lead to a tentative diagnosis. Coxofemoral luxations and slipped capital epiphysis are two of these life-threatening injuries. This article discusses their diagnosis and possible options for treatment, which can lead to a useful, productive life. The diagnosis of other pelvic injuries is discussed, although these injuries are often not as amenable to treatment.

Six primiparous cannulated cows were assigned to six treatments in a 6 x 6 Latin square design to evaluate the effects of degree of fat saturation and amount and source of effective fiber on site of nutrient digestion and milk production. Cows were fed for ad libitum intake a control diet with no added fat or diets with 5% added fat from saturated tallow, tallow, or animal-vegetable fat; the diets with animal-vegetable fat had 40% forage, 40% forage plus 20% soyhulls, or 60% forage. Ruminal acetate:propionate was higher when soyhulls replaced forage NDF because of the higher digestibility of soyhulls in the rumen and total tract. Ruminal digestion of NDF was decreased as unsaturation of fat increased. True and apparent efficiencies of bacterial protein synthesis were increased as fat unsaturation increased, probably because of reduced recycling of microbial N in the rumen. The digestibility of fatty acids in the small intestine was higher in cows fed no fat than in those fed fat and was reduced as fat unsaturation decreased, primarily because of the saturated tallow. Dry matter intake was decreased 14% by increased fat unsaturation. All fat supplements depressed milk protein percentage. Production of 4% FCM tended to decrease linearly as unsaturation of fat increased. In diets with 5% added fat, a degree of saturation between saturated tallow and tallow (iodine values of 18 and 62) appears to be optimum for fatty acid digestibility and DMI.

Three diets were fed to six cannulated heifers in a replicated 3 x 3 Latin square design. Diets were a high forage control, a high forage diet with dextrose (5.6% of DM), and a medium concentrate (39.7% of DM) diet. Diets contained 13.3% CP and 1% NaHCO3 and were fed as a TMR twice daily. Mean ruminal pH (6.47), glucose concentration (.55 mM), and reducing sugar concentration (.64 mM) in heifers were similar across diets. Rate of orchardgrass NDF digestion in situ was faster for heifers fed the dextrose than for those fed the medium concentrate diet, but both were similar to that for heifers fed the control diet. Heifers fed the medium concentrate and dextrose diets had faster ruminal particulate fractional passage rates than those fed the control diet. True ruminal and apparent total tract digestion of OM and NDF were similar among diets, but ruminal NDF digestion tended to be higher with the control than with the medium concentrate diet. Total NAN and bacterial N flow to the duodenum and efficiency of bacterial protein synthesis in the rumen were greater with the medium concentrate diet than with the control and dextrose diets. The results were consistent with others that demonstrated that factors related to nonstructural carbohydrates in the diet other than just low ruminal pH affect ruminal fiber digestion; however, these results were not as strong as those of our previous in vitro work.

A one-week-old Brown Swiss calf had fractures of the metaphyseal regions of the left femur and right tibia, and a generalised, severe derangement of osteogenesis. Alternating zones of sclerosis and radiolucency in the metaphysis of all the long bones was visible radiographically. A histopathological examination revealed a segmental disruption of trabecular modelling, with subsequent fracture. Immunohistochemistry using a monoclonal antibody for bovine viral diarrhoea (BVD) virus revealed abundant viral antigen in the pituitary gland, hypothalamus and thyroid gland. Intestinal tissue was positive on fluorescent antibody testing for the virus. The lesions indicate that transplacental infection with BVD virus can result in severe skeletal abnormalities and fractures.

Medical records of 12 calves less than or equal to 1 month old, with fracture of the femoral diaphysis, were reviewed. Ten calves were within 1 week of birth at the time of diagnosis. Open reduction was accomplished by use of a lateral approach. Retrograde intramedullary pinning was accomplished in all calves, using 2 (n = 4 calves) or 3 (n = 8 calves) pins. Cerclage wire was used to supplement fixation in 7 calves. A closed continuous suction drain was placed along the lateral aspect of the femur in every calf. Postsurgical complications included seroma formation over the middle gluteal musculature (n = 5 calves), pin migration (n = 6 calves), and osteomyelitis (n = 1 calf). Pin migration was observed in 4 calves that had been treated with nonthreaded trochar point pins. Fractures in 10 of 12 calves (83%) were considered to have healed satisfactorily. One calf was euthanatized because of septic osteomyelitis of the femur. One calf was euthanatized because of persistent lameness and pin migration. Pins were removed in 8 of 12 calves (67%) between the 13th and 90th postoperative days. Results of this study indicate that application of intramedullary pins may be a useful solution for management of femoral diaphyseal fracture in young calves.

The purpose of this study was to evaluate the effect of withdrawal of lactose from the diet for 72 hours on lactase activity in the jejunal mucosa of conventionally raised calves. The descending portion of the duodenum of six Holstein calves less than 24 hours old was cannulated. The calves were fed milk except on days 5, 6 and 7 when they were given the same volume of an electrolyte solution. Sequential biopsy specimens of the proximal jejunal mucosa were obtained for three weeks and the lactase activity determined. Lactase activity was highest on day 1 and a trend toward decreased lactase activity from birth until three weeks was observed. Mean lactase activity was significantly (p less than 0.05) higher for days 1, and 3 compared to days 9, 13 and 17. The withdrawal of milk and replacement by an electrolyte solution during three days had no significant effect on jejunal mucosal lactase activity in neonatal calves.

Four Holstein heifers cannulated in the rumen and proximal duodenum were used to analyze effects of Aspergillus oryzae fermentation extract and yeast culture (Amaferm Micro-Mix. Biozyme Enterprises, Inc., St. Joseph, MO) and 5% animal-vegetable fat on ruminal and total tract digestibilities of nutrients. Heifers were assigned treatments in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Few interactions between main effects were noted. Feeding fat decreased ruminal molar ratio of acetate:propionate. Rate of disappearance of potentially digestible NDF from orchardgrass hay was higher when heifers were fed fat. Thus, the lack of differences in digestibilities of NDF, ADF, or in the major hemicellulosic sugars is interpreted to suggest that 5% animal-vegetable fat had few toxic effects on ruminal microbes under the conditions of this study. Amaferm Micro-Mix tended to increase acetate:propionate in the rumen, but had little effect on site or extent of digestion of any of the fiber components measured. Efficiency of bacterial protein synthesis was not affected by treatment. Ruminal and total tract digestibilities of total hemicellulosic sugars were highly correlated (r = .82 and .72) with respective digestibilities of hemicellulose measured as NDF minus ADF.

The descending portion of the duodenum of 6 Holstein calves less than 24 hours old was cannulated. Sequential biopsy specimens of the proximal jejunal mucosa were obtained every other day for 3 weeks. Lactase activity in the mucosal specimens was determined and was highest at day 1, but decreased with age. Mean lactase activity was significantly (P less than 0.05) higher for days 1, 3, 5, and 7, compared with days 19 and 21.

This project was designed to develop a standardized cannulation technique which would allow repeated jejunal mucosal biopsy. Three intestinal cannulas of various designs were evaluated in a total of 25 neonatal calves. Cannula A, a T-design made of acrylic plastic, was implanted into the jejunum (2) or duodenum (7). Cannula A did not allow proper directional passage of the biopsy instrument. Peritonitis was diagnosed at necropsy in 4 calves. Cannula B, a modification of A with an angled port to facilitate the directional passage of the biopsy instrument, also proved unsatisfactory. This cannula required a larger enterotomy for placement and resulted in the death of 1 calf. Cannula C was made of tygon tubing with a proxplast mesh flange which was sutured to the serosal surface of the intestine. No intestinal leakage was observed in 14 calves fitted with this cannula. This cannula was the least expensive and allowed the biopsy instrument to be easily directed. Surgical implantation of this cannula (C) in the descending duodenum proved to be an excellent method to obtain successive mucosal biopsies of the jejunum in the neonatal calf.

Tarsal fractures were diagnosed in a heifer and a bull. In both cases, radiography confirmed intra-articular fractures, with subluxation of the fracture fragment. Sudden, nonreducible hock flexion was a clinical sign in both cases. This sign may be highly suggestive of intra-articular fracture when diagnosis must be made without radiography.