Evaluation of methods for dehydration of bovine colostrum for total replacement of normal colostrum in calves

Different methods for the dry preservation of colostrum to be used as a total replacement for bovine colostrum were evaluated. Pooled colostrum from the first and second postpartum milkings from multiparous dairy cows containing immunoglobulin in excess of 40 g/L was freeze-dried, microwave vacuum evaporated, and spray-dried. Spray-drying produced a dried colostrum in which immunoglobulin quantity and function were preserved and was the most cost-effective. Other dehydration methods, although effectively conserving immunoglobulins, were too slow and costly to be used to produce a bovine colostrum replacer. Newborn, colostrum-deprived, dairy calves fed spray-dried colostrum containing 126 grams of immunoglobulin reconstituted in three liters of water as their sole source of immunoglobulin achieved normal mean serum immunoglobulin concentrations. Spray-dried colostrum with high concentrations of immunoglobulin may be produced economically and used as an effective and convenient colostrum replacer in newborn calves.     

Evaluation of the transfer of immunoglobulin from colostrum anaerobic fermentation (colostrum silage) to newborn calves

Colostrum silage is an anaerobic fermentation methodology of excess farm colostrum used to conserve and provide as milk replacement for calves. The present study aimed to evaluate the levels of immunoglobulins present in bovine colostrum silage and its absorption by newborn calves. The concentration of immunoglobulins was determined in fresh colostrum and colostrum silage stored for 12 months. The absorption of immunoglobulins by calves was assessed immediately after birth and 24 h after colostrum silage intake. The immunoglobulin levels were evaluated by ELISA. The results highlighted that colostrum silage kept similar levels of immunoglobulins as the ones in colostrum in natura, and can be transferred to newborn calves with similar amounts to calves fed with colostrum in natura. It is concluded that colostrum silage keeps viable immunoglobulins, and is able to transfer passive immunity to newborn calves.     

Impact of four fiber-rich supplements on nutrient digestibility,colostrum production,and farrowing performance in sows

This study aimed to investigate the impact of dietary fiber (DF) sources on sow and litter performance, and apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients. A total of 48 sows were stratified for body weight at mating and randomly assigned to one of four DF sources (mixed fiber [MF], palm kernel expellers [PKE], sugar beet pulp [SBP], or soy hulls [SH]) and fed the diet from mating until farrowing. Within DF treatments, sows were supplemented with one of two extra energy sources (glycerol or sugar dissolved in water), whereas a third group (control) received water from day 108 of gestation until farrowing. The number of total born, live-born, and stillborn pigs; birth time and birth weight of the pigs; farrowing duration; and farrowing assistance (FA) were recorded. Live-born pigs were weighed again at 12 and 24 h after birth to record weight gain, which was used to estimate intake and yield of colostrum. Blood samples were collected once daily from day −3 relative to farrowing until day 1 after farrowing in sows and once from selected pigs right after birth. Fecal samples were collected on day 114 of gestation and colostrum at 0, 12, 24, and 36 h after onset of farrowing. Intake of soluble and insoluble nonstarch polysaccharides (NSP) was greater for SBP (P < 0.001) and PKE (P < 0.001) supplemented sows, respectively, when compared with other groups. Farrowing duration and stillbirth rate were not affected by DF sources, but PKE and SH supplemented sows had greater FA than SBP and MF supplemented sows (P < 0.001). Extra energy supplement did not improve the farrowing performance. Concentration (P = 0.02) and output (P = 0.04) of dry matter in colostrum, and ATTD of GE (P < 0.001) and crude protein (CP; P < 0.001) were lower for PKE supplemented sows than in sows from the remaining groups. Intake of insoluble NSP correlated negatively with ATTD of GE (P < 0.001) and CP (P < 0.001). Concentrations of glucose (P < 0.001), lactate (P < 0.001), CO₂ (P < 0.001), and HCO₃ (P < 0.001) in sows blood were increased with time progress relative to farrowing. Newborn pigs from PKE supplemented sows had greater concentration of lactate (P = 0.02) and lower blood pH (P = 0.02) than the remaining treatments. In conclusion, PKE supplement reduced ATTD of GE and CP, and concentration and output of dry matter in colostrum but increased FA. Results of this experiment indicated that the use of PKE as a fiber source for late gestating sows should be avoided.     

Evaluation of a cow-side immunoassay kit for assessing IgG concentration in colostrum

OBJECTIVE: To determine sensitivity and specificity of a cow-side immunoassay kit for assessing IgG concentration in colostrum. DESIGN: Prospective study. ANIMALS: 76 dairy and 11 beef cows of various parities. PROCEDURE: Colostrum from first, second, and third milkings and milk samples were collected, and IgG concentration was determined by means of radial immunodiffusion. The immunoassay was performed according to the manufacturer's instructions, and sensitivity and specificity were calculated by comparing results of the immunoassay (positive vs negative) with results of immunodiffusion (< 50 g/L vs > or = 50 g/L). RESULTS: 135 colostrum or milk samples were collected. Mean +/- SD colostral IgG concentrations, determined by means of radial immunodiffusion for dairy and beef cows were 65.4 +/- 51.4 g/L and 114.8 +/- 42.7 g/L, respectively. Mean IgG concentrations for first-, second-, and third-milking colostrum samples and for milk samples were 92 +/- 49.0 g/L, 74.6 +/- 45.1 g/L, 47.5 +/- 32 g/L, and 6.8 +/- 3.8 g/L, respectively. Sensitivity of the immunoassay (ie, percentage of samples with IgG concentration < 50 g/L with a positive immunoassay result) was 93%, and specificity (ie, percentage of samples with IgG concentration > or = 50 g/L with a negative immunoassay result) was 76%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the immunoassay kit was an acceptable cow-side test to identify colostrum samples with IgG concentrations < 50 g/L. The immunoassay kit should be useful in screening colostrum for adequate IgG concentration before feeding to calves or storage.     

Evaluation of two supplements for the prevention of alfalfa bloat.

Poloxalene and a mineral mixture feed supplement patented for the treatment of emphysema, polyarthritis, and other pectin related diseases were tested in two trials for their ability to prevent bloat in cattle fed fresh alfalfa. Each trial had a crossover design using three Jersey steers with rumen fistulas per group. Each trial period continued until the total number of cases of bloat reached > or = 24. Treatments were given at 0800 each day. The mineral mixture was given at 100 g/d and 190 mg/kg body weight per day in the first and second trials, respectively. Poloxalene, which was tested only in the second trial, was given at 23 mg/kg body weight per day. Each group of steers was then fed 200 kg of freshly harvested alfalfa in the vegetative to early bloom stages of growth at 0830. In the first trial, only 69% as many cases of bloat occurred on the mineral mixture as on the control treatment, but no significant difference was detected in the second trial. The potency of the alfalfa may have been higher in the second trial, when forage dry matter was lower, magnesium and soluble nitrogen were higher, and bloat occasionally occurred twice a day. Bloat did not occur when the steers were treated with poloxalene. In these trials, poloxalene was completely effective in preventing bloat, but the mineral mixture was only partially so.     

Evaluation of immunoglobulin G concentration in colostrum of mares by ELISA, refractometry and colostrometry

In 360 samples of colostrum and 36 samples of blood of warmblood mares, the concentration of immunoglobulin G (IgG) was evaluated in the post partal period with an ELISA and the results were compared to values obtained with 2 field methods--refractometry and colostrometry. A significant correlation (p < 0.0001) was determined between ELISA and colostrometry (r = +0.88) and between ELISA and refractometry (r = +0.93). So both field-methods seem suitable for evaluation of the colostral IgG-concentration in mares. Further the kinetic of the IgG concentration in colostrum, the volume of colostrum and the total amount of IgG was measured in the 12 hours post partum (p.p.) in each half udder of 36 mares of different parity. Immediately p.p. primiparous mares have a greater mean concentration of IgG (68 mg/ml) than multiparous mares (51 mg/ml). However, multiparous mares have a mean colostral volume of 1020 ml whereas, in primiparous mares, a mean volume of 527 ml was determined within the first three hours p.p. As a result of this the total amount of IgG was lower in primiparous (31.5 g) than in multiparous mares (48.5 g). A significant decrease of IgG concentration was measured in multiparous mares in the 1.5 hours following partum versus 3 hours in primiparous mares. The mean IgG concentration in the blood serum of the 36 mares immediately p.p. was 13.4 +/- 3.6 mg/ml. No significant correlation was observed between values of IgG concentration in the blood and in the colostrum of the mares.     

Evaluation of killed and modified live porcine rotavirus vaccines in cesarean derived colostrum deprived pigs

Twenty-eight cesarean derived, colostrum deprived (CDCD) piglets were used to evaluate the efficacy of killed and modified live rotavirus (MLV) vaccines against challenge with virulent A-1 and A-2 rotaviruses. Two killed rotavirus vaccines were evaluated: an experimental vaccine and a commercially available vaccine. Efficacy parameters included: average daily weight gains, rotavirus shedding in feces, morbidity incidence and duration, and rotavirus serum antibody conversion post-vaccination and post-challenge. Piglets vaccinated orally/intramuscularly with the modified live vaccine were completely protected from A-1 and A-2 virulent rotavirus challenge. Nonvaccinated control piglets and piglets receiving killed rotavirus vaccines developed diarrhea, shed virus and exhibited reduced weight gains post-challenge. Only the MLV rotavirus vaccine was able to prevent virus shedding in feces after virulent challenge. Both controls and pigs which received killed vaccines intraperitoneally, orally or intramuscularly shed virus in the feces for 7 days post-challenge and virus peak titers approached 10(7) fluorescent antibody infectious dose (FAID)50/g feces. These studies clearly reflected the inability of killed rotavirus vaccines to induce active local immunity to rotaviral diarrhea in piglets.     

Evaluation of colostrum and whey-derived gamma globulins for prevention of cryptosporidiosis in artificially infected neonatal calves

Thirty colostrum-deprived Friesian male calves were used to study the effect of colostrum and whey-derived gammaglobulins on the clinical events and oocyst-excretion pattern following artificial infection with a fresh, field-sourced strain of Cryptosporidium parvum. The calves were raised naive and free from contact with C. parvum from birth until infection at either 10 or 17 days of age. The two age groups comprised three sub-groups that were each given a single treatment of colostrum, whey-derived gammaglobulins or whole milk (controls) at 5 hours after birth. Blood samples taken both before and 48 hours after this dosing showed the mean serum gamma globulin concentrations changed from almost zero in all calves to 462,279 and 29 mg/dl for the colostrum, whey-derived gammaglobulin and whole milk sub-groups respectively. The results showed that a majority of calves shed Cryptosporidium oocysts within 7 days of oral infection but that no diarrhoea or other clinical signs were associated with this. However, when the level of C. parvum faecal shedding was graded, the results showed a trend towards a higher level of oocyst shedding and over a longer period of time in the control calves deprived of any passive immunity than in the two groups given either colostrum or whey-derived gammaglobulins.     

Serum immunoglobulin G concentrations in calves fed fresh colostrum or a colostrum supplement

This study compared serum immunoglobulin G (IgG) concentrations in calves fed colostrum with those of calves fed a colostrum supplement containing spray-dried serum. Twenty-four Holstein calves were randomly assigned to I of 2 treatment groups (fresh colostrum or colostrum supplement). Each calf was fed 4 L of colostrum (n, = 12) or 4 L of colostrum supplement (n2 = 12) via oroesophageal intubation at 3 hours of age. The concentration of the colostrum supplement fed to calves was twice the manufacturer's recommendation. The median and range values for colostral IgG concentration were 6,430 mg/dL and 1,400-17,000 mg/ dL, respectively. Median serum IgG concentrations at 2 days of age differed significantly (P = .001) between calves receiving fresh colostrum (3,350 mg/dL) and the colostrum supplement (643 mg/dL). Eight percent of calves force fed colostrum had serum IgG concentrations < 1,000 mg/dL, whereas 75% of calves force-fed supplement had IgG concentrations below this threshold. The calculated population relative risks for mortality associated with passive transfer for calves force-fed colostrum and calves force-fed colostrum supplement were 1.09 and 1.90, respectively. Force-fed fresh colostrum is superior to the colostrum supplement studied, but the colostrum supplement has similar efficacy to routine colostrum administration practices.     

牛初乳的研究进展

初乳是指奶牛分娩后7 d内特别是3 d内所分泌的乳汁,新鲜初乳色泽黄而浓稠、酸度高、具有特殊的乳腥味和苦味.     

Detection of cytokines in bovine colostrum

Colostrum contains factors that are protective for the neonate and may be a source of immunomodulary molecules that positively influence the immune status of the neonate. To confirm that colostrum contains a variety of cytokines with immunomodulatory properties, we established a bovine cytokine specific ELISA and five cytokines (IL-1 beta, IL-6, TNF-alpha, INF-gamma or IL-1 receptor antagonist, IL-1ra) in the whey samples from cows at different stages of lactation were monitored. The expression of cytokine mRNAs (IL-1 beta, IL-6, TNF-alpha and INF-gamma) in the colostral cells was detected by RT-PCR. The concentrations of cytokines in colostrum were significantly higher concentrations than those in the mature milk. A positive correlation was observed between the concentrations of IL-1ra and IL-1 beta in the colostrum samples. In conclusion, colostrum contains high levels of cytokines that could be produced and secreted in the mammary gland and that may have an immunomodulatory activity and influence neonatal immunity.