This review paper provides an in-depth analysis of three critical metabolic diseases affecting dairy cattle such as subacute ruminal acidosis (SARA), ketosis, and hypocalcemia. SARA represents a ...disorder of ruminal fermentation that is characterized by extended periods of depressed ruminal pH below 5.5-5.6. In the long term, dairy herds experiencing SARA usually exhibit secondary signs of the disease, such as episodes of laminitis, weight loss and poor body condition despite adequate energy intake, and unexplained abscesses usually 3-6 months after an episode of SARA. Depressed milk-fat content is commonly used as a diagnostic tool for SARA. A normal milk-fat test in Holstein dairy cows is >4%, so a milk-fat test of <3% can indicate SARA. However, bulk tank testing of milk fat is inappropriate to diagnose SARA at the herd level, so when >4 cows out of 12 and <60 days in milk are suspected to have SARA it can be considered that the herd has a problem. The rapid or abrupt introduction of fresh cows to high-concentrate diets is the most common cause of SARA. Changes in ruminal bacterial populations when exposed to higher concentrate rations require at least about 3 weeks, and it is recommended that concentrate levels increase by no more than 400 g/day during this period to avoid SARA. Ketosis, a prevalent metabolic disorder in dairy cattle, is scrutinized with a focus on its etiological factors and the physiological changes leading to elevated ketone bodies. In total mix ration-fed herds, an increased risk of mastitis and reduced fertility are usually the first clinical signs of ketosis. All dairy cows in early lactation are at risk of ketosis, with most cases occurring in the first 2-4 weeks of lactation. Cows with a body condition score ≥3.75 on a 5-point scale at calving are at a greater risk of ketosis than those with lower body condition scores. The determination of serum or whole blood acetone, acetoacetate, beta-hydroxybutyrate (BHB) concentration, non-esterified fatty acids (NEFA), and liver biopsies is considered the best way to detect and monitor subclinical ketosis, while urine or milk cowside tests can also be used in on-farm monitoring programs. Concentrations >1.0 mmol/L or 1.4 mmol/L blood or serum BHB are considered diagnostic of subclinical ketosis. The standard threshold used for blood is 1.2 mmol/L, which corresponds to thresholds of 100 mcmol/L for milk and 15 mg/dL for urine. Oral administration of propylene glycol (250-400 g, every 24 h for 3-5 days) is the standard and most efficacious treatment, as well as additional therapy with bolus glucose treatment. Hypocalcemia is a disease of adult dairy cows in which acute hypocalcemia causes acute to peracute, afebrile, flaccid paralysis that occurs most commonly at or soon after parturition. Dairy cows are at considerable risk for hypocalcemia at the onset of lactation, when daily calcium excretion suddenly increases from about 10 g to 30 g per day. Cows with hypocalcemia have a more profound decrease in blood calcium concentration-typically below 5.5 mg/dL. The prevention of parturient paresis has been historically approached by feeding cows low-calcium diets during the dry period. Negative calcium balance triggers calcium mobilization before calving and better equips the cow to respond to the massive calcium needs at the onset of lactation. Calcium intake must be limited to <20 g per day for calcium restriction to be effective. The most practical and proven method for monitoring hypocalcemia is by feeding cows an acidogenic diet for ~3 weeks before calving. Throughout the review, emphasis is placed on the importance of early diagnosis and proactive management strategies to mitigate the impact of these metabolic diseases on dairy cattle health and productivity. The comprehensive nature of this paper aims to serve as a valuable resource for veterinarians, researchers, and dairy farmers seeking a deeper understanding of these prevalent metabolic disorders in dairy cattle.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The subject of this study is the validation of a high-performance liquid
chromatography method for the analysis of amino acids in feed. The contents
of amino acids were determined in maize, soybean, ...soybean meal, as well as in
their mixtures enriched with different amounts of methionine, threonine and
lysine. The method involves the acid hydrolysis of the sample (6 h at 150?C),
automated derivatisation of amino acids with the aid of o-phthaldialdehyde
and 9-fluorenylmethyl chloroformate reagents, separation on the ZORBAX
Eclipse-AAA column, and detection using a diode-array detector. The method is
characterized by high specificity (the difference between the retention times
of the feed samples and standard mixtures are below 1.7 %), wide linear range
(from 10 to 1000 nmol cm-3, r2 = 0.9999), high accuracy (recovery 93.3-109.4
%), and the precision of the results (RSD below 4.14 % in case of
repeatability and below 4.57 % in the case of intermediate precision). The
limit of detection and the limit of quantification are in the range
0.004-1.258 ?g cm-3 and 0.011-5.272 ?g cm-3, respectively. The results
demonstrate that the procedure can be used as a method for the determination
of the composition of primary amino acids of feed proteins.
Silage made from the whole-plant maize is one of the most popular forages in Serbia. Consumption of maize silage by cows can be up to 30-35 kg/day. In Serbia in the few last years in the focus of the ...public and agriculture community were two mycotoxins, aflatoxin B1 and its metabolite aflatoxin M1 due to the outbreak of contaminated maize which affected the Balkans in 2012. Maize is regularly checked on the occurrence of aflatoxin B1, however forages are often neglected as a potential source of mycotoxins in the nutrition of dairy cattle.
In this work, 48 samples of maize silage were analyzed for the occurrence of aflatoxin B1, ochratoxin A and zearalenone. Samples were collected from three regions (Bačka, Banat and Srem) in Vojvodina. In all samples, at least one mycotoxin above the limit of quantification was measured. Aflatoxin B1 was detected in 36 (75%) samples. In two samples from Banat, the concentration of aflatoxin B1 exceeded the maximum level (ML) set by Serbian regulation (30 µg/kg at moisture content of 12%). In seven samples, the concentration of aflatoxin B1 was above 20 µg/kg which is the EU regulated ML. Average concentration of ochratoxin A was 10.4 µg/kg, while the maximum measured value was 34.3 µg/kg. Maximum zearalenone content in all samples was 538 µg/kg while the average zearalenone concentration was 138 µg/kg.
The results from this research point out that mycotoxin contaminated silage in the region of Vojvodina, Serbia can significantly contribute to daily intake of aflatoxin B1 in dairy cattle.
Summary Wheat grain is commonly used for animal feeding in some regions while it is rarely used in others. Its nutrient composition is quite similar to more commonly used corn grain, but there are ...some concerns regarding its effect on animal performance and health. However, it appears that usage of wheat grain in animal feeding is dominantly affected by economic rather than nutritional reasons. When used with caution, wheat can be a good alternative to corn. In order to test this, 20 Wurttemberg lambs, three months old, were randomly separated in two groups and fed diets containing 600 g of corn grain, or 300 g of corn grain and 300 g of wheat grain, for a period of one month. The used grains were whole, non processed grains. Two diets contained the same commercial protein supplement and alfalfa hay was offered ad libitum. Both groups accepted their experimental diet well and readily consumed the amounts offered. No health problems were observed. Growth rate was higher in male than in female lambs, but was not affected by wheat inclusion.
Aflatoxin М1 was in the spotlight of public attention in Serbia and in the region in 2013 due to high level of this mycotoxin found in milk and milk products. Maximum allowed concentration of ...aflatoxin M1 in milk by EU regulation is 50 ng/kg, while in the Republic of Serbia, allowed concentration by the current regulation is 250 ng/kg. During seven months period, from May to November, samples of raw milk were being taken from six farms, with 60 to 330 cows, from the region of Autonomous Province of Vojvodina, the Republic of Serbia, for the purpose of monitoring the occurrence of aflatoxin M1 in milk and its variation during this period. The highest level of 39.8 ng/kg was found in November, while the mean value for the whole period was 7.9 ng/kg. None of the samples had higher level of this mycotoxin than allowed by EU regulation or by current legislation of the Republic of Serbia. The second group of samples included a total of 38 samples of raw milk, from the period of October and November, were taken from different producers from the region of Vojvodina and analyzed on the occurrence of aflatoxin M1. In this group of samples, the occurrence of aflatoxin M1 was much higher, with the average value of 230 ng/kg. The highest found value was 864 ng/kg. In 13 samples, the aflatoxin M1 content was higher than the allowed by the legislation of the Republic of Serbia, while in 24 (63.2 %) samples determined concentration exceeded the value allowed by EU regulation. Data from this work suggest huge differences in the occurrence of aflatoxin M1 in milk between the producers in this region. Regular monitoring is necessary to avoid situation with the elevated level of aflatoxin M1 in milk. This measure will protect both the consumers and the producers of milk and milk product.
The aim of this study was to investigate whether FTIR spectroscopy is an
accurate and valid technique for the assessment of quality parameters in raw
cow's milk: fat, protein, lactose, and total ...solids. The assessment was based
on calibration series and comparison with reference material. Furthermore, it
takes into account the results obtained in the inter-laboratory comparisons
(proficiency testing). The calibration samples were purchased from the
accredited regional reference laboratories. The validation parameters
included linearity, accuracy, repeatability, reproducibility, and robustness.
The linearity ratio was 0.95%. The biases calculated for the fat, protein,
lactose and dry matter were -0.33, 0.31, -0.25, and 0.06 respectively. The F
value from the F-test was used to determine the significant differences
between two independent sets of the results. The obtained results were as
follows: 1.469 for fat, 1.634 for protein, 1.192 for lactose, and 0.528 for
dry matter. The intra-laboratory reproducibility calculated as the Horwitz
Ratios for all parameters were within the criterion limits (0.5 to 0.8). The
data obtained for carry-over were 0.27% for fat, 0.52% for protein, 0.47% for
lactose, and 0.47% for dry matter. Based on the obtained results it can be
concluded that the FTIR spectroscopy is a reliable instrumental technique for
the determination of fat, protein, lactose and total solids in raw cow's
milk.
nema
A total of 226 samples of maize and 59 of wheat from the 2004-2007 harvests were investigated for the presence and concentration of deoxynivalenol (DON). Samples of the 2004 harvest were analyzed ...after their storing for one year in barns, while those of the 2005-2007 harvest were taken directly off fields immediately after the harvest. The samples were analyzed by liquid chromatography on an ODS Hypersil column with DAD detector and ELISA methods. The average incidence rate of DON in maize from the 2004 harvest was 50% (concentration range 0.042-2.460 mg/kg, average value 0.536 mg/kg), while for those of the 2005-2007 harvest it was 32.4% (concentration range 0.027-2.210 mg/kg, average value 0.223 mg/kg). In the case of wheat incidence rate of DON for 2004 harvest was 50.0% (concentration range 0.630-1.840 mg/kg, average value 1.235 mg/kg), while for those of the 2005-2007 harvest it was 34.5% (concentration range 0.057-0.423 mg/kg, average value 0.190 mg/kg). Concentrations in two samples of maize and one of wheat (one sample of each cereal being of the 2004 harvest) were above the maximum level adopted by the European Commission. The results obtained were analyzed as a function of climatic conditions and compared with those of the neighboring countries where the relevant data existed.
Corn is one of main crops in Serbia’s northern province of Vojvodina, and one of most important export products of Serbia. While majority of corn is used for grain production, lesser part is ...harvested for whole crop silage and used predominantly for cattle feeding. Irrigation is not widespread practice (”dry farming”) and corn silage yield and quality are under strong influence of season specific factors. Data on nutritional quality of corn silage samples from two seasons were obtained from Laboratory for quality control of feed and animal products of Department of Animal Science in Novi Sad, and used for comparison. Total of 80 samples were used. Corn silage samples from two seasons differed significantly in majority of analyzed parameters (crude fiber, crude fat, NDF, ADF and ADL) and observed differences can be attributed to different grain yield in two seasons. Corn silage samples from season with higher grain yield had significantly more fat, significantly less fiber (crude, NDF, ADF, ADL) and almost significantly (p=0,05) less crude protein. Differences in levels of dry matter and crude ash were not observed.
The aim of this work was to investigate aflatoxin (AF) occurrence in maize silage samples from 2017 harvest. In total, 30 samples of maize silage (whole plant) for nutrition of milking cows were ...inspected for AF occurrence. The samples originated from three regions (Bačka, Banat and Srem) in autonomous province (AP) of Vojvodina, Republic of Serbia (10 samples collected from each region). In AP Vojvodina, overall AF presence was 67% with its levels ranged from 3.52 to 24.64 µg/kg. Levels were standardized to 12% moisture content in all samples. Regarding each region, the highest presence was observed in Srem (80%) followed by Banat (70%), while the lowest presence was found in Bačka region (50%). However, the average AF contamination levels were not correlated to its presence. The highest AF level of 12.76 µg/kg (ranged from 6.16 to 24.64 µg/kg) was found in Srem region, whereas its lowest level was observed in Banat region (average of 4.40 µg/kg, ranged from 3.52 to 5.28 µg/kg). In the region of Bačka the average AF level was 8.45 µg/kg. Despite high presence, none of the samples contained AF above maximum level set by Serbian regulation (30 µg/kg), while 2 samples from Srem region exceeded the EU maximum level of 20 µg/kg. These results may be a result of warm and dry weather conditions during summer months of 2017, that prevailed on almost entire territory of AP Vojvodina.
Nutrition of dairy cattle is based on two components, concentrates and forages. The main forages in Vojvodina, north province of Serbia is silage made from the whole plant of corn. After the outbreak ...of aflatoxin B1 in corn in 2012, the occurrence of aflatoxin B1 in corn as a source of contamination of aflatoxin M1 in milk was very broadly investigated. There is no data regarding the occurrence of aflatoxin B1 in silage and how much silage can contribute to the overall intake of aflatoxin B1 in this region. This work is an attempt to estimate how much silage, in condition and practice used in Vojvodina, contributes to the intake of aflatoxin B1, and consequently aflatoxin M1 in milk. In total, 82 samples of corn grain and 72 samples of corn silage were analyzed on the occurrence of aflatoxin B1 during 2017-2018 period. Aflatoxin B1 was found in 13.41% of corn samples in the range from 6.82 to 187.5 ppb (average 63.5 ppb). All positive samples were from 2017, while no positive samples were found during 2018. Incidence of aflatoxin B1 in silage was 54.17% in the range of 3.5-58.0 ppb (12% moisture content) or 0.95-16.1 ppb in the fresh matter. Results suggest that silage can be a significant factor to overall intake of aflatoxin B1 and that further research is needed.
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