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.

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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.

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.

In this study the relationship between perceived change implementation in an organization is related to employee self‐rated behaviour. The change implementation processes measured were communication, support and participation. The relationship between these processes and employee behaviour was examined by testing a theoretical model, in which two mediating concepts are used: the psychological contract and employee job attitudes. The research was carried out in two main divisions of a large telecommunications firm on a sample of 220 employees. The theoretical model (perceived change implementation influencing the psychological contract, influencing employee attitudes, influencing employee behaviour) had a better fit with the data, compared to alternative models.