Variation in protein metabolism biomarkers during the transition period and associations with health, colostrum quality, reproduction, and milk production traits in Holstein cows.

The aims of this study were to assess (1) the variation of protein metabolism biomarkers and factors affecting them during the transition period, (2) the association of each biomarker with skeletal muscle reserves and their changes, and (3) the association of these biomarkers with postpartum health, colostrum quality, reproduction, and milk production. For this purpose, 238 multiparous Holstein cows from 6 herds were used in a prospective cohort study. Plasma concentrations of 3-methylhistidine (3-MH) and 1-methylhistidine (1-MH) and serum concentrations of total protein (TP), albumin (ALB), urea nitrogen (BUN), and creatinine (SCR) were determined for each cow at -21, -7, 7, 21, and 28 d relative to calving. Clinical diseases were recorded during the first 28 d postcalving, and presence of subclinical ketosis (scKET) was investigated at 7 and 21 d. Colostrum quality was estimated by Brix refractometry. Reproduction data by 150 d in milk (DIM) and milk production records were also available. Linear mixed models including the fixed effects of time point, herd, parity, body condition score (-21 d), duration of dry period and postparturient diseases were fitted to assess the variation in each biomarker's concentration. The association between the biomarkers' concentration during the prepartum period with the odds for each postparturient disease and for a combined trait (CD_1-28), defined as the presence of at least one clinical condition during the first 28 d after calving, were assessed with separate binary logistic models for time points -21 d and -7 d. The relationship of each biomarker's concentration with longissimus dorsi thickness (LDT) and the changes in LDT (ΔLDT) was assessed with pairwise correlations. Separate general linear models were used to assess the association of each biomarker with colostrum Brix values and milk production traits. Finally, the associated hazard for first artificial insemination (AI) and for pregnancy by 150 DIM (PREG_150DIM) was assessed with Cox proportional hazard models, whereas odds for pregnancy to the first AI (PREG_1stAI) were assessed with binary logistic models. The level of 3-MH was affected mainly by herd, time points, and their interaction. Higher 3-MH was associated with increased odds for metritis and CD_1-28, increased hazard for PREG_150 DIM and with increased milk production. 1-Methylhistidine was affected mainly by herd, scKET and occurrence of displaced abomasum. Higher 1-MH was associated with better colostrum quality, increased odds for scKET, increased hazard for first AI by 150 DIM and with decreased milk production. Both 3-MH and 1-MH were weakly to moderately negatively correlated with LDT and moderately to strongly negatively correlated with ΔLDT at the corresponding time periods. Additionally, higher TP was associated with increased odds for metritis and CD_1-28 and increased milk production, while higher ALB was associated with increased odds for scKET and increased milk production. Moreover, higher BUN was associated with decreased odds for scKET, increased odds for PREG_1stAI and increased milk production. Higher SCR was associated with decreased odds for retained fetal membranes, metritis, and CD_1-28. Periparturient protein metabolism is significantly associated with postpartum health, colostrum quality, reproduction, and milk production; mechanisms involved require further investigation.

Skeletal muscle and adipose tissue reserves and mobilisation in transition Holstein cows: Part 1 Biological variation and affecting factors.

Nutrient deficit during the periparturient period leads to mobilisation of body energy and protein reserves. Research regarding fat reserves and mobilisation is extensive, while, on the contrary, investigation of muscle mobilisation during the periparturient period is limited. The aim of this cohort study was to simultaneously investigate the biological variation of skeletal muscle and subcutaneous fat reserves together with their mobilisation in transition Holstein cows of different herds, using ultrasonography, and to assess potential affecting factors. For this purpose, ultrasound measurements of longissimus dorsi muscle thickness (LDT) and backfat thickness (BFT) from 238 multiparous cows of six dairy farms were obtained at six time points across the transition period (from 21 days pre- to 28 days postpartum). Concentrations of serum creatinine and non-esterified fatty acids were determined in order to confirm the loss of muscle mass and adipose tissue, respectively. Cases of clinical postparturient diseases and subclinical ketosis (scKET) during the first 28 days postcalving were recorded. Cows mobilised on average 32.8% and 37.3% of LDT and BFT reserves, respectively. Large between-cow variation was observed for both the onset and the degree of mobilisation. Time point, initial body condition score and parity were the most important predictors of LDT variation. Cows diagnosed with metritis (MET) had lower LDT postpartum and mobilised more muscle depth compared to cows not diagnosed with MET. Initial BCS, time point, initial BW (estimated by heart girth measurement) and parity were the most important predictors of BFT variation. Cows diagnosed with MET mobilised more backfat between -7d and 7d compared to cows not diagnosed with MET. Cows with scKET mobilised more backfat between 7- and 21 days postpartum compared to healthy ones. Variation of subcutaneous fat and skeletal muscle reserves during the transition period was large and affected by herd and several cow-level factors.

Skeletal muscle and adipose tissue reserves and mobilisation in transition Holstein cows: Part 2 association with postpartum health, reproductive performance and milk production.

The aim of this study was, for the first time, to simultaneously assess the association of skeletal muscle and subcutaneous fat reserves and their mobilisation, measured by ultrasonography, with the incidence of specific postparturient health, reproduction, and milk production traits. For this purpose, ultrasound measurements of longissimus dorsi thickness (LDT) and backfat thickness (BFT) from 238 multiparous cows from 6 dairy farms were obtained at 6 time points during the transition period (from 21 days pre- to 28 days postpartum). In each case, LDT and BFT measurements at each time point and LDT and BFT mobilisation variables at each study period were assessed simultaneously. Cases of specific clinical postparturient diseases and subclinical ketosis were recorded. An additional disease trait was used, defined as the presence or absence of at least one clinical condition after calving (CD_1-28). The associated disease odds with LDT/BFT variables were assessed with binary logistic regression models. The associated hazard for 1st artificial insemination (AI) and for pregnancy by 150 days-in-milk (PREG_150DIM) was assessed with Cox proportional hazard models. Moreover, binary logistic models were used to assess the associated odds for pregnancy to 1stAI (PREG_1stAI). Finally, association with 30d, 100d and 305d milk yield was assessed with linear regression models. Increased muscle depth during transition was negatively associated with odds for metritis and CD_1-28, while associations with odds for subclinical ketosis were inconclusive. Moreover, increased LDT reserves were associated with greater hazard for 1st AI by 150 days-in-milk, but results were inconclusive regarding odds for PREG_1stAI. Increased LDT mobilisation was associated with increased odds for metritis. Increased BFT reserves were positively associated with odds for metritis, CD_1-28 and subclinical ketosis and with decreased hazard for PREG_150DIM. Increased BFT mobilisation was associated with increased odds for subclinical ketosis and with decreased odds for PREG_1stAI and decreased hazard for PREG_150DIM. Cows with moderate BFT reserves performed better. Finally, increased BFT mobilisation during -21d to -7d from parturition was associated with less milk by 30d and 100d. On the contrary, increased BFT mobilisation during -7d to 7d was associated with more milk by 305d. Metabolism of muscle and fat tissue during transition period was differently associated with different postparturient health, reproduction and milk production traits. In general, greater muscle mass and moderate fat reserves with limited muscle and fat mobilisation were associated with better performance.

Association of post-partum serum Ca patterns with reproduction in Holstein cows.

The objective of this study was to evaluate the effects of subclinical hypocalcemia (SCHCa) patterns on reproductive performance in dairy cows. In a prospective observational study 916 cows from 9 herds were blood sampled on DIMs 1, 2, 4 and 8; Ca concentration was measured with atomic absorption and SCHCa was defined as Ca ≤ 2.09 mmol/L. Cluster analysis revealed 2 normocalcemic (NORM and HIGH) and five hypocalcemic (SCH-1 to 5) clusters. Cows in cluster NORM (n = 151) had mean day-to-day serum Ca (DIMs 1-8) between 2.24 and 2.41 mmol/L, and cows in HIGH (n = 167) between 2.42 and 2.53 mmol/L. Cows in SCH-1 (n = 130) and SCH-2 (n = 102) had transient and mostly mild SCHCa on day 1 and day 2, respectively. Cows in SCH-3 (n = 123) had mostly severe SCHCa on days 1 and 2, extending to day 4. Cows in SCH-4 (n = 120) and SCH-5 (n = 145) had SCHCa which culminated on days 4 and 8, respectively. Information on reproductive outcomes including pregnancy status by 120 and 200 DIM and days open were retrieved from farm records. Median (±SE) days to 1st artificial insemination (AI) until 120 DIM estimated with Kaplan-Meier analysis for cows in SCH-3, SCH-4 and SCH-5 were 100.0 ± 7.2, 109.0 ± 6.6 and 120.0 ± 3.2, respectively, and were statistically significantly higher from those in NORM and HIGH (91.0 ± 3.4 and 87 ± 3.7, respectively). Mean days (±SE) to detected pregnancy until 200 DIM estimated with Kaplan-Meier analysis for cows in SCH-3 were 161.2 ± 4.8 and were statistically significantly higher from those in clusters NORM and HIGH (155.5 ± 4.2 and 151.6 ± 4.3, respectively). The association of Ca clusters with the odds of detected pregnancy for the 1st insemination until 120 and 200 DIM was evaluated with Linear Mixed Models. Odds for pregnancy by 120 DIM did not differ among clusters, however, cows in clusters SCH-3 and SCH-5 had lower odds for pregnancy by 200 DIM compared to HIGH (OR = 0.55, P = 0.02, and OR = 0.49, P = 0.004, respectively). Covariate adjusted survival curves generated by multivariable Cox proportional hazards model revealed that: a) clusters SCH-3 and SCH-5 had the highest (36% and 38%, respectively), while NORM and HIGH the lowest (16% and 17%, respectively) proportion of cows not inseminated for the 1st time by 120 DIM, b) compared to HIGH, cows in SCH-5 had a lower hazard of pregnancy by 120 DIM (HR = 0.42, P = 0.005), c) the proportion of open cows by 200 DIM for NORM and HIGH were 57% and 47%, respectively, while for SCH-3 and SCH-5 66% and 68%, respectively, and d) compared to HIGH, SCH-3 (HR = 0.54, P = 0.008) and SCH-5 (HR = 0.50, P = 0.001) presented the lowest hazard for pregnancy by 200 DIM. In conclusion, cows that during the entire first week after calving were continuously normocalcemic had the best reproductive performance, while those of SCH-3 and SCH-5 the worst.

Subclinical hypocalcaemia follows specific time-related and severity patterns in post-partum Holstein cows.

Hypocalcaemia is a common metabolic disorder of post-parturient dairy cows; enhancement of our knowledge regarding Ca dynamics would improve cow health and welfare. This study investigated the presence of time- and severity-related subclinical hypocalcaemia (SCHCa) patterns in Holstein cows after calving and their association with diseases during the first week of lactation. A total of 938 cows from nine herds were blood sampled on days 1, 2, 4 and 8 post-partum, and serum Ca concentration was measured with atomic absorption. Subclinical ketosis (serum ß-hydroxybutyrate≥1.2 mmol/L) and cases of retained foetal membranes, metritis (MET), mastitis, ketosis and displaced abomasum (DA) were recorded. Using receiver operating characteristic (ROC) analysis, the SCHCa cut-off was identified at serum Ca ≤ 2.09 mmol/L. Hierarchical and two-step cluster analysis classified cows to seven clusters based on test day cow Ca records and overall SCHCa status. Two clusters (NORM and HIGH) included 318 normocalcaemic cows and five clusters (SCH-1 to -5) those that were at least once subclinically hypocalcaemic (n = 620). A second ROC analysis was performed in order to distinguish mild from severe cases of SCHCa in these 620 cows; this cut-off was identified at 1.93 mmol/L. The associated risk of disease with Ca clustership was assessed with generalized linear mixed models. Overall incidence of SCHCa was 66.1%. Clusters SCH-1 and SCH-2 included cows with short-term SCHCa of day 1 and day 2, respectively, while SCH-3 included cows with severe and prolonged SCHCa extending to day 4 and beyond. Clusters SCH-4 and SCH-5 included cows with delayed SCHCa, which culminated on days 4 and 8, respectively. Compared to NORM cows in HIGH had lower risk of MET and no cases of DA. Cows in SCH-3 had higher risk of being diagnosed with retained foetal membranes, DA or any disease during the study period. Cows in SCH-5 had higher risk of being diagnosed with ketosis, subclinical ketosis or any disease. In conclusion, there are multiple normocalcaemic and hypocalcaemic patterns that are differently associated with disease risk.

Genetic parameters of colostrum traits in Holstein dairy cows.

The main objective of this study was to assess the genetic background of colostrum yield and quality traits after calving in Holstein dairy cows. The secondary objective was to investigate genetic and phenotypic correlations among laboratory-based and on-farm-measured colostrum traits. The study was conducted in 10 commercial dairy herds located in northern Greece. A total of 1,074 healthy Holstein cows with detailed pedigree information were examined from February 2015 to September 2016. All cows were clinically examined on the day of calving and scored for body condition. All 4 quarters were machine-milked, and a representative and composite colostrum sample was collected and examined. Colostrum total solids (TS) content was determined on-farm using a digital Brix refractometer. Colostrum fat, protein, and lactose contents were determined using an infrared milk analyzer, and energy content was calculated using National Research Council (2001) equations. Dry period length (for cows of parity ≥2), milk yield of previous 305-d lactation (for cows of parity ≥2), age at calving, parity number, season of calving, time interval between calving and first colostrum milking, and milk yield were recorded. Each trait (colostrum yield and quality traits) was analyzed with a univariate mixed model, including fixed effects of previously mentioned factors and the random animal additive genetic effect. All available pedigrees were included in the analysis, bringing the total animal number to 5,662. Estimates of (co)variance components were used to calculate heritability for each trait. Correlations among colostrum traits were estimated with bivariate analysis using the same model. Mean percentage (±SD) colostrum TS, fat, protein, and lactose contents were 25.8 ± 4.7, 6.4 ± 3.3, 17.8 ± 4.0, and 2.2 ± 0.7%, respectively; mean energy content was 1.35 ± 0.3 Mcal/kg and mean colostrum yield was 6.18 ± 3.77 kg. Heritability estimates for the above colostrum traits were 0.27, 0.21, 0.19, 0.15, 0.22, and 0.04, respectively. Several significant genetic and phenotypic correlations were derived. The genetic correlation of TS content measured on-farm with colostrum protein was practically unity, whereas the correlation with energy content was moderate (0.61). Fat content had no genetic correlation with TS content; their phenotypic correlation was positive and low. Colostrum yield was not correlated genetically with any of the other traits. In conclusion, colostrum quality traits are heritable and can be amended with genetic selection.

Genetic parameters of subclinical macromineral disorders and major clinical diseases in postparturient Holstein cows.

The main objective of this study was to assess the genetic parameters of subclinical disorders associated with subclinical hypocalcemia, hypophosphatemia, subclinical hypomagnesemia, hypokalemia, and hyperphosphatemia, as well as major clinical diseases after calving in Holstein cows. The secondary objective was to estimate the associated genetic and phenotypic correlations among these subclinical and clinical conditions after calving in Holstein cows. The study was conducted in 9dairy herds located in Northern Greece. None of the herds used any kind of preventive measures for milk fever (MF). A total of 1,021 Holstein cows with pedigree information were examined from November 2010 until November 2012. The distribution across parities was 466 (parity 1), 242 (parity 2), 165 (parity 3), and 148 (parity 4 and above) cows. All cows were subjected to a detailed clinical examination and blood was sampled on d 1, 2, 4, and 8 after calving. Serum concentrations of Ca, P, Mg, and K were measured in all samples, whereas ß-hydroxybutyrate (BHB) was measured only for d 8. The final data set included 4,064 clinical and 16,848 biochemical records (4,020 Ca, 4,019 P, 4,020Mg, 3,792K, and 997 BHB). Data of 1,988 observations of body condition score at d 1 and 8 were also available. All health traits were analyzed with a univariate random regression model. The genetic analysis for macromineral-related disorders included 986 cows with no obvious signs of MF (35 cows with MF were excluded). Analysis for other health traits included all 1,021 cows. A similar single record model was used for the analysis of BHB. Genetic correlations among traits were estimated with a series of bivariate analyses. Statistically significant daily heritabilities of subclinical hypocalcemia (0.13-0.25), hypophosphatemia (0.18-0.33), subclinical hypomagnesemia (0.11-0.38), and hyperphosphatemia (0.14-0.22) were low to moderate, whereas that of hypokalemia was low (0.08-0.10). The heritability of body condition score was 0.20±0.10. Statistically significant daily heritabilities of clinical diseases were those of MF (0.07-0.11), left displaced abomasum (0.19-0.31), and mastitis (0.15-0.41). Results suggest that these health disorders are heritable traits and could be minimized with proper genetic selection. Statistically significant phenotypic correlations were estimated for the first time between macromineral concentrations and almost all transition cow metabolic and infectious health disorders.

Genetic parameters of calcium, phosphorus, magnesium, and potassium serum concentrations during the first 8 days after calving in Holstein cows.

Calcium, Mg, P, and K are of great importance for the health and productivity of dairy cows after calving. So far genetic studies have focused on clinical hypocalcemia, leaving the genetic parameters of these macroelements unstudied. Our objective was to estimate the genetic parameters of Ca, Mg, P, and K serum concentrations and their changes during the first 8d after calving. The study was conducted in 9 herds located in northern Greece, with 1,021 Holstein cows enrolled from November 2010 until November 2012. No herd used any kind of preventive measures for hypocalcemia. Pedigree information for all cows was available. A total of 35 cows were diagnosed and treated for periparturient paresis and, therefore, excluded from the study. The remaining 986 cows were included in genetic analysis. The distribution of cows across parities was 459 (parity 1), 234 (parity 2), 158 (parity 3), and 135 (parity ≥4). A sample of blood was taken from each cow on d1, 2, 4, and 8 after calving and serum concentrations of Ca, P, Mg, and K were measured in each sample. A final data set of 15,390 biochemical records was created consisting of 3,903 Ca, 3,902 P, 3,903Mg, and 3,682K measurements. Moreover, changes of these concentrations between d1 and 4 as well as 1 and 8 after calving were calculated and treated as different traits. Random regression models were used to analyze the data. Results showed that daily heritabilities of Ca, P, and Mg concentrations traits were moderate to high (0.20-0.43), whereas those of K were low to moderate (0.12-0.23). Regarding concentration changes, only Mg change between d1 and 8 after calving had a significant heritability of 0.18. Genetic correlations between Ca, P, Mg, and K concentrations and their concentration changes from d1 to 4 and 1 to 8 after calving were not significantly different from zero. Most phenotypic correlations among Ca, P, Mg, and K concentrations were positive and low (0.09-0.16), whereas the correlation between P and Mg was negative and low (-0.16). Phenotypic correlations among macromineral concentrations on d1 and their changes from d1 to 4 and 1 to 8 after calving varied for each macromineral. This study revealed that genetic selection for normal Ca, P, Mg, and K concentrations in the first week of lactation is possible and could facilitate the management of their deficiencies during the early stages of lactation.

Evaluation of Precision Xceed® meter for on-site monitoring of blood ß-hydroxybutyric acid and glucose concentrations in dairy sheep.

The accuracy of the Precision Xceed® hand-held meter as an on-site method for measuring blood ß-hydroxybutyric acid (BHBA) and glucose concentrations, for the diagnosis of pregnancy toxemia and ketosis in dry and lactating dairy sheep, was assessed. Five to eight hours after the start of the morning feed, blood was collected once from 193 clinically healthy sheep (143 dry and 50 lactating). BHBA and glucose analyses were performed with serum in the laboratory, and with whole blood with the Precision Xceed®. Overall, BHBA and glucose determinations by the two methods were not statistically different (P>0.05). Strongly significant positive correlations were found for glucose and BHBA concentrations between the Precision Xceed® and laboratory results (r=0.76, n=150, P<0.01 and r=0.99, n=193, P<0.01, respectively). The Precision Xceed® was highly sensitive (98.6%) and specific (98.2%), and had excellent test agreement for the detection of pregnancy toxemia and ketosis.

Macromineral status of dairy cows with concurrent left abomasal displacement and fatty liver.

AIM: To evaluate the macromineral status of field cases of dairy cows surgically treated for left abomasal displacement (LDA), with concurrent fatty liver of different severity, and compare this for animals that died or recovered. METHODS: Sixty-eight Holstein dairy cows with LDA and 110 control cows, from 28 farms, were used in the study. Blood samples and liver biopsies were obtained during standing surgery for correction of LDA, and from control cows. The concentration of macrominerals in serum, and of total lipids (tLPD) and triglycerides (TG) in liver were determined. Liver was examined histologically, and classified for its severity of fatty liver. Cows with LDA were grouped according to severity of fatty liver. Cows in Groups 1 to 3 recovered, whereas those in Group 4 died within 4 weeks of surgery. Group 1 = mild (n=4) or moderate (n=6 cows, n=4 heifers) fatty liver, Group 2 = moderate to severe fatty liver (n=13), Group 3 = severe fatty liver (n=15 cows, n=5 heifers), Group 4 = severe fatty liver (n=17 cows, n=4 heifers). RESULTS: The concentration of macrominerals in serum was affected by the concurrence of fatty liver and LDA; Ca, K and Mg were significantly (p<0.05) lower in animals that died than those that survived. For cows with severe fatty liver, concentrations of tLD and TG were higher in the animals that died compared with those that recovered (p<0.01). Cows with LDA and severe fatty liver that died were earlier in lactation (median days in milk (DIM) 13 days) compared with the other cows with LDA (median DIM 21-26 days) (p<0.05); they were also significantly older (median 6 years old) than cows in the other groups (median 4 or 5 years old) (p<0.05). CONCLUSIONS AND CLINICAL RELEVANCE: Concentrations of macrominerals in serum were influenced by the concurrence of LDA and fatty liver. Animals with low concentrations of Ca, K and Mg had a guarded prognosis. The concentration of K should always be evaluated in cows with LDA and concurrent fatty liver when providing a prognosis. Most cows with severe fatty liver were detected in the first 4 weeks of lactation, but older animals and those that had more recently calved had a worse prognosis.

Factors affecting the reproductive performance of Awassi sheep flocks in north-east of Jordan: an epidemiological study.

A prospective cohort study was conducted using 32 randomly selected Awassi sheep flocks to identify factors hypothesized to be associated with the occurrence of pregnancy, twinning and fetal loss between August 2005 and May 2006 in the region of Al-Safawi (northeast of Jordan). Vitamins A and E and selenium concentrations were determined on 448 blood samples. Using the forward selection procedure of the logistic regression module, models with statistically significant risk factors (P < 0.05) were constructed for three outcomes; pregnancy, twinning and fetal loss. Serum vitamin A concentration levels were associated with pregnancy (OR = 2.26, 2.48), twinning (OR = 6.49, 17.74) and fetal loss (OR = 0.13, 0.19). Primiparous ewes were 48% less likely to become pregnant than fourth or higher parity ewes. The likelihood of twinning increased significantly in ewes up to the third parity. Ewes that were fed 700-900 g barley, 250-300 g wheat-bran per head per day and grazed on vegetables residues were 4.15 times more likely to have twins than ewes that were fed 600 g barley and 200 g wheat-bran per head per day. Fetal loss in first and second parity ewes was about 3 times more likely than that in third or higher-parity ewes. Ewes pregnant with twins were about 14 times more likely to have fetal loss than ewes carrying single fetus. Pregnant ewes of the stationary flocks were 37% less likely to have fetal loss than ewes of the semi-nomadic flocks. These results demonstrate that stationary Awassi sheep flocks had higher pregnancy and twinning rates and less pregnancy loss. Supplementation of vitamin A, providing sufficient quantity of dry feed and increasing ram: ewe ratio for primiparous ewes of semi-nomadic flocks is essential to improve Awassi sheep reproductive performance.

Effect of halofuginone lactate on treatment and prevention of lamb cryptosporidiosis: an extensive field trial.

This study aimed to investigate the effects of halofuginone lactate (100 mug/kg BW) on treatment and prevention of cryptosporidiosis in lambs. It consisted of three field trials. The first trial was designed to assess the efficacy of halofuginone in treating lamb diarrhoea caused by cryptosporidiosis, and in preventing the disease, using two schemes; halofuginone given for seven and for three consecutive days respectively. Halofuginone was effective in the treatment of diarrhoea caused by cryptosporidiosis (P < 0.01). In addition, halofuginone administered as a 7-day treatment was significantly (P < 0.05) more effective than a 3-day treatment in preventing diarrhoea in the infected flocks. The second trial was designed to evaluate the preventive effect of halofuginone, which was administered for 7 days in lambs infected with cryptosporidiosis, on diarrhoea incidence, oocyst shedding and body weight gain. Halofuginone significantly (P < 0.01) reduced the diarrhoea incidence, the time of oocyst shedding and the mean intensity of shedding, but did not affect body weight gain. The third trial was designed to examine the ability of halofuginone to reduce the death rate in flocks with cryptosporidiosis. Halofuginone treatment was effective in preventing and in reducing the death rate of cryptosporidiosis in these flocks.

Selenium, vitamin E and vitamin A status in dairy sheep reared under different feeding systems in Greece.

The main purpose of the study was to investigate whether the feeding system applied has any effect on the status of blood selenium (Se) and vitamins A and E in dairy sheep. In total 200 dairy sheep from 10 flocks were used in the study (20 animals per flock). Group A consisted of 100 sheep (five flocks) reared under the intensive feeding system and group B of 100 sheep (five flocks) reared under the semi-intensive feeding system. The 100 sheep of each group consisted of 25 lambs aged 3-6 months, 25 ewes 1-3 years, 25 ewes more than 3 years and 25 non-lactating ewes in late gestation. Another purpose was to evaluate the potential effect of the age and the reproductive stage of the animals on these parameters. To determine the effect of age, 150 of these animals were divided into three subgroups: 50 lambs, 50 non-pregnant lactating ewes aged 1-3 years and 50 non-pregnant lactating ewes aged more than 3 years. For the evaluation of the effect of the reproductive stage the 50 non-lactating ewes in late gestation and the 100 non-pregnant lactating ewes were used. Blood samplings were performed once, between December and January for non-lactating ewes in late gestation and March to May for lambs and lactating ewes. Whole blood Se and vitamin E and A serum concentrations were determined. The main conclusion is that the feeding system significantly affects Se and serum vitamin A concentration, as they were higher in the intensive one. It was secondly concluded that age affects the serum concentrations of vitamin A.

Effects of long-term feeding of a diet supplemented with clinoptilolite to dairy cows on the incidence of ketosis, milk yield and liver function.

Fifty-two clinically healthy Holstein cows were randomly assigned to one of three groups according to their age and parity. The first group (A) consisted of 17 cows that were fed a concentrate ration supplemented with 1.25 per cent clinoptilolite, the second group (B) consisted of 17 cows fed a ration supplemented with 2.5 per cent clinoptilolite, and the third group (C) consisted of 18 cows, which were fed the basal ration containing no clinoptilolite. The rations were fed from four weeks before the cows' expected parturition dates until the beginning of the next dry period. Blood samples were collected from each animal at the start of the experiment, on the day of calving and then monthly, and analysed for serum glucose, ketone bodies, liver enzymes, blood urea nitrogen (BUN) and total proteins. The milk yield of each cow was recorded monthly. The cows in group B had significantly fewer cases of clinical ketosis during the first month after calving and a higher total milk yield. Feeding the cows with clinoptilolite for a long period had no apparent adverse effects on their liver function, and did not significantly affect the concentrations of glucose, ketone bodies, BUN and total proteins in their serum.

Effects of age and reproductive stage on certain serum biochemical parameters of chios sheep under greek rearing conditions.

The aim of the present study was to determine the normal ranges of the most commonly used serum biochemical parameters of sheep reared under Greek breeding conditions, as well as to test for the effects of the age and reproductive status of the animals on the normal values of these parameters. In total, 200 clinically healthy Chios sheep from 10 farms were used in the experiment. For the determination of the effect of age 150 sheep were assigned in three groups. Group A consisting of 50 lambs aged 2-6 months (mean +/- SD: 4.15 +/- 1.08), group B of 50 non-pregnant ewes into lactation aged 1-3 years (mean +/- SD: 2.12 +/- 0.86) and group C of 50 non-pregnant ewes into lactation aged more than 3 years (mean +/- SD: 5.98 +/- 1.66). For evaluating the effect of reproductive status 50 pregnant ewes in dry period were used, 15-30 days before the expected day of lambing (group D), along with the 100 non-pregnant ewes into lactation of groups B and C (group E). Blood sampling was performed once, in dry ewes from December to January, and in lambs and lactating ewes from March to May. The results showed that of the 14 biochemical parameters determined in serum, six were significantly affected by the age and eight by the reproductive stage of the animals.

Effects of long-term feeding dairy cows on a diet supplemented with clinoptilolite on certain serum trace elements.

The objective of the experiment was to investigate the effect of clinoptilolite (a natural zeolite) supplementation in the ration of dairy cows on serum copper (Cu), zinc (Zn), and iron (Fe) concentrations. Fifty-two clinically healthy Holstein cows were randomly assigned to one of three groups according to their age and parity. The first group (group A) comprised 17 cows fed a ration supplemented with 1.25% clinoptilolite, the second group (group B) comprised also 17 cows was given a ration with 2.5% clinoptilolite, and the third group (group C, the control), comprised 18 cows fed the basal ration that did not contain any clinoptilolite. The experiment started when the cows entered the fourth week before the expected parturition and lasted until the end of lactation. All cows were fed the above concentrates during the entire experimental period. Blood samples were collected from each animal at the starting day of the experiment, at the day of calving, and at monthly intervals thereafter. All samples were tested for serum Cu, Zn, and Fe concentrations. The results showed that the 1.25 and 2.5% supplementation of clinoptilolite did not have any adverse effects on serum concentrations of Cu, Zn, and Fe.

Long-term fluctuations and effect of age on serum concentrations of certain fat-soluble vitamins in dairy cows.

BACKGROUND: There is insufficient evidence in the literature concerning the fluctuations and correlations of serum fat-soluble vitamin concentrations during lactation in dairy cows and the potential effect of age of the animals on these values. OBJECTIVES: The objectives of this study were to determine fluctuations in mean serum concentrations of the fat-soluble vitamins A and E and b-carotene and the correlations among them in clinically healthy dairy cows, from the last month of the dry period until the end of lactation, and to investigate whether age was a factor that affects these serum concentrations. METHODS: Forty-five clinically healthy Holstein cows were assigned to 2 groups based on age. Group A consisted of 23 cows 4 years old (mean +/- SD, 3.24 +/- 0.44 years), and group B consisted of 22 cows >4 years old (6.68 +/- 1.66 years). Blood samples for determination of serum beta-carotene, vitamin A, and vitamin E concentrations were collected from each animal just before the start of study (1 month prior to expected parturition), at parturition, and thereafter, at monthly intervals until the end of lactation. RESULTS: There was a significant positive correlation between beta-carotene, vitamin A, and vitamin E values. Mean serum concentrations of beta-carotene, vitamin A, and vitamin E were significantly higher in younger animals. CONCLUSIONS: To our knowledge, this is the first evidence that age is a factor affecting serum concentrations of fat-soluble vitamins in dairy cows.

Effects on blood concentrations of certain serum fat-soluble vitamins of long-term feeding of dairy cows on a diet supplemented with clinoptilolite.

The objective of the experiment was to investigate the effect of clinoptilolite (a natural zeolite) supplementation in the ration of dairy cows on serum beta-carotene, vitamins A and E concentrations. Fifty-two clinically healthy Holstein cows were randomly assigned to one of three groups according to their age and parity. The first group (group A, n = 17), was offered a concentrate feed supplemented with 1.25% clinoptilolite. The second group (group B, n = 17), was offered a concentrate feed supplemented with 2.5% clinoptilolite. The third group (group C, n = 18), which served as controls, was offered the same concentrate feed without clinoptilolite supplementation. All cows were fed the above concentrates continuously starting 30 days before the expected parturition up to the end of lactation. Blood samples from individual animals were collected just before the start of experiment, at the day of calving and, thereafter, at monthly intervals. All samples were tested for serum beta-carotene, vitamins A and E concentrations. The results showed that the 1.25 and 2.5% supplementation of clinoptilolite had no adverse effect on serum concentrations of beta-carotene, vitamins A and E.