The hepatogenic role of mycotoxins is well-known, but their action on some biochemical and haematological parameters in the dairy cows is yet to be completely clarified. The investigation monitored ...the modification of blood test values and of some biochemical parameters from the serum and urine of dairy cows reared in small family farms and which consumed feeds contaminated with mycotoxins. Ten blood samples and 10 urine samples were collected and subsequently analysed. The samples were collected from 5 family farms, one in each of the following countied: Dolj, Giurgiu. Ilfov, Călăraşi and Galaţi. The blood and urine samples were analysed for their biochemical parameters. The results of the biochemical analyses of the blood and urine samples were correlated with the results of the mycotoxicological analysis of 105 samples of forages collected from the surveyed family dairy farms. The results showed that some biochemical parameters exceeded the normal physiological level, which may be the result of a defence reaction of the organism to the aggressive action of the mycotoxins identified in the forages given to the dairy cows.
The aim of the paper was to evaluate the influence that season has on the water consumption behaviour in lactating dairy cows. Researches were carried out on twenty multiparous Romanian Black and ...White cows, during summer and winter seasons. Cows were housed in a tied stanchion barn 24 h, and had free access to a water source. Environmental parameters, quantity of consumed forages and milk yield were measured each day of the experiments. Studied traits were: number of drinking bouts and duration of the drinking periods, frequency of the drinking periods, time length between consumption of the forages and first drinking period and time length between milking and first drinking period. Average number of drinking bouts on 24 h registered during winter season was 8.15, and 16.10 during summer season. Differences registered between the two seasons for this trait were significantly statistic (p<0.001). Duration of a drinking period was of 0.82 minutes in the winter and of 0.84 minutes during summer season.
In Denmark, agriculture is the largest source of anthropogenic methane emissions (81%), mainly from cattle (dairy and beef) farms. Whole-farm methane emissions were quantified at nine Danish cattle ...farms, using the tracer gas dispersion method. Five to six measurement campaigns were carried out at each farm, covering a full year. Of the nine cattle farms, seven were home to dairy cows and two to beef cattle. The farms represented typical breeds, housing and management systems used in Denmark. Whole-farm methane emission rates ranged from 0.7 to 28 kg h−1, with the highest measurements seen at locations with the highest number of animals. Emissions tended to be higher from August to October, due to elevated temperatures and high amounts of stored manure during this period of the year. The average emission factor (EF) for dairy cow farms was 26 ± 8.5 g Livestock Unit (LU)−1 h−1, whereas it was 16 ± 4.1 LU−1 h−1 for beef cattle farms, i.e. 38% lower for the latter. The use of deep litter house management explained some of the differences found in the EFs for dairy cows. Methane emission rates estimated using IPCC models and national guidelines tended, on average for all farms and measurements, to be underestimated by 35% in comparison with the measured methane emissions, for all models and farms. The results suggest that future improvements to inventory models should focus on enteric methane emissions from beef cattle and manure methane emissions for both dairy cows and beef cattle, especially from deep litter management.
•Whole-farm methane emissions were quantified using the tracer dispersion method.•Methane emissions from 0.7 to 28 kg h−1 were quantified at nine cattle farms.•Methane emissions tended to be higher during late summer/autumn.•Emission factors averaged 26 g LU−1 h−1 for dairy cow 16 g LU−1h−1 for beef cattle.•Inventory estimations were on average 35% lower than farm-scale measured emissions.
The aim of the study was to determine how the values of ambient temperature affect the welfare of the animals with regard to the average performance. The study was carried out in the agricultural ...company Petrovice during the summer and winter seasons. The experiment included Holstein dairy cattle. Air temperature was measured using a data logger with sensors (Datalogger COMET 3120) in the stable. Data on average yield were taken from farm records and then processed using Microsoft Excel. The air temperature is very variable and its changes animals react immediately. Measured values of air temperature in the stable are important for optimal welfare. It affects the productivity of dairy cows, milk quality, reproduction and animal health.
The aim of this paper was to assess the effects of environmental temperature on the main reproduction indices in Romanian Spotted dairy cows. The study was carried out on 144 Romanian Spotted ...multiparous cows kept in loose housing throughout the whole year at S.C.D.C.B. Arad. The following traits were analyzed: the voluntary waiting period (from calving to first A.I.), the number of artificial inseminations (A.I.) for a new gestation and interval between calving and new pregnancy, according to the season. Thus, in the winter season, characterized by cold temperatures, but relatively easy incurred by dairy cows, the voluntary waiting period was 51.74 days, and 71.35 days to the new gestation, requiring a number of 1.97 AIs per pregnancy. In spring season, characterized by temperatures near the thermal comfort for cattle, the voluntary waiting period was 56.78 days, 96.71 days until the new gestation, with 2.02 AIs per pregnancy. In summer season, characterized by high temperatures, above the thermal comfort, time to first service was 68.34 days, requiring 100.76 days for the installation of new gestation and using 2.85 AIs per pregnancy. Autumn, season with temperatures well supported by dairy cows, favoured shorter periods to first service 56.84 days. Therefore, only 63.16 days were required for installation of a new gestation, and 2.44 AIs per pregnancy.
This experiment studied the effect of 3 different physical forms of linseed fatty acids (FA) on cow dairy performance, milk FA secretion and composition, and their relationship with methane output. ...Eight multiparous, lactating Holstein cows were assigned to 1 of 4 dietary treatments in a replicated 4 x 4 Latin square design: a control diet (C) based on corn silage (59%) and concentrate (35%), and the same diet supplemented with whole crude linseed (CLS), extruded linseed (ELS), or linseed oil (LSO) at the same FA level (5% of dietary dry matter). Each experimental period lasted 4 wk. Dry matter intake was not modified with CLS but was lowered with both ELS and LSO (-3.1 and -5.1 kg/d, respectively) compared with C. Milk yield and milk fat content were similar for LSO and ELS but lower than for C and CLS (19.9 vs. 22.3 kg/d and 33.8 vs. 43.2 g/kg, on average, respectively). Compared with diet C, CLS changed the concentrations of a small number of FA; the main effects were decreases in 8:0 to 16:0 and increases in 18:0 and cis-9 18:1. Compared with diet C (and CLS in most cases), LSO appreciably changed the concentrations of almost all the FA measured; the main effects were decreases in FA from 4:0 to 16:0 and increases in 18:0, trans-11 16:1, all cis and trans 18:1 (except trans-11 18:1), and nonconjugated trans 18:2 isomers. The effect of ELS was either intermediate between those of CLS and LSO or similar to LSO with a few significant exceptions: increases in 17:0 iso; 18:3n-3; trans-11 18:1; cis-9, trans-11 conjugated linoleic acid; and trans-11, trans-13 conjugated linoleic acid and a smaller increase in cis-9 18:1. The most positive correlations (r = 0.87 to 0.91) between milk FA concentrations and methane output were observed for saturated FA from 6:0 to 16:0 and for 10:1, and the most negative correlations (r = -0.86 to -0.90) were observed for trans-16+cis-14 18:1; cis-9, trans-13 18:2; trans-11 16:1; and trans-12 18:1. Thus, milk FA profile can be considered a potential indicator of in vivo methane output in ruminants.
Considerable progress has been made in understanding the protein and amino acid (AA) nutrition of dairy cows. The chemistry of feed crude protein (CP) appears to be well understood, as is the ...mechanism of ruminal protein degradation by rumen bacteria and protozoa. It has been shown that ammonia released from AA degradation in the rumen is used for bacterial protein formation and that urea can be a useful N supplement when lower protein diets are fed. It is now well documented that adequate rumen ammonia levels must be maintained for maximal synthesis of microbial protein and that a deficiency of rumen-degradable protein can decrease microbial protein synthesis, fiber digestibility, and feed intake. Rumen-synthesized microbial protein accounts for most of the CP flowing to the small intestine and is considered a high-quality protein for dairy cows because of apparent high digestibility and good AA composition. Much attention has been given to evaluating different methods to quantify ruminal protein degradation and escape and for measuring ruminal outflows of microbial protein and rumen-undegraded feed protein. The methods and accompanying results are used to determine the nutritional value of protein supplements and to develop nutritional models and evaluate their predictive ability. Lysine, methionine, and histidine have been identified most often as the most-limiting amino acids, with rumen-protected forms of lysine and methionine available for ration supplementation. Guidelines for protein feeding have evolved from simple feeding standards for dietary CP to more complex nutrition models that are designed to predict supplies and requirements for rumen ammonia and peptides and intestinally absorbable AA. The industry awaits more robust and mechanistic models for predicting supplies and requirements of rumen-available N and absorbed AA. Such models will be useful in allowing for feeding lower protein diets and increased efficiency of microbial protein synthesis.
The present descriptive study was designed to identify the type of foot lesions found in lame dairy cows and to describe the distribution of foot lesions between front and hind limbs and lateral and ...medial claws. A total of 379 lactating Holstein Friesian cows were included in this study. All cows were scored for locomotion using a scale from1 (normal) to 5 (severely lame) based on gait and posture. Lame cows were defined as having locomotion score (LS) of 34 or 5. Each lame cow was properly restrained in trimming chute and each foot was examined for any lesion using Dutch 5 steps method. Lesions were identified in 231 cows. Infection type lesions were diagnosed in 52 cows (22.5%) and non-infection type lesions were diagnosed in 179 cows (77.5%). A total of 377 lesions were identified and the number of lesions recorded per cow ranged from 1 to 2 (median 1.6). Sole haemorrhage (SH), white line disease (WLD) and digital dermatitis (DD) made the majority of lesions. A higher mean number of DD, interdigital necrobacillosis (IN), WLD, and toe ulcer (TU) per cow was found in the ≥ 3 lactation cows compared with 1st or 2nd lactation cows. Increasing parity was associated with a increasing trend in mean number of infections diagnosed per cow. A higher proportion of cows was diagnosed with lesions on the hind limbs compared with front limbs (198 vs 33 cows). Fifty three lesions were found on the front limbs and 324 lezins were on the hind limbs. The hind lateral and medial claws were affected by 234 and 50 lesions respectively (72.2% vs 15.4%). Inspection of foot lesions as a routine management practice facilitates earlier identification and treatment of lesions enhancing herd productivity and welfare.
Heat stress (HS) in dairy cows causes considerable losses in the dairy industry worldwide due to reduced animal performance, increased cases of metabolic disorders, altered rumen microbiome, and ...other health problems. Cows subjected to HS showed decreased ruminal pH and acetate concentration and an increased concentration of ruminal lactate. Heat-stressed cows have an increased abundance of lactate-producing bacteria such as
and unclassified Enterobacteriaceae, and soluble carbohydrate utilizers such as
,
, and unclassified Bacteroidaceae. Cellulolytic bacteria, especially Fibrobacteres, increase during HS due to a high heat resistance. Actinobacteria and
, both acetate-producing bacteria, decreased under HS conditions. Rumen fermentation functions, blood parameters, and metabolites are also affected by the physiological responses of the animal during HS. Isoleucine, methionine, myo-inositol, lactate, tryptophan, tyrosine, 1,5-anhydro-D-sorbitol, 3-phenylpropionic acid, urea, and valine decreased under these conditions. These responses affect feed consumption and production efficiency in milk yield, growth rate, and reproduction. At the cellular level, activation of heat shock transcription factor (HSF) (located throughout the nucleus and the cytoplasm) and increased expression of heat shock proteins (HSPs) are the usual responses to cope with homeostasis. HSP70 is the most abundant HSP family responsible for the environmental stress response, while HSF1 is essential for increasing cell temperature. The expression of bovine lymphocyte antigen and histocompatibility complex class II (DRB3) is downregulated during HS, while HSP90 beta I and HSP70 1A are upregulated. HS increases the expression of the cytosolic arginine sensor for mTORC1 subunits 1 and 2, phosphorylation of mammalian target of rapamycin and decreases the phosphorylation of Janus kinase-2 (a signal transducer and activator of transcription factor-5). These changes in physiology, metabolism, and microbiomes in heat-stressed dairy cows require urgent alleviation strategies. Establishing control measures to combat HS can be facilitated by elucidating mechanisms, including proper HS assessment, access to cooling facilities, special feeding and care, efficient water systems, and supplementation with vitamins, minerals, plant extracts, and probiotics. Understanding the relationship between HS and the rumen microbiome could contribute to the development of manipulation strategies to alleviate the influence of HS. This review comprehensively elaborates on the impact of HS in dairy cows and introduces different alleviation strategies to minimize HS.
Although in dairy cows the mammary gland (MG) is the major net user of essential AA (EAA) supply, milk protein synthesis from absorbed EAA is not a straightforward process. Early studies identified 2 ...groups of EAA based on different pattern of mammary utilization: group 1 Met, Phe (+Tyr), Trp, where MG uptake was similar to secretion in milk protein, and group 2 (Arg, Ile, Leu, Lys, Thr, and Val), where uptake exceeded milk protein output. This review examines the validity of this classification under variable protein supply through a meta-analysis, with the outcomes then explained with studies in which the fates of individual EAA were monitored using isotope approaches. For the meta-analysis, the Fick principle, based on stoichiometric transfer of Phe+Tyr uptake to milk protein, was used to estimate mammary plasma flow across all studies. This approach was judged acceptable because doubling Phe supply did not result in mammary oxidation of Phe+Tyr and either limited or no contribution of peptides to Phe and Tyr mammary supply could be detected. The AA content of proteins synthesized by the MG was estimated from milk protein composition, and the uptake-to-output ratio (U:O) for individual AA was re-calculated based on these assumptions. Analysis of individual samples by isotopic dilution resulted in reduced variance compared with analysis on pooled samples performed with an AA analyzer. Globally, the U:O of His and Met is maintained close to unity under variable protein supply. The group 2 AA could be subdivided. First, the U:O for group "2v" AA (Ile, Leu, Val, and Lys) is greater than 1 and varied with protein supply. Accordingly, the increased U:O of Leu, induced by duodenal casein infusion, led to extra-mammary Leu oxidation. Decreasing Lys supply decreased Lys U:O and the associated transfer of N to non-EAA, mainly to Glx, Asx, Ser, and Ala. Second, the U:O of group "2nv" AA, Arg and Thr, does not vary with protein supply. The Arg U:O averages 2.5, whereas the Thr U:O, albeit averaging 1.2, does not differ from unity. Excess of both these AA is probably directed toward the synthesis of non-EAA rather than energy supply. Overall, the ability of the MG to use excess EAA-N supply offers alternative sources of N and C for energy provision, lactose synthesis and non-EAA synthesis. The latter function spares dietary non-EAA for other necessary processes, such as gluconeogenesis and energy supply, in other tissues to support lactation.
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