Antimicrobial use (AMU) in Switzerland is above target and requires reduction especially in dairy cattle. Measuring AMU is pivotal to identify starting points for AMU reduction and so are studies ...investigating its potential drivers in dairy farms worldwide. However, although AMU in dairy farms is high, studies estimating AMU specifically in tie stall farms are scarce. Tie stalls are a common housing system and their prevalence among dairy farms accounts to approximatively 73%, 41% and 40% in Canada, the US and Switzerland, respectively. The objectives of this cross-sectional, retrospective observational study were to estimate AMU using the newly established Swiss national reporting system for AMU in livestock and to identify associated factors on Swiss tie stall dairy farms. We calculated the treatment incidence (TI) by using the European Medicines Agency's methodology and their Defined Daily and Defined Course Dose (DDD/DCD) standards. Data on factors potentially associated with AMU were obtained through personal interviews with farm managers on 221 farms. Retrospectively, during a 1-year period, data on a total of 7,619 treatments were extracted from the national database. Associations between management factors and TI were analyzed using a generalized linear model with gamma distribution. The mean overall TI was 5.46 DDD/cow-year (±standard deviation: 4.10 DDD/cow-year). Intramammary treatment during lactation accounted for highest TI (3.24; ± 3.16 DDD/cow-year), whereas dry-cow therapy accounted for lowest TI (0.44; ± 0.49 DCD/cow-year). Five of the investigated management factors were significantly associated with TI. Organic production (estimate −2.16; 95% confidence interval 95 CI −3.62, −0.70) and herd size (estimate −0.81; 95 CI −1.23, −0.39) were negatively associated with TI. Specific cow breeds (Brown Swiss and Holstein Friesian: estimate 1.56; 95 CI 0.45, 2.68; estimate 1.42; 95 CI 0.03, 2.82, respectively; reference: other breeds) and the use of hygienic powders on the lying area (estimate 1.10; 95 CI 0.04, 2.17) were positively associated with TI. In conclusion, the Swiss national reporting system is a valuable tool for AMU estimation. Several herd characteristics and management factors were associated with AMU in tie stall farms. Further studies focusing on factors associated with AMU and which are amenable to intervention will help improve stewardship programs and subsequently reduce AMU in dairy cows.
Our aim was to simultaneously investigate the gut bacteria typical characteristic and conduct rumen metabolites profiling of high production dairy cows when compared to low‐production dairy cows. The ...bacterial differences in rumen fluid and feces were identified by 16S rDNA gene sequencing. The metabolite differences were identified by metabolomics profiling with liquid chromatography mass spectrometry (LC‐MS). The results indicated that the high‐production dairy cows presented a lower rumen bacterial richness and species evenness when compared to low‐production dairy cows. At the phylum level, the high‐production cows increased the abundance of Proteobacteria and decreased the abundance of Bacteroidetes, SR1, Verrucomicrobia, Euryarchaeota, Planctomycetes, Synergistetes, and Chloroflexi significantly (p < 0.05). At the genus level, the rumen fluid of the high‐production group was significantly enriched for Butyrivibrio, Lachnospira, and Dialister (p < 0.05). Meanwhile, rumen fluid of high‐production group was depleted for Prevotella, Succiniclasticum, Ruminococcu, Coprococcus,YRC22, CF231, 02d06, Anaeroplasma, Selenomonas, and Ruminobacter significantly (p < 0.05). A total of 92 discriminant metabolites were identified between high‐production cows and low‐production cows. Compared to rumen fluid of low‐production dairy cows, 10 differential metabolites were found up‐regulated in rumen fluid of high‐production dairy cows, including 6alpha‐Fluoropregn‐4‐ene‐3,20‐dione, 3‐Octaprenyl‐4‐hydroxybenzoate, disopyramide, compound III(S), 1,2‐Dimyristyl‐sn‐glycerol, 7,10,13,16‐Docosatetraenoic acid, ferrous lactate, 6‐Deoxyerythronolide B, vitamin D2, L‐Olivosyl‐oleandolide. The remaining differential metabolites were found down‐regulated obviously in high‐production cows. Metabolic pathway analyses indicated that most increased abundances of rumen fluid metabolites of high‐yield cows were related to metabolic pathways involving biosynthesis of unsaturated fatty acids, steroid biosynthesis, ubiquinone and other terpenoid‐quinone biosynthesis. Most down‐regulated metabolic pathways were relevant to nucleotide metabolism, energy metabolism, lipid metabolism and biosynthesis of some antibiotics.
Our aim was to simultaneously investigated the gut bacteria typical characteristic and conduct rumen metabolites profiling of high‐production dairy cows when compared to low‐production dairy cows. The aim of the study was to explore the typical gut bacteria and rumen typical metabolites matter of high‐production airy cows. After that, the results can be applied in the low‐yield dairy cows to improve their milking performance.
Dairy cows pass through a period of negative energy balance as they transition from late gestation to early lactation. Poor adaptation through this period, expressed as excessively elevated ...concentrations of non-esterified fatty acids (NEFAs) pre- or post-partum and elevated concentrations of β-hydroxybutyrate post-partum, increases an individual animal’s risk of post-partum disease, removal from the herd, reproductive difficulty, and reduced milk production. Field studies have shown that subclinical ketosis often affects 40% of cows in a herd although the incidence can be as high as 80%. Peak incidence occurs at 5days in milk, and cows that develop subclinical ketosis in the first week of lactation have a higher risk of negative effects and reduced milk production than cows that develop subclinical ketosis in the second week of lactation.
Herds with more than a 15–20% prevalence of excessively elevated concentrations of NEFAs and β-hydroxybutyrate in early lactation have higher rates of negative subsequent events, poorer reproduction, and lower milk yield than herds with a lower prevalence of negative energy balance. This paper reviews (1) strategies for testing of energy-related metabolites, (2) consequences of poor adaptation to negative energy balance (for individual animals and for herds), (3) treatment approaches for affected cows, and (4) economic considerations for testing and treating cows with poor adaptation to negative energy balance.
Management, nutrition, production, and genetics are the main reasons for the decline in fertility in the modern dairy cow. Selection for the single trait of milk production with little consideration ...for traits associated with reproduction in the modern dairy cow has produced an antagonistic relationship between milk yield and reproductive performance. The outcome is a multi-factorial syndrome of subfertility during lactation; thus, to achieve a better understanding and derive a solution, it is necessary to integrate a range of disciplines, including genetics, nutrition, immunology, molecular biology, endocrinology, metabolic and reproductive physiology, and animal welfare. The common theme underlying the process is a link between nutritional and metabolic inputs that support complex interactions between the gonadotropic and somatotropic axes. Multiple hormonal and metabolic signals from the liver, pancreas, muscle, and adipose tissues act on brain centers regulating feed intake, energy balance, and metabolism. Among these signals, glucose, fatty acids, insulin-like growth factor-I, insulin, growth hormone, ghrelin, leptin, and perhaps myostatin appear to play key roles. Many of these factors are affected by changes in the somatotropic axis that are a consequence of, or are needed to support, high milk production. Ovarian tissues also respond directly to metabolic inputs, with consequences for folliculogenesis, steroidogenesis, and the development of the oocyte and embryo. Little doubt exists that appropriate nutritional management before and after calving is essential for successful reproduction. Changes in body composition are related to the processes that lead to ovulation, estrus, and conception. However, better indicators of body composition and measures of critical metabolites are required to form precise nutritional management guidelines to optimize reproductive outcomes. The eventual solution to the reduction in fertility will be a new strategic direction for genetic selection that includes fertility-related traits. However, this will take time to be effective, so, in the short term, we need to gain a greater understanding of the interactions between nutrition and fertility to better manage the issue. A greater understanding of the phenomenon will also provide markers for more targeted genetic selection. This review highlights many fruitful directions for research, aimed at the development of strategies for nutritional management of reproduction in the high-producing subfertile dairy cow.
Six rumen-fistulated dairy cows were used in 2 trials to validate the technique for the collection of ruminal fluid by an oral stomach tube (OST). Trial 1 was conducted to compare the differences of ...ruminal fermentation parameters among rumen sites (cranial dorsal, cranial ventral, central, ventral, caudal dorsal, and caudal ventral). The ruminal fluid was collected once per day for 3 consecutive days through rumen cannula (RC). The samples were analyzed for pH, volatile fatty acids (VFA), ammonia N, sodium, potassium, calcium, chloride, and phosphorus concentrations. The ruminal fermentation parameters varied significantly among rumen sites. Compared with the central or ventral rumen, the cranial dorsal rumen had significantly higher pH, ammonia, and sodium concentrations and lower acetate, propionate, and butyrate concentrations, indicating that the sampling site may be one of the main factors contributing to the difference in ruminal fermentation parameters between the samples collected via the OST and RC. In trial 2, the fermentation parameters of ruminal fluid collected via OST at 2 insertion depths (180 or 200cm) were compared with those of ruminal fluid collected via RC (ventral sac). Ruminal fluid was collected once per week at 5 to 6h after morning feeding. When the OST was inserted to a depth of 180cm, the OST head was located in the cranial dorsal (atrium) of the rumen. The ruminal fluid collected via the OST had higher pH and sodium concentrations but lower VFA, potassium, calcium, and phosphorus concentrations than that collected via RC. However, when the OST was inserted to a depth of 200cm, the OST head could pass through the front rumen pillar and reach the central rumen for sampling. No differences were found in pH, VFA, ammonia N, and ion concentrations between the samples collected via the 2 sampling methods. These results indicated that the OST should be inserted to reach the central rumen to obtain representative rumen fluid samples.
Mammary synthesis of milk fat continues to be an active research area, with significant advances in the regulation of lipid synthesis by bioactive fatty acids (FAs). The biohydrogenation theory ...established that diet-induced milk fat depression (MFD) in the dairy cow is caused by an inhibition of mammary synthesis of milk fat by specific FAs produced during ruminal biohydrogenation. The first such FA shown to affect milk fat synthesis was trans-10, cis-12 conjugated linoleic acid, and its effects have been well characterized, including dose-response relationships. During MFD, lipogenic capacity and transcription of key mammary lipogenic genes are coordinately down-regulated. Results provide strong evidence for sterol response element-binding protein-1 (SREBP1) and Spot 14 as biohydrogenation intermediate responsive lipogenic signaling pathway for ruminants and rodents. The study of MFD and its regulation by specific rumen-derived bioactive FAs represents a successful example of nutrigenomics in present-day animal nutrition research and offers several potential applications in animal agriculture.
The effects of environmental heat-stress on production and reproduction in dairy cows have been intensively studied throughout the past few decades. In light of climate changes and global warming, ...this issue has gained attention worldwide. So far, most of the documentations are related to warmer-climate regions, however, environmental thermal stress has recently been reported in cooler regions, such as Europe.
The review attempts to present the experiences from the past years and lessons for the present. The review highlights some of the environmental characterizations and provides some practical approaches to estimate the level of heat load on farms. For instance, the intensity of heat stress can be evaluated by the temperature humidity index (THI). Other environmental parameters, such as the increased number of consecutive hot days or the increased frequency of extremely hot days, can be also used to estimate the level of heat load on farms.
Exposure of dairy cows to environmental thermal stress results in multiple behavioral changes, physiological responses and endocrinological alterations, which in sequence, lead to reduced reproductive performance. Multiple in-vitro studies have been performed for better understanding the mechanism by which heat stress impairs reproductive processes. However, the current review focuses mainly on animal reactions and on the limitations of physiological and behavioral responses in maintaining normothermia, without human intervention. The review provides evidence that thermal stress induces alterations in the hypothalamus–pituitary–ovarian axis. For instance, impaired gonadotropin secretion, attenuation of follicular development, reduced steroid production and progesterone concentration in the plasma. These were found to be associated with impaired estrus behavior, reduced oocyte developmental competence and embryo survival. Heat stress also has direct and indirect effects on the preimplantation embryo. The review summarizes the thermo-sensitivity of the embryo and the acquisition of its thermotolerance through early developmental stages. Understanding the effects of environmentally elevated temperature on the reproductive physiology of lactating cows is extremely important for the development of new strategies in order to mitigate the effects of heat stress on farms.
The review also provides various types of management and practical tools, in order to alleviate the effects of thermal stress. It introduces some approaches that have been developed during recent years, ones that have been practically used to alleviate the effect of the environmental heat load and suggested to be implanted. Cooling is the predominant strategy used nowadays in order to alleviate the effects of heat stress. It includes indirect cooling of the environment surrounding the animal, by providing shed and ventilation (with or without water) or direct evaporative cooling of the cow with water and fans. Using an efficient cooling system can improve milk production during the hot season, but it cannot eliminate the decline in reproduction. The review also discusses some additional approaches such as timed artificial insemination, hormonal treatment and embryo transfer, which have already been developed. These are suggested to be examined, adapted and implemented in dairy farms located in new regions that have recently suffered from environmental heat stress. The review also discusses unclear points and open questions some of which might lead new research directions.
•The review attempts to present the experiences from the past and its lessonsfor the present.•Climate changes and global warming have gained attention worldwide, including in cooler regions.•The intensity of heat load can be evaluated on farms.•Environmental thermal stress leads to behavioral changes, physiologicalresponses and endocrinological alterations.•Nowadays, cooling is the predominant strategy to any additional approaches.
The transition from pregnancy to lactation is critical in dairy cows. Among others, dairy cows experience a metabolic stress due to a large change in glucose and lipid metabolism. Recent studies ...revealed that bile acids (BA), besides being involved in both the emulsification and solubilization of fats during intestinal absorption, can also affect the metabolism of glucose and lipids, both directly or indirectly by affecting the gut microbiota. Thus, we used untargeted and targeted metabolomics and 16S rRNA sequencing approaches to investigate the concentration of plasma metabolites and BA, the composition of the rectum microbial community, and assess their interaction in transition dairy cows. In Experiment 1, we investigated BA and other blood parameters and gut microbiota in dairy cows without clinical diseases during the transition period, which can be seen as well adapted to the challenge of changed glucose and lipid metabolism. As expected, we detected an increased plasma concentration of β-hydroxybutyrate (BHBA) and nonesterified fatty acids (NEFA) but decreased concentration of glucose, cholesterol, and triglycerides (TG). Untargeted metabolomic analysis of the plasma revealed primary BA biosynthesis was one of the affected pathways, and was consistent with the increased concentration of BA in the plasma. A correlation approach revealed a complex association between BA and microbiota with the host plasma concentration of glucose and lipid metabolites. Among BA, chenodeoxycholic acid derivates such as glycolithocholic acid, taurolithocholic acid, lithocholic acid, taurochenodeoxycholic acid, and taurodeoxycholic acid were the main hub nodes connecting microbe and blood metabolites (such as glucose, TG, and NEFA). In Experiment 2, we investigated early postpartum dairy cows with or without hyperketonemia (HPK). As expected, HPK cows had increased concentration of NEFA and decreased concentrations of glucose and triglycerides. The untargeted metabolomic analysis of the plasma revealed that primary BA biosynthesis was also one of the affected pathways. Even though the BA concentration was similar among the 2 groups, the profiles of taurine conjugated BA changed significantly. A correlation analysis also revealed an association between BA and microbiota with the concentration in plasma of glucose and lipid metabolites (such as BHBA). Among BA, cholic acid and its derivates such as taurocholic acid, tauro α-muricholic acid, and taurodeoxycholic acid were the main hub nodes connecting microbe and blood metabolites. Our results indicated an association between BA, intestinal microbe, and glucose and lipid metabolism in transition dairy cows. These findings provide new insight into the adaptation mechanisms of dairy cows during the transition period.
Body-condition dynamics are known to affect the different steps of reproduction in cattle (cyclicity, estrus expression, fertilization, embryo development). This has led to a widespread idea that ...there is an ideal-target optimal body condition, but no clear profile has yet been identified. Here we investigated the relationships between body condition score (BCS) profiles and reproductive performance in dairy cows. Data were from Holstein or Normande herds in 6 French experimental farms. In the Holstein breed, we discriminated 4 BCS profiles based on combining BCS at calving (Low: around 2.6 points, or High: around 3.3 points) with BCS loss after calving (Moderate (M): ≤ 1.0 points, or Severe (S): > 1.0 points). The Low-M profile mostly included multiparous cows with higher milk yield and lower reproductive performance than cows in the 3 other profiles. Low-M cows that experienced abnormal ovarian activity had lower reproductive performance than their profile-mates. Moreover, 67% of Low-M cows kept the same profile at the following lactation. The High-S profile mostly included primiparous cows with lower milk yield and higher reproductive performance than cows in other profiles. In High-S cows, higher milk yields correlated to higher risk of failure to calf on first insemination. Moreover, 38% of High-S cows kept the same profile at the following lactation, and none changed to Low-M. The other 2 BCS profiles (Low-S and High-M) were intermediate in terms of milk yield and reproductive performance. In Normande, we discriminated 3 BCS profiles based on combining BCS at calving (Low: around 2.6 points, or High: around 3.5 points) with BCS loss after calving (Flat (F): flat with no loss, Moderate (M): around 0.5 points, or Severe (S): around 1.0 point). The Low-M and High-S profiles included cows with similar performance, even though High-S-profile cows showed better but not significantly different milk yield and reproduction performance. The High-F profile included cows that were more likely to experience abnormal ovarian activity and fail at first insemination than cows in other profiles. More than 50% of Normande cows with 2 successive lactations kept in the same BCS profile at the next lactation. Even though a low BCS at calving combined with severe BCS loss (more than 1 point) after calving was found to increase reproductive failure, there was no evidence of an optimal BCS profile for reproduction in dairy cows, and reproductive success or failure is multifactorial.
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