Immunological and bacteriological quality of fresh cow colostrum and passive immunity transfer in selected dairy farms in Fars, Iran.

Background: The quality of colostrum is affected by IgG level and microbial load. Aims: The quality of colostrum used in feeding dairy calves and passive immunity transfer in selected dairy farms in Fars province, Iran was investigated. Methods: A total of 75 colostrum and neonatal blood samples were collected from 11 herds. The immunological quality of colostrum was assessed using a Brix digital refractometer. The bacteriological quality was assessed by performing total plate count (TPC), total coliform count (TCC), spore-former count, fungi count, and species-specific PCR assay to detect some bacterial species. Results: The mean Brix of colostrum samples was 25.4% and 72% of the samples had a Brix score ≥22%. The mean serum Brix and the prevalence of failure of passive transfer (FPT) were 10% and 4%, respectively. The mean TPC, TCC, spore-former count, and fungi count were 3.6 × 105, 2.8 × 104, 3.2 × 104, and 1.1 × 104 CFU/ml, respectively. The results showed that 50, 5.9, and 4% of colostrum samples were positive for Staphylococcus spp., Salmonella spp. and Maycobacterium paratuberculosis, respectively. There was no evidence of contamination with Brucella spp., Corynebacterium bovis and Mycoplasma bovis. Conclusion: Considering all colostrum quality indicators comprehensively, only 37.3% of the studied samples met the industry standard. A large number of calves were at risk of receiving poor quality colostrum, especially in terms of microbial contamination. Further researches are needed to evaluate the colostrum management and the effect of bacterial contamination of colostrum on the health of neonate calves in this region.

Alteration of fatty acid profile of milk in Holstein cows fed Bacillus coagulans as probiotic: a field study.

BACKGROUND: Probiotics may improve milk quality and the general health status of animals. AIMS: The effects of dietary Bacillus coagulans PRM101 on milk components, milk fatty acids (FA), and some health indicators of dairy cows were investigated. METHODS: The probiotic was added to the feed of 12 Holstein cows (2 g/cow: 2 × 1011 CFU/cow) for 63 days compared to a control group fed on the basal ration (n=11). Milk and blood samples were taken on days 0, 21, 42, and 63. RESULTS: The yields of milk and energy corrected milk (ECM; computed from milk weight and its fat and protein content) decreased linearly and similarly (P=0.60) in both groups. The treatment cows, however, showed quadratic increases in the weights of milk (P=0.03) and ECM (P=0.04) at d42 of the study. Energy corrected milk (d42, P<0.05) and crude protein content of milk (d42, P<0.05; d63, P<0.1) were higher in the cows receiving the probiotic. The proportions of heptadecanoic (C17:0; P=0.002) and linoleic (C18:2; P=0.077) acids in milk fat (g/100 g fat) were higher in the treatment cows on d63. Milk total antioxidant capacity (TAC), malondialdehyde (MDA), and similarly, amyloid A (AA) and haptoglobin (Hp) of milk and blood were not affected. Total antioxidant capacity and MDA were negatively correlated in the control group (r=-0.669, P=0.005). Heptadecanoic acid correlated negatively with milk MDA (r=-0.611, P=0.035) and positively (r=0.591, P=0.043) with serum Hp in the treatment cows. CONCLUSION: Dietary B. coagulans PRM101 may improve the proportions of C17:0 and C18:2 FA in milk. Some improvements in milk protein and the health status of the cows may also be anticipated.

Compromised liver functions during the breeding period of clinically healthy Holstein cows.

BACKGROUND: The sub-clinical carry-over effects of post-partum (PP) conditions and the problems independent of parturition may affect the cows' performance during the breeding period. AIMS: It was hypothesized that some mid-lactation cows may have compromised liver functions and calculating liver activity index (LAI; -1.5 to +1.5) may be helpful in detecting such conditions. METHODS: Plasma lipid and protein profiles, retinol and ceruloplasmin were measured in 37 Holstein cows on days 60, 90, and 120 PP. Liver activity index was calculated using the measures of cholesterol, albumin and retinol. The results were interpreted using some health and performance indices. RESULTS: The mean LAI was 0.00 ± 0.61. Sixteen cows (45.7%) were LAI‾ and 19 cows (54.3%) were LAI+. In LAI+ cows the concentrations of cholesterol and albumin were unchanged, but in LAI‾ cows both of them increased through the study (P<0.05). Greater concentrations of low density lipoproteins (LDL) (P<0.01) and lower concentrations of γ- and total globulins (P<0.05; day 60) were detected in LAI+ cows. Ceruloplasmin was not different between the LAI groups with the highest level on day 90. Cholesterol had the strongest and the most repeated correlations with LAI during the study. The correlation of albumin with LAI faded on day 120 and vitamin A had a relationship only on day 60 PP. Triglycerides (TGs), very low density lipoproteins (VLDL) (day 60) and LDL (days 60 and 90) had positive correlations with LAI. All globulin fractions showed negative correlations with LAI on day 60. Seventy percent of the cows without endometritis (day 30 PP) and 33% of the infected cows were LAI+ during the breeding period. About 79% of the cows with body condition score (BCS) loss ≤0.75 (day 60) and 38% of the cows with BCS loss >0.75 were LAI+ during the breeding period. CONCLUSION: Compromised liver functions may exist in dairy cows during the breeding period and may be detected by calculating LAI. The relationship of LAI during the progressed lactation with herd's performance needs to be investigated.

A field study on glucose, non-esterified fatty acids, beta-hydroxybutyrate and thyroid hormones in dairy cows during the breeding period in Fars province, Iran.

BACKGROUND: It was hypothesized that under apparently good management practices in dairy farms, some cows may not be metabolically perfect during the breeding period and this may affect their performance. AIMS: This study was conducted to assess probable metabolic drawbacks in mid-lactation dairy cows affecting their performance. METHODS: Thirty-seven clinically healthy Holstein cows were assessed for plasma concentrations of glucose, non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), thyroxin (T4), and tri-iodothyronine (T3) on days 60, 90 and 120 of lactation. The relationships of the measured analytes with some performance indices were also studied. RESULTS: Continuous declines in plasma glucose (within reference values; P<0.006), T4 (P<0.001) and T3 (0.003) were found during the study. Non-esterified fatty acids showed relatively high levels through the study with a rise at day 90 (P<0.041). Beta-hydroxybutyrate concentrations did not change significantly (P>0.05) but were higher than those reported by others in mid-lactation cows. By progress in lactation 27% of cows had glucose concentrations <2.5 mmol/L, 62% had NEFA concentrations >0.40 mmol/L and 13.5% had BHB levels above 1200 µmol/L, which are the threshold levels of peri- and post-parturient problems. Milk production had negative correlations with glucose and T4 while the correlation was positive with NEFA. The interval between calving to the 1st heat had positive correlations with BHB concentrations. The interval between calving and the 1st insemination was inversely correlated with glucose and positively correlated with NEFA levels. CONCLUSION: The changes of the studied analytes in mid-lactation cows resembled those that would happen during negative energy balance in early lactation cows and feed restriction in mid-lactation cows and may affect the general health and the performance of the cows.

The effects of post-partum drops in body condition on indices of energy metabolism in mid-lactation Holstein cows.

BACKGROUND: Evaluation of energy metabolism indices in mid-lactation Holstein cows is critical to monitor health status. Aims: The objective of this study was to assess the effects of low (≤0.75) vs. high (>0.75) drops in body condition score (BCS) until day 60 post-partum on energy metabolism indices during mid-lactation in Holstein cows. METHODS: Twenty-eight Holstein cows were included in the study from the day of calving to day 120 of lactation. Whole blood samples were taken on 60, 90, and 120 days in milk (DIM). Serum was analyzed for insulin, glucose, non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) levels. RESULTS: In cows with low BCS drop (LoD group), insulin did not change significantly through days 60 to 120 of lactation, but increased in high drop cows (HiD group) (P<0.001). Glucose concentrations decreased linearly in the LoD cows (P=0.039) and showed a quadratic increase in the HiD group on day 90 (P=0.028). Concentrations of non-esterified fatty acids showed both linear (P=0.04) and quadratic (P=0.002) changes in the HiD group. The HiD cows had significantly higher concentrations of insulin on day 120 (P=0.017) compared to the LoD group. Glucose concentration was lower (P<0.01) in HiD cows on 60 DIM. The concentration of non-esterified fatty acids was higher in HiD cows on day 90 (P<0.01). Surrogate indices of insulin resistance (calculated based on the concentrations of the measured metabolites) were different between the groups on day 90, indicating decreased insulin sensitivity in the HiD cows. CONCLUSION: Greater depletion of body reserves during early lactation may result in some inconsistencies in energy metabolism during mid-lactation periods. Controlling BCS loss during early lactation may help alleviate such alterations possibly through modifying insulin sensitivity of the tissues.

Progesterone concentration and lambing rate of Karakul ewes treated with prostaglandin and GnRH combined with the ram effect during breeding and non-breeding seasons.

The combination of ram effect with two injections of PGF2α 10-days apart and the same protocol plus an additional injection of GnRH prior to the first injection of PGF2α were examined in Karakul ewes during breeding and non-breeding seasons, respectively. Plasma progesterone (P4) concentrations (to detect the presence of active corpus luteum), twin lambing, litter size and synchronization of lambing were evaluated. In each study 70 ewes (2-4 years old) were divided to a treatment (n = 40) and a control (n = 30) group. During the breeding season, on days -10 and 0 before ram release, the treatment group was injected intramuscularly with PGF2α (D-Cloprostenol; 0.15 mg). During the non-breeding season, on day -15 before ram release the treatment group was injected with GnRH (buserelin; 4.2 µg) intramuscularly followed by two injections of PGF2α on days -10 and 0. In both studies, the rams were released into the ewe flock after the second prostaglandin injection (day 0). Blood samples of ewes were collected on days -10, 0, 20 and 70 of the study in breeding season and on days -15, -10, 0, 20 and 70 during non-breeding season. The treatment group had higher P4 concentrations compared to the control ewes on day 0 in the breeding season (5.80 ± 0.61 vs. 5.0 ± 0.93 ng/mL) and day -10 in the non-breeding season (3.50 ± 0.33 vs. 2.70 ± 0.35 ng/mL) though the differences were not significant (P > 0.05). Based on plasma P4 concentrations (>1 ng/mL) on day 70, in the breeding season all control ewes (100%) and 91.9% of the treatment ewes were detected to have active corpus luteum (P = 0.09). An almost inverse result (90% vs. 97.5%; P = 0.2) was detected in the non-breeding season. The lambing rate was higher (P = 0.03) in the treatment group compared to the control ewes during the non-breeding season (90% vs. 70%), but tended to be lower (P = 0.07) in the breeding season (73% vs. 90%). Twin lambing rate was higher in the treatment group compared to the control ewes in the breeding (40.7% vs. 0.0%; P < 0.05) and non-breeding (22.2% vs. 0.0%; P < 0.05) seasons. The litter size of the control and treated ewes were 1.0 ± 0.0 vs. 1.40 ± 0.10 in the breeding and 1.0 ± 0.0 vs. 1.22 ± 0.10 in the non-breeding season (P < 0.05). No effect was observed regard to synchronization of the treated ewes. In the breeding season two injections of PGF2α ten days apart combined with ram effect, may lower the lambing rate, but may enhance twin pregnancies and litter size in Karakul ewes. In the non-breeding season, however, the GnRH-PGF2α treatment plus ram effect may enhance the lambing rate, twin pregnancies and litter size.

Effect of monensin on serum lipoproteins, triglycerides, cholesterol and total lipids of periparturient dairy cows.

Serum concentrations of very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), high-density lipoproteins (HDL), triglycerides, cholesterol, and total lipids of a group of monensin-treated cows (n = 7) were compared with those of a control group (n = 6) from about 10 days before calving to 45 days postpartum. Monensin was fed in the diet from about 20 days before predicted calving date to 45 days after parturition. Blood samples were obtained on days 20 and 10 before predicted calving, and on days 4, 15, 25 (phase I), and days 35 and 45 (phase II) post calving. Cholesterol (p = 0.046) and total lipids (p = 0.003) were lower in the treatment group 10 days before calving. Concentrations of serum triglycerides and VLDL (p = 0.017), and that of LDL (p = 0.032) were significantly higher in the treatment group in phase I postpartum. No significant difference was detected between groups during phase II. Comparison of the entire length of the trial showed higher concentrations of triglycerides and VLDL in the treatment group (p = 0.009). It is concluded that monensin is effective in increasing secretion of triglyceride-rich lipoproteins from the liver during the postpartum transition period of dairy cows. This may be effective in reducing the intensity of hepatic lipidosis and the incidence of periparturient diseases resulting from disturbances in energy metabolism.

Primary evaluation of methenamine as a NPN compound with probable effects on increasing ruminal escaped protein.

The effects of methenamine as a non-protein nitrogenous compound on protein and health status of feedlot lambs were studied in three groups of lambs receiving 5, 10, or 15 g of the substance daily in their feed for 100 days. The results were compared with data obtained from a control group receiving a diet low in crude protein without methenamine. Serum total protein, serum urea nitrogen and serum creatinine were measured every 10 days as indicators of protein metabolism and kidney function. Urine samples were also examined on the same days for possible side-effects of methenamine on the urinary tract. Following slaughter, various internal organs, including the brain and various parts of the gastrointestinal and urinary tracts, were examined both grossly and microscopically to detect any lesions. All groups receiving methenamine had serum total protein and serum urea nitrogen levels higher than those in the control group. The serum creatinine level was normal in all the groups throughout the experiment. No gross or microscopic lesion attributed to the toxic effects of methenamine was detected in any of the internal organs. Therefore, it is concluded that methenamine can be used as a non-protein nitrogenous compound without serious side-effects.