Dairy Cows In Relation Research Articles

Serum macroelements and microelements levels in periparturient dairy cows in relation to fatty liver diseases

BackgroundFatty liver in dairy cows is a common metabolic disease defined by triglyceride (TG) buildup in the hepatocyte. Clinical diagnosis of fatty liver is usually done by liver biopsy, causing considerable economic losses in the dairy industry owing to the lack of more effective diagnostic methods. Therefore, this study aimed to investigate the potential utility of blood biomarkers for the diagnosis and early warning of fatty liver in dairy cows.ResultsA total of twenty-four lactating cows within 28 days after parturition were randomly selected as experimental animals and divided into healthy cows (liver biopsy tested, n = 12) and cows with fatty liver (liver biopsy tested, n = 12). Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the macroelements and microelements in the serum of two groups of cows. Compared to healthy cows (C), concentrations of calcium (Ca), potassium (K), magnesium (Mg), strontium (Sr), selenium (Se), manganese (Mn), boron (B) and molybdenum (Mo) were lower and copper (Cu) was higher in fatty liver cows (F). Meanwhile, the observed differences in macroelements and microelements were related to delivery time, with the greatest major disparity between C and F occurring 7 days after delivery. Multivariable analysis was used to test the correlation between nine serum macroelements, microelements and fatty liver. Based on variable importance projection and receiver operating characteristic (ROC) curve analysis, minerals Ca, Se, K, B and Mo were screened as the best diagnostic indicators of fatty liver in postpartum cows.ConclusionsOur data suggested that serum levels of Ca, K, Mg, Se, B, Mo, Mn, and Sr were lower in F than in C. The most suitable period for an early-warning identification of fatty liver in cows was 7 days after delivery, and Ca, Se, K, B and Mo were the best diagnostic indicators of fatty liver in postpartum cows.

Diagnosis of clinical cervicitis and vaginitis in dairy cows in relation to various postpartum uterine disorders

There is poor agreement between clinical findings and results of diagnostic tests in postpartum uterine diseases that may be explained at least in part by the presence of inflammation and infection at sites other than the endometrium. It was hypothesized that clinical cervicitis and vaginitis are components of reproductive tract inflammatory disorders in postpartum dairy cows. A total of 61 postpartum dairy cows were enrolled in a nested case-control design. Periparturient disease occurrence in weeks 1 (1w), 3 (3w), and 5 (5w) postpartum were recorded. Clinical cervicitis was diagnosed in 36.0, 40.1, and 31.1% of cows in 1w, 3w, and 5w postpartum, respectively. Approximately 64% of cows with clinical endometritis in 5w postpartum also had clinical cervicitis (p ≤ 0.05). Prevalence of clinical and cytological vaginitis was 0% in 5w postpartum. Average days open: 110 for healthy cows and 117 for cows with clinical cervicitis (p ≤ 0.001), 145 for cows with clinical cervicitis and clinical endometritis (p < 0.005), and 199 for cows with clinical cervicitis and cytological endometritis (p < 0.001). Contrary to vaginitis, high prevalence of clinical cervicitis and its association with clinical endometritis and longer average days open suggested a substantial role of the condition in postpartum uterine diseases.

Behavioural changes to moderate heat load in grazing dairy cows under on-farm conditions

Heat stress poses an increasing risk to welfare, health and productivity of dairy cows, especially for cows on pasture. To apply timely mitigation strategies for grazing cows, simple indicators are needed that signal heat stress. We conducted an exploratory study on the behaviour of grazing dairy cows in relation to the environmental heat load on four commercial dairy farms in Switzerland with herd sizes ranging from 20 to 57 cows. In a scan-sampling procedure standing/lying, feeding/ruminating, low inter-individual distances, proximity to drinker, use of natural shade and insect infestation were observed during 30 days (5–9 days/per farm). Additionally, 10 focal cows per farm were equipped with accelerometers to analyse lying duration and locomotor activity during on average 46 days per farm. On one farm all cows (N = 57) were equipped with GPS devices which were used to calculate inter-individual distances among cows continuously during 69 days. Air temperature and relative humidity were recorded to calculate the temperature-humidity index (THI). For behaviours recorded in direct observations, a principal component analysis was performed for variable reduction. The first three principal components (PC) as well as the variables from automatic measurements were used as outcome variables in mixed effects models with daily maximum THI (THImax), time of day (continuous, in 10 min intervals) and their interaction as explanatory variables. The three PCs could be described as: “feeding and standing”, “proximity to drinker” and “standing in close proximity and seeking shade”. The daily pattern of these PC's differed by THImax (interaction time of day * THImax; all p < 0.01). On days with high THImax compared to days with lower THImax cows were seen more often close to the drinker in the morning, but not in the afternoon when they were observed standing close to each other and in the shade. On days with high THImax, cows also were lying less and increased their locomotor activity towards noon (interaction time of day * THImax; p < 0.001). Data from GPS devices confirmed the findings: On days with high THImax, cows reduced their inter-individual distances over the course of the day, while this was not observed on days with lower THImax (interaction time of day * THImax; p < 0.001). Insect infestation increased with higher THImax. We conclude that a distinct change in daily behavioural patterns, especially a reduction of lying behaviour, an increase in locomotor activity and a decrease in inter-individual distances could be used to monitor heat stress of dairy cows on pasture.

The Value of Current Ante Mortem Meat Inspection and Food Chain Information of Dairy Cows in Relation to Post Mortem Findings and the Protection of Public Health: A Case for a More Risk-Based Meat Inspection.

In this study, the contribution of the ante mortem (AM) inspection and the food chain information (FCI) to ensuring meat safety and public health was investigated, by evaluating the slaughterhouse findings of 223,600 slaughtered dairy cows in the Netherlands. The outcome of this study was that the ante mortem (AM) and post mortem (PM) inspections have a substantial overlap, and that with regard to food safety and public health in over 99% of cases the PM could even be omitted on the basis of the AM. In this study, the data provided by the dairy farmers on the current FCI forms contributed little to nothing with regard to the outcomes of AM and PM inspection. It is concluded that current meat inspection procedures need an update and a more risk-based approach needs to be adopted. Regarding this, the AM inspection of dairy cattle should remain, because it plays an important role in ensuring food safety (e.g., by preventing contamination of the slaughter line by excessively dirty animals, or animals with abscesses), monitoring animal welfare and in detecting some important notifiable diseases. The PM inspection, however, could in many cases be omitted, provided there is a strict AM inspection complemented by a vastly improved (automated) way of obtaining reliable FCI.

Influence of Using Various Levels of Protein Concentrate in Rations of Ayrshire Dairy Cows on Rumen Microbiome, Reproductive Traits and Economic Efficiency.

Simple SummaryNumerous studies in animal nutrition science have demonstrated a close connection between the chemical composition and nutritional value of cow diets, the number of rumen bacterial communities and animal productive and reproductive performance. Thus, the microorganisms of cow rumen play a primary role in the processes of digestion; meanwhile, it is necessary to highlight that their functional significance is much wider. The aim of this study was to investigate the outcomes of the inclusion of different levels of protein concentrate in rations of Ayrshire dairy cows in relation to the rumen microbiome, reproductive traits and economic value. Our manuscript presents molecular biological studies to establish the quantitative and specific composition of the microorganisms of the rumen. T-RFLP analysis was performed to determine the percentage of the components of the bacterial community. The results showed that the supplementation of “Agro-Matic” caused no deviations from the normal standards of cellulolytic, amylolytic, transit and pathogenic bacteria, no impact on reproductive traits and significantly improved the profitability of the milk production process. These findings provide a scientific addition for a greater understanding of the rumen microbiome of dairy cows when supplemented by different levels of protein concentrate in their rations.Animal feeding research has revealed a close relationship between the chemical composition and nutritional value of cow rations, the number of rumen bacterial communities and animal productivity. Our present research aimed to investigate the outcome of inclusion of different levels of protein concentrate in rations of Ayrshire dairy cows in relation to the rumen microbiome, reproductive traits and economic value. Forty-five Ayrshire cows were divided into three groups (15 in each). The first control group 0 AM was fed the basal ration, while the second 1 AM and third 2 AM groups were fed the basic ration with the sunflower cake replaced by different levels of protein concentrate Agro-Matic (1 and 1.5 kg/head/day, respectively). Ruminal fluid samples, reproductive parameters and economic value were studied. During the early lactation period, 120 days in milk (DIM), the number of pathogenic microorganisms decreased in both the 1 AM and 2 AM groups when compared with the control group 0 AM; moreover, a significant decrease in Peptococcus bacteria was recorded in the 1 AM group, while Fusobacterium decreased in the 2 AM group. At the end of lactation, the total number of cellulolytic bacteria increased with the use of protein concentrate in animals of the 1 AM group when compared with the control group. Regarding undesirable bacteria, the 2 AM group recorded the highest value for Lactobacilli and Actinobacteria when compared with the 0 AM group (0.18 and 8.90 vs. 0.04 and 4.24), and the differences were significant (p < 0.05). The insemination index and the duration of the days open period decreased in the 2 AM group, while the differences were p > 0.05. The profitability of milk production increased by 2.76% and 6.28% in both supplemented groups, and the differences compared to the 0 AM group were significant. We conclude that the supplementation of Agro-Matic caused no deviations from the normal standards of cellulolytic, amylolytic, transit and pathogenic bacteria, no impact on reproductive functions and significantly improved the profitability of the milk production process of Ayrshire dairy cows.

젖소 사육환경과 영양조성에 대한 마케팅 정보가 치즈 선호도에 미치는 영향

The taste preference for cheese is primarily dependent on an individual’s habitual experience, such as personal memories since childhood. Cheese is not a traditional food in Korea, and therefore, the liking of cheese is acquired mainly through the exposure to European natural cheese by frequent travels rather than habitual experience. Although Korean dairy farms started the production of European style natural cheese because of surplus milk undulation, yet its demand has been consistently increasing in the last decade. Most of the mountain cheese variety in Europe are produced during the summer season on mountain pastures, especially in countries surrounded by the Alps. Nevertheless, not only consumers but also mountain cheese producers cannot comprehensively explain the differences in the nutritional properties of the milk from cows that grazed on mountain pasture and cows that were raised indoors. As the demand for cheese consumption is steadily increasing in Korea, it is necessary to study the effects of providing marketing information regarding the health conditions and rearing system of dairy cows in relation to the nutritional composition of cheese. In addition to the marketing focus on health-promoting unsaturated fatty acid composition of milk and cheese, the relationship between providing the marketing information on the raising environments of cows and the overall liking of mountain cheese were also investigated.

Thyroid blood profile in high-yielding dairy cows with different ovarian reactions to superovulatory treatment

The reaction of cow ovaries to superovulatory treatment significantly depends on the physiological state of the animal, primarily on its endocrine status. The available information indicates that thyroid hormones can affect the processes of ovarian folliculogenesis in cattle.Objective: To study the thyroid profile in the blood of high-yielding dairy cows in relation to the response of the ovaries to superovulatory treatment.Materials and methods. Thirty four cycles of superovulation stimulation in 16 Holstein cows were studied. After synchronization of the estrous cycle and superovulatory treatment, on the first day of insemination (Day 0), the number of follicles with a diameter of more than 5 mm was recorded in each ovary using an ultrasound scanner. Furthermore, on Day 0 and on the 7th day after insemination (Day 7), the blood was taken from the cows to analyze the content of sex steroids and thyroid hormones by ELISA. The ovarian reaction was assessed by the total number of detected follicles and was divided into 3 types: I – more than 12 follicles (strong), II – 8-12 follicles (moderate), III – less than 8 follicles (weak).Results. The content of sex steroid hormones in the blood of cows on Day 0 did not depend on the type of the ovarian response. By Day 7, the concentration of progesterone increased in most animals, but was 2.7-fold higher (P &lt;0.01) in the case of the strong reaction (type I) than in the case of the weak reaction (type III). Conversely, the serum concentration of estradiol-17β decreased 1.1 times (P &lt;0.05) in cows with the moderate ovarian response (type II). In animals with the type I reaction, the content of thyroxine (T4) in the blood declined 1.2 times (P &lt;0.05) one week after insemination. During the study period, there was also a reduction in the concentration of total triiodothyronine (T3) and reverse T3 (rT3) in cows with ovarian responses of types I and II (1.1-1.3 times, P &lt;0.01-0.05). Concurrently, on Day 0, the T3 content in the blood of individuals with the type II reaction was 1.2-fold higher (P &lt;0.05) than in individuals with the type III reaction. Totally, a positive relationship was found between the concentration of estradiol-17β and the concentration of thyroid hormones: for T4 – in the case of the type II ovarian response (r = 0.44, P &lt;0.05), for T3 – in the case of the type I and II responses ( r = 0.57-0.64, P &lt;0.001-0.05), for rT3 – in the case of the type III response (r = 0.52, P &lt;0.01).Conclusions. Thus, the content of triiodothyronine in the blood of high-yielding dairy cows on the day of insemination is associated with the ovarian response to superovulatory treatment. In addition, during one week after insemination, the state of the thyroid system and its relationship with the level of estradiol-17β in the blood differ with different reactions of the ovaries to the introduction of exogenous gonadotropic hormones.

Serum and Hair Trace Element and Mineral Levels in Dairy Cows in Relation to Daily Milk Yield.

The objective of the present study was to assess hair and serum trace element and mineral levels in dairy cows in relation to daily milk yield. A total of 70 healthy 5-6-year-old Simmental cows were divided into two groups (n = 35) with high and low daily milk yield using median as a cut-off value. Hair and serum trace element and mineral content was evaluated using inductively coupled plasma mass-spectrometry. A nearly twofold difference in daily milk yield (43.8 ± 9.7 vs 21.3 ± 7.1 L/day, p < 0.001) was significantly associated with 11% lower hair Cu (p = 0.043) and 35% higher Se levels (p = 0.058) content when compared animals with lower daily milk yield. Serum trace element levels were found to be more tightly associated with milk productivity in dairy cows. Particularly, serum levels of Se and Zn were found to be 73 and 35% higher in cows with higher milk productivity in comparison to animals with lower milk production, respectively. Serum Co levels also tended to increase with higher milk productivity. Serum minerals including Ca, Mg, and P were also found to be higher in highly productive cows by 6%, 14%, and 71%, respectively. The overall regression model based on serum trace element and mineral levels accounted for 38% of daily milk production variability. Generally, improvement of essential trace element and mineral supply, as well as prevention of copper overload in dairy cows, may be considered the potential tool for modulation of milk productivity.

The Effect of Feeding Management and Culling of Cows on the Lactation Curves and Milk Production of Primiparous Dairy Cows.

The study attempted to estimate the lactation curves of primiparous dairy cows in relation to their feeding management. Therefore, the first aim of the study was to determine and compare the lactation curves of primiparous dairy cows using Wood's model and to estimate the association between the lactation curves and feeding management. The second objective was to investigate the effect of the culling rate on improvement in the milk yield of primiparous dairy herds. The study was conducted on four commercial dairy farms of Polish Holstein-Friesian cows using different feeding systems (TMR-total mixed ration and PMR-partial mixed ration) and management (T1-one TMR throughout lactation; P1-one PMR throughout lactation; T2 and T3-three feed periods such as FRESH, TMR I and TMR II according to days in milk). The data used for the study were obtained from monthly milk performance evaluations of 1662 primiparous cows conducted by the Polish Federation of Cattle Breeding and Dairy Farmers throughout the year 2015. Wood's lactation model was used to plot curves for milk yield, fat and protein content, lactose content, and milk urea contents. The highest milk yield for the whole lactation and in the peak lactation phase was recorded for cows in herd T1. This herd reached peak lactation on day 105 of milking, with an average milk yield of 42.1 kg, which was about 5 kg more milk than in the other herds. The study showed that the culling of primiparous cows in herd T1 after 30, 60 and 90 days of lactation prevented a significant reduction in milk yield in a 305-day lactation. It also increased average milk production by 1586.9 kg per primiparous dairy cow.

An Empirical Analysis on the Longevity of Dairy Cows in Relation to Economic Herd Performance.

Several studies have stated the various effects of an increased dairy cow longevity on economic herd performance, but empirical studies are lacking. This study aimed to investigate the association between longevity of dairy cows and the economic performance of dairy herds based on longitudinal Dutch accounting data. Herd and farm accounting data (n = 855 herds) over the years 2007–2016 were analyzed. Herd data contained yearly averages on longevity features, herd size and several production variables. Longevity was defined as the age of cows at culling and by lifetime milk production of culled cows. Farm accounting data contained yearly averages on revenues, fixed and variable costs of the herds, by which gross margins were defined. Data was analyzed using generalized linear mixed modeling, with gross margin as dependent variable. The independent variables consisted of average age of culled cows, average lifetime production of culled cows, year, herd size, herd intensity (milk production per ha), herd expansion rate, soil type, milking system, successor availability, total full-time equivalent, heifer ratio (% of heifers per cow) and use of outsourced heifer rearing. Herd was included as a random effect to account for the heterogeneity among herds. Descriptive statistics showed that the average age of culled cows was 5.87 (STD = 0.78) years and the average lifetime milk production of culled cows was 31.87 (STD = 7.56) tons per cow with an average herd size of 89 cows (STD = 38.85). The average age of culled cows was stable over the 10 years (variation between 5.79 AND 5.90 years). The gross margin was on average €24.80/100 kg milk (STD = 4.67), with the lowest value in year 2009 and the highest value in year 2013. Gross margin was not significantly associated with age of culled cows and lifetime milk production of culled cows. Variance in longevity between herds was large (STD = 0.78 years) but herds with a higher longevity did not perform economically better nor worse than herds resulting in lower longevity. This indicates that, within current practice, there is potential for improving longevity in order to meet society's concerns on animal welfare and environmental pollution, without affecting the economic performance of the herd.

Developing of a model to predict lying behavior of dairy cows on silvopastoral system during the winter season

Lying behavior is an important indicator of the cows' welfare and health. In this study, we evaluate the effect of the physical environment on dairy cows' behaviors raised on a silvopastoral system through a predictive model. There was a difference (p<0.01) in soil surface temperature (SST) and black globe-humidity index (BGHI) between the shaded and sunny areas of the silvopastoral system. The BGHI was the variable most important to classify the cows' decision to seek shaded or sunny areas, while the soil surface temperature affected the choice for the area to perform the lying behaviors. In order to understand the influence of these parameters on cows' lying behavior, we developed another predictive model relating the SST and BGHI with cows lying at shaded and sunny areas. There was significance (p<0.01) for all model parameters. The odds of cows lying increased by approximately 2% with each degree of SST. In contrast, the probability of the cows lying in the shaded areas was 35% less than in sunny areas. The model developed in this study was efficient in identifying changes in the behavior of dairy cows in relation to physical environment. The BGHI influenced the areas used by cows to performing their standing behavior, while the areas used for lying behavior were influenced by the SST.

Reproductive Performance of Dairy Cows in Relation to Genotype, Age, Parity, Body Weight and Body Condition Score at Rajshahi District of Bangladesh

The present study was carried out from selected areas at Rajshahi district to evaluate the reproductive performance of dairy cows in relation to breed/genotype, age, parity, body weight and body condition. A total of 500 cows selected and data were collected directly from the dairy farms owner by using pre-tested questionnaires during the period from September 2013 to December 2014. The average reproductive performance (RP) were recorded as age at puberty (AP) 26.42±0.22 m, age at first calving (AFC) 35.48±0.22 m, post-partum heat period (PPHP) 121.85±3.48 days, service per conception (S/C) 1.93±0.04, days open (DO) 136.80±3.57 days and calving interval (CI) 401.04±3.94 days. Genotype had significant effect (P&lt;0.05) on all the reproductive traits except on S/C. Local (L) × Holstein Friesian (HF) genotype showed earlier AP and AFC than L× Sahiwal (SL) and L. Age group had significant (P&lt;0.05) effect on AP, AFC and other parameters were not significant (P&gt;0.05). Middle age groups of cows had shown better RP than others groups. Parities of cows had significant effect (P&lt;0.05) on PPHP, S/C, DO except on AP, AFC and CI. Third parity had better RP than others. The best RP was found in &gt;300 kg BW groups. Body condition score had significant effect (P&lt;0.05) on all RP. Good body condition score (BCS) had excellent RP.&#x0D; Res. Agric., Livest. Fish.7(3): 481-495, December 2020

Hormonal Profile Study of Bangladeshi Crossbred Dairy Cows in Relation to Repeat Breeding

The repeat breeding condition affects both the fertility of cows and the economy of farmers and the nation. Normal levels of various biochemical constituents are indispensable for the normal functioning of various body systems of animals, including the reproductive system. The hormonal profile is an indicator of the reproductive status and aids in the prognosis and restoration of animal fertility. The present study explores the implication of four hormones (luteinizing hormone, follicle-stimulating hormone, human chorionic gonadotropin and prolactin) on the normal cycle breeding process of Bangladeshi normal cyclic cows and repeat breeder dairy cows. Among four hormones, the levels of luteinizing hormone and prolactin were significantly different between the normal cyclic cows and repeat breeder cows. The assessment of hormonal profile aids in ameliorating the repeat breeding conditions of the dairy cows. The findings of the present study could be applied in overcoming repeat breeding problems in dairy cows and thus, economic loss could be lessened.

Hormonal Profile Study of Bangladeshi Crossbred Dairy Cows in Relation to Repeat Breeding

The repeat breeding condition affects both the fertility of cows and the economy of farmers and the nation. Normal levels of various biochemical constituents are indispensable for the normal functioning of various body systems of animals, including the reproductive system. The hormonal profile is an indicator of the reproductive status and aids in the prognosis and restoration of animal fertility. The present study explores the implication of four hormones (luteinizing hormone, follicle-stimulating hormone, human chorionic gonadotropin and prolactin) on the normal cycle breeding process of Bangladeshi normal cyclic cows and repeat breeder dairy cows. Among four hormones, the levels of luteinizing hormone and prolactin were significantly different between the normal cyclic cows and repeat breeder cows. The assessment of hormonal profile aids in ameliorating the repeat breeding conditions of the dairy cows. The findings of the present study could be applied in overcoming repeat breeding problems in dairy cows and thus, economic loss could be lessened.

Metabolomics of Milk Reflects a Negative Energy Balance in Cows.

Dairy cows can experience a negative energy balance (NEB) in early lactation when feed intake is too low to meet the energy requirements for body maintenance and milk production. Metabolic changes occur in mammary gland cells of animals experiencing a negative energy balance. We studied these metabolic changes in milk samples from dairy cows in relation to energy balance status using liquid chromatography–mass spectrometry (QQQ-LC–MS) and nuclear magnetic resonance (1H NMR). NMR and LC–MS techniques are complementary techniques that enabled a comprehensive overview of milk metabolites in our study. Energy balance and milk samples were obtained from 87 dairy cows. A total of 55 milk metabolites were reliably detected, of which 15 metabolites were positively correlated to energy balance and 20 were negatively correlated to energy balance. Cows in NEB produced more milk with increased milk fat yield and higher concentrations of citrate, cis-aconitate, creatinine, glycine, phosphocreatine, galactose-1-phosphate, glucose-1-phosphate, UDP-N-acetyl-galactosamine, UDP-N-acetyl-glucosamine, and phosphocholine but lower concentrations of choline, ethanolamine, fucose, N-acetyl-neuraminic acid, N-acetyl-glucosamine, and N-acetyl-galactosamine. During NEB, we observed an increased leakage of cellular content, increased synthesis of nucleic acids and cell membrane phospholipids, an increase in one-carbon metabolic processes, and an increase in lipid-triglyceride anabolism. Overall, both apoptosis combined with cellular renewal is paramount in the mammary gland in cows in NEB.

Study on the hormonal profile in crossbred dairy cows in relation to repeat breeding at Baghabari milk shed areas, Bangladesh

Repeat breeding (RP) is a one of the most significant problem in dairy cattle because it increased production cost of insemination, treatment, feed, labor and management and also increased calving interval with decreased milk production. This study was conducted at the different Bathan areas of Shahjadpur Upazila under Sirajgonj district. The total of 30 repeat breeder cows was selected randomly to determine their reproductive hormonal profile before and after synchronization at the selected areas and repeat breeder cows were marked by ear tag and collected breeding history of each individual cow. All experimental RP were synchronized by the administration of GnRH (day- 0), PGF2α (day-7) and Artificial Insemination (AI) with GnRH (day-9). Blood samples were collected before and after synchronization during standing heat period of estrous cycle of each cow. The total experiment was done and analyzed in the laboratory by using endocrine detection kits (Mono LelacR USA). This present study revealed that the level of luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone (P4) were significantly differed between repeat breeder cows and synchronized repeat breeder cows. These findings clearly indicated that reproductive hormonal aberrations might be one of the major causes of repeat breeding in Baghabari milk shed areas.&#x0D; Asian Australas. J. Biosci. Biotechnol. 2018, 3 (3), 237-240

Histological characteristics of ovarian follicle atresia in dairy cows with different milk production.

Follicle atresia in mammals is a universal phenomenon characteristic by degenerative morphological changes in granulosa and theca cells. The unfavourable effect of milk production in relation to fertility has been studied starting from the 70s of the last century; however, there is no unambiguous and persuasive data on association of ovarian atresia with milk yield of dairy cows. The aim of this study was to define histological signs of ovarian follicle atresia in dairy cows in relation to their milk production. The ovaries were recovered from slaughtered Holstein dairy cows assigned into two groups according to average level of annual milk production: Group 1 (n=25)-low (≤8,000kg/year) and Group 2 (n=23)-high (≥8,000kg/year). Atresia of antral follicles was evaluated on the basis of histopathological image (staining with basic fuchsine and toluidine blue) of nonovulated follicles, classified into five categories: an initial atresia, cystic atresia, obliterated atresia, atresia with luteinization of the granulosa and follicle structures of the fibrous body-corpus fibrosum. We found that the histopathological image of follicle atresia in groups of low-milk- or high-milk-producing cows is essentially similar. Prevalent form of atresia in follicles of all experimental cows was the formation of fibrous bodies and obliterated atresia. The occurrence of fibrous bodies was significantly higher (55.44%) in low-milk-producing cows compared with high-milk-producing cows (34.61%). In the same way, the higher incidence of obliterated atresia was recorded in ovarian follicles from cows with the lower milk production (36.96%) compared to the cows with the higher milk production (25.48%). In contrast, ovaries from lower milk-producing cows showed lower (p<0.05) incidence of initial (p<0.001) and cystic (p<0.05) follicle atresia than ovaries from the higher milk-producing cows. Our results show that cows in the higher lactation group showed more initial and cystic atresia, what may adversely affect the fertility of dairy cows.

Comparison of microalgae and rapeseed meal as supplementary protein in the grass silage based nutrition of dairy cows

Two experiments were conducted to evaluate microalgae as a protein supplement in the nutrition of lactating dairy cows in relation to unsupplemented and rapeseed meal supplemented diets. In both experiments multiparous Finnish Ayrshire cows were fed separately fixed amount of cereal-sugar beet pulp based concentrate (11kg/d in Exp. 1 and 12kg/d in Exp. 2), and grass silage ad libitum. In Exp. 1, six cows (212days in milk; DIM) were used in a replicated 3×3 Latin square. Diets were supplemented isonitrogenously with rapeseed meal (pelleted rapeseed supplement, RSS), mixture of Spirulina platensis and Chlorella vulgaris microalgae (1:1 on dry matter (DM) basis; ALG) or a mixture of RSS and ALG (1:1 on crude protein (CP) basis; RSS-ALG). In Exp. 2, four intact cows and four rumen cannulated cows (190 DIM) were used in a replicated 4×4 Latin square. Treatments consisted of basal diet without protein supplement (NEG) or supplemented similarly as in Exp. 1 with the exception of RSS-ALG and ALG containing only S. platensis. Protein supplementation increased fibre and N digestibility but did not affect dry matter intake (DMI) or milk yield. The substitution of rapeseed by microalgae did not affect total DMI or milk yield in neither of the experiments, but changed the quality of DMI in Exp.2 by linearly decreasing concentrate:forage ratio of the diet due to poorer palatability of microalgae. The efficiency of N utilisation (NUE) in milk production varied from moderate (Exp. 1) to high (Exp. 2), and in Exp. 2 was decreased by both protein supplementation and microalgae inclusion in the diet. Protein supplementation or microalgae inclusion in the diet did not affect ruminal pH or major volatile fatty acids in Exp. 2, but both increased ruminal NH3-N concentration. There was likely a shortage of N for rumen microbes on NEG in Exp. 2 as indicated by low milk urea N and increased microbial N flow on protein supplemented diets. In both experiments, only minor differences were observed in plasma metabolites when microalgae substituted rapeseed. Even though arterial histidine concentrations were high, arterial histidine and carnosine concentrations (Exp. 1 and 2) and milk protein yields (Exp. 2) decreased by microalgae inclusion suggesting that histidine supply may become suboptimal on microalgae supplemented diets. Experiments demonstrated the suitability of microalgae as protein supplement for dairy cows, however, the protein value of microalgae is likely slightly lower than that of rapeseed meal.

Thyroid Hormones, Insulin, Body Fat, and Blood Biochemistry Indices in Dairy Cows During the Reproduction/Production Cycle

AbstractThis study investigated the changes in: thyroid hormones, amount of subcutaneous fat, and selected indices of blood biochemistry in dairy cows in relation to the reproduction/production cycle. The blood samples were collected bothante- andpost-partumevery two weeks. When evaluating the mean values of the investigated indices, the major changes were recorded in dairy cows 3 to 14 days after calving. During this period, we observed a significant decrease in the mean serum levels of T3(P &lt; 0.05), T4(P &lt; 0.01), and triglycerides (P &lt; 0.01). An opposite trend was observed with a significant increase after calving in the: mean serum levels of β-hydroxybutyrate (P &lt; 0.05), urea (P &lt; 0.01), and mean AST activities (P &lt; 0.05). A significant increase over the normal range was recorded in the average levels of non-esterified fatty acids (P &lt; 0.01) and total bilirubin (P &lt; 0.01). From the next sampling (28 days after calving) onwards we recorded a significant increase in the blood serum levels of cholesterol (P &lt; 0.01), total lipids (P &lt; 0.01), total protein (P &lt; 0.01), as well as a significant decrease in the insulin levels (P &lt; 0.05) and a reduced layer of subcutaneous fat (P &lt; 0.01). The blood serum iodine concentration showed only slight significant changes (P &lt; 0.05) during the observation. Blood serum levels of glucose did not show any significant changes during the whole observation period. Within the whole observation period we found a negative correlation between T3levels and the layer of subcutaneous fat (r = −0.2606; P &lt; 0.05). This correlation was much more marked in cows 3 to 14 days after calving (r = −0.5077; P &lt; 0.05), which may indicate a possible relationships between the thyroid status, body condition, andpost partumnegative energy balance.

Milk metabolome relates enteric methane emission to milk synthesis and energy metabolism pathways

Methane (CH4) emission of dairy cows contributes significantly to the carbon footprint of the dairy chain; therefore, a better understanding of CH4 formation is urgently needed. The present study explored the milk metabolome by gas chromatography-mass spectrometry (milk volatile metabolites) and nuclear magnetic resonance (milk nonvolatile metabolites) to better understand the biological pathways involved in CH4 emission in dairy cattle. Data were used from a randomized block design experiment with 32 multiparous Holstein-Friesian cows and 4 diets. All diets had a roughage:concentrate ratio of 80:20 (dry matter basis) and the roughage was grass silage (GS), corn silage (CS), or a mixture of both (67% GS, 33% CS; 33% GS, 67% CS). Methane emission was measured in climate respiration chambers and expressed as CH4 yield (per unit of dry matter intake) and CH4 intensity (per unit of fat- and protein-corrected milk; FPCM). No volatile or nonvolatile metabolite was positively related to CH4 yield, and acetone (measured as a volatile and as a nonvolatile metabolite) was negatively related to CH4 yield. The volatile metabolites 1-heptanol-decanol, 3-nonanone, ethanol, and tetrahydrofuran were positively related to CH4 intensity. None of the volatile metabolites was negatively related to CH4 intensity. The nonvolatile metabolites acetoacetate, creatinine, ethanol, formate, methylmalonate, and N-acetylsugar A were positively related to CH4 intensity, and uridine diphosphate (UDP)-hexose B and citrate were negatively related to CH4 intensity. Several volatile and nonvolatile metabolites that were correlated with CH4 intensity also were correlated with FPCM and not significantly related to CH4 intensity anymore when FPCM was included as covariate. This suggests that changes in these milk metabolites may be related to changes in milk yield or metabolic processes involved in milk synthesis. The UDP-hexose B was correlated with FPCM, whereas citrate was not. Both metabolites were still related to CH4 intensity when FPCM was included as covariate. The UDP-hexose B is an intermediate of lactose metabolism, and citrate is an important intermediate of Krebs cycle–related energy processes. Therefore, the negative correlation of UDP-hexose B and citrate with CH4 intensity may reflect a decrease in metabolic activity in the mammary gland. Our results suggest that an integrative approach including milk yield and composition, and dietary and animal traits will help to explain the biological metabolism of dairy cows in relation to methane CH4 emission.