Howard D. Tyler

Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States

The objective of this study was to characterize the quality of maternal colostrum (MC) fed to newborn dairy calves in the United States and identify the proportion of MC that meets industry standards for IgG concentration and total plate count (TPC). Samples of MC (n=827) were collected from 67 farms in 12 states between June and October 2010. Samples were collected from Holsteins (n=494), Jerseys (n=87), crossbred (n=7), and unidentified dairy cattle (n=239) from first (n=49), second (n=174), third or greater (n=128), and unknown (n=476) lactations. Samples were identified as fresh (n=196), refrigerated (n=152), or frozen (n=479) before collection, as well as whether the sample was from an individual cow (n=734) or pooled (n=93). Concentration of IgG in MC ranged from <1 to 200mg/mL, with a mean IgG concentration of 68.8 mg/mL (SD=32.8). Almost 30% of MC contained <50 mg of IgG/mL. The IgG concentration increased with parity (42.4, 68.6, and 95.9 mg/mL in first, second, and third and later lactations, respectively). No differences in IgG concentration were observed among breeds or storage method; however, IgG was highest in samples collected in the Midwest and lowest in samples collected in the Southwest (79.7 vs. 64.3 mg/mL). Total plate count of samples ranged from 3.0 to 6.8 log(10) cfu/mL, with a mean of 4.9 log(10) cfu/mL (SD=0.9) and was greater in samples collected in the Southeast compared with other regions of the country. Pooled samples had greater TPC than individual samples and refrigerated samples had greater TPC than frozen and fresh samples. Almost 43% of samples collected had TPC >100,000 cfu/mL, 16.9% of the samples had >1 million cfu/mL. Only 39.4% of the samples collected met industry recommendations for both IgG concentration and TPC. Almost 60% of MC on dairy farms is inadequate, and a large number of calves are at risk of failure of passive transfer or bacterial infections, or both. Also, the data indicate that regional differences exist in colostrum quality.

The use of bovine serum protein as an oral support therapy following coronavirus challenge in calves

Abstract The objective of this experiment was to investigate the therapeutic efficacy of a supplemental bovine serum protein blend fed to calves challenged with virulent coronavirus. Twelve Holstein bull calves (approximately 3 wk of age) were allocated by initial body weight to Control (n = 5) and treated (n = 7) groups. On d 0, all calves were orally challenged with 1 × 107 plaque forming units of virulent coronavirus isolate. Infection was allowed to progress for 24h before treatment was started. On d 1, treated calves began receiving 160g of dry bovine serum powder (16g IgG) mixed into milk replacer powder (67g) at both an a.m. and p.m. feeding. Control calves received only milk replacer powder (227g) at both feedings. Response to coronavirus challenge and dietary treatment was monitored prior to a.m. and p.m. feeding by the collection of multiple clinical measures. Fecal consistency was decreased by coronavirus challenge but was not affected by dietary treatment. Mean daily rectal temperature and heart rate were not affected by dietary treatment. Average packed cell volume was higher in treated calves than in control (35.0 and 27.0%). Coronavirus challenge resulted in an immediate increase in respiration rate, decreasing by d 7. Control calves tended to have a greater average respiration rate compared with treated (28.7 vs. 26.8 breaths/min). Treated calves had a higher average feed intake than control (0.57 vs. 0.44 kg/d). These data suggest that bovine-serum supplemented milk replacer may decrease the severity of disease in young calves exposed to coronavirus.

Estimate of colostral immunoglobulin G concentration using refractometry without or with caprylic acid fractionation

Our objectives were to evaluate the use of refractometry as a means of estimating immunoglobulin G (IgG) concentration of bovine maternal colostrum (MC) and determine if fractionation of MC using caprylic acid (CA) improved estimates of IgG. Samples (n=85) of MC were collected from a single dairy in California and used to determine the method of CA fraction that produced the best prediction of IgG based on CA fractionation followed by refractometry. Subsequently, samples of MC (n=827) were collected from 67 farms in 12 states to compare refractometry with or without CA fractionation as methods to estimate IgG concentration. Samples were collected from the feeding pool and consisted of fresh (n=196), previously frozen (n=479), or refrigerated (n=152) MC. Samples were further classified by the number freeze-thaw cycles before analysis. Fractionation with CA was conducted by adding 1 mL of MC to a tube containing 75 μL of CA and 1 mL of 0.06 M acetic acid. The tube was shaken and allowed to react for 1 min. Refractive index of the IgG-rich supernatant (nDf) was determined using a digital refractometer. Whole, nonfractionated MC was analyzed for IgG by radial immunodiffusion (RID) and refractive index (nDw). The relationship between nDf and IgG (r=0.53; n=805) was weak, whereas that between nDw and IgG was stronger (r=0.73; n=823). Fresh samples analyzed by refractometry that subsequently went through 1 freeze-thaw cycle before RID analysis resulted in the strongest relationship between IgG and nDf or nDw (r=0.93 and 0.90, respectively). The MC samples collected fresh on the farm but frozen 2 or more times before analysis by refractometry or RID had low correlations between IgG and nDf and nDw (r=0.09 and 0.01). Samples refrigerated or frozen on the farm before analysis had weaker relationships between RID and nDf or nDw (r=0.38 to 0.80), regardless of the number of freeze-thaw cycles. Breed and lactation number did not affect the accuracy of either test. These results indicated that refractometry, without or with CA fractionation, was an accurate and rapid method to determine IgG concentration when samples of MC were not previously stored before refractometry and frozen only once before RID analysis.

Estimate of serum immunoglobulin G concentration using refractometry with or without caprylic acid fractionation

Objectives of this study were to develop a rapid calf-side test to determine serum IgG concentrations using caprylic acid (CA) fractionation, followed by refractometry of the IgG-rich supernatant and compare the accuracy of this method with results obtained using refractometry using raw serum. Serum samples (n=200) were obtained from 1-d-old calves, frozen (-20°C), and shipped to the laboratory. Samples were allowed to thaw for 1h at room temperature. Fractionation with CA was conducted by adding 1mL of serum to a tube containing 45, 60, or 75µL of CA and 0.5, 1.0, or 1.5mL of 0.06 M acetic acid. The tube contents were mixed well, allowed to react for 1 min, and then centrifuged at 3,300 × g for 0, 10, or 20 min at 25°C. The %Brix and refractive index of the fractionated supernatant were determined using a digital refractometer. Nonfractionated serum was analyzed for %Brix (BRn), refractive index (nDn), and IgG concentration by radial immunodiffusion. The mean serum IgG concentration was 19.0 mg/mL [standard deviation (SD)=9.7], with a range of 3.5 to 47.0 mg/mL. The mean serum BRn was 8.6 (SD=0.91), with a range of 6.8 to 11.0. The mean serum nDn was 1.34566 (SD=0.00140), with a range of 1.34300 to 1.34930. Serum nDn was positively correlated with IgG concentration (correlation coefficient=0.86; n=185). Fractionated samples treated with 1mL 0.6 M acetic acid and 60µL of CA and not centrifuged before analysis resulted in a strong relationship between the refractive index of the fractionated supernatant and IgG (correlation coefficient=0.80; n=45). Regression was used to determine cut points indicative of 10, 12, and 14 mg of IgG/mL to determine the sensitivity and specificity of refractometry to identify failure of passive transfer (serum IgG <10 mg/mL at 24 h old). The nDn were 1.34414, 1.34448, and 1.34480 to predict 10, 12, and 14 mg of IgG/mL of serum, respectively. The BRn cut points were 7.6, 7.8, and 8.0, respectively. The nDn cut points of 1.34448 and 1.34480 resulted in similar specificities (82.9%), whereas the 1.34414 cut point had a specificity of 60.0%. The BRn cut point of 7.6 and 7.8%Brix resulted in a similar percentage of correctly classified samples (89.7 and 90.8%, respectively); however, the 7.8% Brix cut point resulted in fewer false positives. These results suggest that Brix refractometry of nonfractionated calf serum provides a strong estimate of IgG concentration and 7.8% Brix may be used as the cut point to identify failure of passive transfer in 1-d-old calves.

Validating a refractometer to evaluate immunoglobulin G concentration in Jersey colostrum and the effect of multiple freeze–thaw cycles on evaluating colostrum quality

The objectives of this study were to (1) validate a method using refractometry to rapidly and accurately determine immunoglobulin (IgG) concentration in Jersey colostrum, (2) determine whether there should be different refractive index (nD) and %Brix cut points for Jersey colostrum, and (3) evaluate the effect of multiple freeze-thaw (FT) cycles on radial immunodiffusion (RID) and a digital refractometer to determine IgG concentration in Jersey colostrum. Samples (n=58; 3L) of colostrum were collected from a dairy in northwestern Iowa. Samples were analyzed within 2h of collection for IgG concentration by RID, %Brix, and nD by refractometer and an estimate of IgG by colostrometer. Samples were frozen, placed on dry ice, and transported to the laboratory at Iowa State University (Ames). Samples arrived frozen and were placed in a -20°C manual-defrost freezer until further analysis. On d 7 (1FT), d 14 (2FT), and 1yr (3FT) all samples were thawed, analyzed for IgG by RID, %Brix, nD by refractometer, and IgG estimate by colostrometer, and frozen until reanalysis at the next time point. Fresh colostrum had a mean (±SD) IgG concentration of 72.91 (±33.53) mg/mL, 21.24% (±4.43) Brix, and nD 1.3669 (±0.0074). Multiple FT cycles did affect IgG as determined by RID and colostrometer reading. The IgG concentrations were greater in fresh and 1FT samples as compared with 2FT and 3FT samples (72.91, 75.38, 67.20, and 67.31mg of IgG/mL, respectively). The colostrometer reading was lower in 1FT samples compared with fresh and 2FT samples. Multiple FT cycles had no effect on nD or %Brix reading. In fresh samples, IgG concentration was moderately correlated with nD (r=0.79), %Brix (r=0.79), and colostrometer reading (r=0.79). Diagnostic test characteristics using the recommended cut point of 1.35966 nD resulted in similar sensitivities for 1FT and 2 FT samples (94.87 and 94.74%, respectively). Cut points of 18 and 19% Brix resulted in the greatest sensitivities (92.31 and 84.62%) and specificity (94.74 and 94.74%, respectively). The 18% Brix cut point resulted in 94.83% of the samples being correctly classified based on IgG concentration. These data support the use of digital refractometer to accurately and rapidly determine IgG concentration in fresh Jersey colostrum. Additionally, these data suggest that IgG concentration determined by RID is affected by multiple FT cycles, whereas estimates obtained by refractometer are not affected by multiple FT cycles.

Evaluation of mechanical and thermal nociception as objective tools to measure painful and nonpainful lameness phases in multiparous sows

The objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal nociception threshold (TNT) tests when sows were in painful and nonpainful transient lameness phases. A total of 24 mixed parity crossbred sows (220.15 ± 21.23 kg) were utilized for the MNT test, and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the TNT test. On induction day (D0), all sows were anesthetized and injected with Amphotericin B (10mg/mL) in the distal interphalangeal joint space in both claws of one randomly selected hind limb to induce transient lameness. Three days were compared: (1) D-1 (sound phase, defined as 1 d before induction), (2) D+1 (most lame phase, defined as 1 d after induction), and (3) D+6 (resolution phase, defined as 6 d after induction). After completion of the first round, sows were given a 7-d rest period and then the procedures were repeated with lameness induced in the contralateral hind limb. During the MNT test, pressure was applied perpendicularly to 3 landmarks in a randomized sequence for each sow: 1) middle of cannon on the hind limb (cannon), 2) 1 cm above the coronary band on the medial hind claw (medial claw), and 3) 1 cm above the coronary band on the lateral hind claw (lateral claw). During the TNT test, a radiant heat stimulus was directed 1 cm above the coronary band. The data were analyzed using the MIXED procedure in SAS with sow as the experimental unit. Differences were analyzed between sound and lame limbs on each day. For the MNT test, pressure tolerated by the lame limb decreased for every landmark (P < 0.05) when comparing D-1 and D+1. The sound limb tolerated more pressure on D+1 and D+6 than on baseline D-1 (P < 0.05). Thermal stimulation tolerated by the sound limb did not change over the 3 d (P > 0.05). However, the sows tolerated less heat stimulation on their lame limb on D+1 compared to D-1 levels (P < 0.05). Both MNT and TNT tests indicated greater pain sensitivity thresholds when sows were acutely lame.

Effects of d-α-tocopherol and dietary energy on growth and health of preruminant dairy calves

To observe the effects of supplemental dietary d-α-tocopherol in relation to dietary energy on growth and immune status in dairy calves, 32 newborn Holstein bull calves were assigned to 1 of 4 treatments for 5 wk in a 2 × 2 factorial, randomized complete block, split-plot design. Calves received moderate growth (MG) or low growth (LG) all-milk dietary treatments, formulated to support daily gains of 0.5 or 0.25 kg/d, respectively, per the dietary energy recommendation for milk-fed calves according to the National Research Councils Nutrient Requirements of Dairy Cattle. Calves in both groups were either injected i.m. with Vital E-A+D (injectable solution of vitamins E, A, and D) on d 1 and supplemented with Emcelle Tocopherol (micellized vitamin E) via milk daily (MG-S and LG-S), or were not supplemented (MG-C and LG-C) during the study period. Total weight gain of MG calves was greater than that of LG calves and tended to be greater in MG-S calves than in MG-C calves. Calves receiving vitamin supplementation demonstrated greater concentrations of plasma α-tocopherol, retinol, and 25-(OH)-vitamin D than did control calves, whereas MG calves demonstrated a lower concentration of plasma α-tocopherol than did LG calves. The apparent increased utilization of α-tocopherol by MG calves was accompanied by a rise in serum haptoglobin, a positive acute-phase protein and indicator of inflammation, especially in MG-C calves. Serum amyloid A, also a positive acute-phase protein, was not different among groups, but was elevated from baseline in all groups during wk 1 through 3. Plasma IgG1 concentrations were higher in MG-S and LG-S calves than in their nonsupplemented dietary counterparts, whereas plasma IgG2, IgA, and IgM concentrations were not different among groups. In summary, dietary supplementation of d-α-tocopherol improved plasma α-tocopherol status and tended to increase growth in calves fed for 0.5 kg of average daily gain. Vitamin supplementation ameliorated the rise of serum haptoglobin associated with acute inflammation in MG calves, and may have improved passive transfer of maternal antibody. These results indicate a role for α-tocopherol in prevention of proinflammatory state associated with greater dietary energy and onset of infectious disease.

Short communication: The effect of 4 antiseptic compounds on umbilical cord healing and infection rates in the first 24 hours in dairy calves from a commercial herd

The objective of this study was to compare the effect of 4 antiseptic compounds on the healing rate and incidence of infection of umbilical cords in newborn calves (n=60). Late gestation Jersey cows were monitored at a commercial farm (Sioux Jersey, Salix, IA) and newborn purebred (n=30) and crossbred (n=30) calves were obtained within 30min after birth. Calves were alternately assigned by birth order to 4 treatment groups: 7% tincture of iodine, 0.1% chlorine created using a novel chlorine disinfectant technology, chlorohexidine gluconate 4.0% wt/vol, and 10% trisodium citrate. Prior to dipping (within 30min of birth), diameter of the umbilical cords (as an indicator of cord drying and healing) were determined using digital calipers. In addition, as an indicator of umbilical infections, surface temperature of the umbilical stump (along with a reference point at the midpoint of the sternum) was determined using a dual-laser infrared thermometer. These measurements were all repeated at 24±1 h of age. All data were analyzed using mixed model methods. All models included fixed effects of breed (Jersey or Jersey cross), sex (bull or heifer), and treatment. Fixed effect interactions were not included in the statistical model due to the relatively small sample size. No treatment differences were noted for healing rate of umbilical cords. Initially, mean umbilical cord diameter was 22.84±3.89mm and cords healed to a mean diameter of 7.64±4.12mm at 24 h of age. No umbilical infections were noted for calves on any treatment during the course of this study. Mean surface temperature of the umbilical stump was 33.1±2.2°C at birth (1.5±1.6°C higher than the sternal reference temperature), and at 24±1 h of age the mean temperature of the umbilical stump was 33.0±4.3°C (0.5±1.8°C lower than the sternal reference temperature). These data suggest that these antiseptic compounds are equally effective for preventing infections and permitting healing of the umbilical cord when used within 30min of birth.

Altered Concentrations of Aldosterone in Neonatal Calves During Chronic Hypoxia and the Subsequent Recovery Period

Significant changes occur in both blood composition and plasma volume of the calf within the first few hour after parturition (McEwan et al., 1968). These changes require sensitive and reliable regulatory mechanisms to maintain electrolyte balance and prevent fluid dyshomeostasis. Although the time required for maturation of the renal system in calves is much shorter than in most experimental animals (Dalton, 1968), significant electrolyte imbalances are a common clinical finding in neonatal calves.

Development of an In Vivo Perfusion System for Bovine Fetal Small Intestine

Previous work at this institution has focused on the role of oxygen availability on the development of bovine small intestine during the perinatal period. In particular, the change in arterial oxygen tension associated with the conversion from placental to pulmonary respiration at birth was hypothesized to initiate an alteration in intestinal macromolecular permeability during the first 24 hours of life that is characteristic of the bovine neonate. The first model used to test this hypothesis was the hypoxic postnatal calf (Tyler and Ramsey, 1989). By providing the newborn calf with a 90:10 mixture of N2:O2, arterial PO2 was maintained at a level similar to that of the fetal calf. The results of this study were inconclusive, however, which may have been due to other changes occurring at birth that influence intestinal development.