Jana Frahm

Effects of prepartal body condition score and peripartal energy supply of dairy cows on postpartal lipolysis, energy balance and ketogenesis: an animal model to investigate subclinical ketosis.

Subclinical ketosis is a metabolic disorder which often goes undiagnosed and leads to constricted performance and an impairment of general condition. In the current study subclinical ketosis was characterised by a β-hydroxybutyrate (BHB) concentration of >1·2 mmol/l in blood serum. To generate this metabolic situation, an animal model was created. The model, based on group-specific interaction of dietary energy supply and body condition, is appropriate for testing the medical effectiveness of treating this kind of ketosis and its concomitants. During the trial, 18 dairy cows (primiparous and pluriparous) were assigned, according to their body condition score (BCS) 6 weeks before expected parturition, to a normal [6.78 MJ net energy for lactation (NEL)/kg dry matter; 20% concentrate] or to a high-energy feeding group (7·71 MJ NEL/kg dry matter; 60% concentrate). Therefore cows with the highest BCS were allocated to the high-energy group to enhance the contrast with the control group. Statistical analysis was done using the MIXED procedure of SAS. Effects were declared significant when P-values were ⩽0.05. Owing to the higher energy concentration and dry matter intake, the energy intake and balance was significantly higher in the high-energy feeding group, with strong effects on lipid metabolism and health in blood and liver post partum. Within the first 2 weeks after calving, 8 out of 9 cows (89%) of the high-energy group had BHB values indicative of subclinical ketosis. These cows also had significantly higher values of non-esterified fatty acids (NEFA), aspartate transaminase (AST) and glutamate dehydrogenase (GLDH) post partum, as well as a raised total lipid content of the liver. RQUICKI, a calculated parameter which is based on serum concentrations of glucose, insulin and NEFA to assess the insulin sensitivity, was not affected by treatment. Therefore, RQUICKI does not seem to be the right parameter for diagnosing decreased insulin sensitivity in cows affected by subclinical ketosis. The milk fat and the fat:protein ratio of the high-energy group was also higher, even though there was no decrease in milk yield for cows with subclinical BHB values.

Effects of an energy-dense diet and nicotinic acid supplementation on production and metabolic variables of primiparous or multiparous cows in periparturient period

It is well observed that feeding energy-dense diets in dairy cows during the dry period can cause metabolic imbalances after parturition. Especially dairy cows with high body condition score (BCS) and fed an energy-dense diet were prone to develop production diseases due to metabolic disturbances postpartum. An experiment was conducted to determine the effects of an energy-dense diet and nicotinic acid (NA) on production and metabolic variables of primiparous and multiparous cows in late pregnancy and early lactation which were not pre-selected for high BCS. Thirty-six multiparous and 20 primiparous German Holstein cows with equal body conditions were fed with energy-dense (60% concentrate/40% roughage mixture; HC group) or adequate (30% concentrate/70% roughage mixture; LC group) diets prepartum. After parturition, concentrate proportion was dropped to 30% for all HC and LC groups and was increased to 50% within 16 days for LC and within 24 days for HC cows. In addition, half of the cows per group received 24 g NA supplement per day and cow aimed to attenuate the lipid mobilisation postpartum. Feeding energy-dense diets to late-pregnant dairy cows elevated the dry matter (p < 0.001) and energy intake (p < 0.001) as well as the energy balance (p < 0.001) without affecting the BCS (p = 0.265) during this period. However, this did not result in any metabolic deviation postpartum as the effects of prepartum concentrate feeding were not carried over into postpartum period. Multiparous cows responded more profoundly to energy-dense feeding prepartum compared with primiparous cows, and parity-related differences in the transition from late pregnancy to lactation were obvious pre- and postpartum. The supplementation with 24 g NA did not reveal any effect on energy metabolism. This study clearly showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in multiparous and primiparous cows not selected for high BCS. A genetic predisposition for an anabolic metabolic status as indicated by high BCS may be crucial for developing production diseases at the onset of lactation.

Effects of oregano on performance and immunmodulating factors in weaned piglets

Many health effects can be attributed to the Mediterranean herb oregano (Origanum vulgare L.) and several studies demonstrated the improving effect on performance, changes in blood count, antibacterial, antifungal and immunmodulating abilities. The majority of these investigations were carried out with processed essential oil, while whole plant material was only used in a few studies. Thus, the aim of the present experiment was to test the effect of increasing proportions of dried oregano in piglet feed on health and performance, with a special focus on immune modulation. A total of 80 male castrated weaned piglets (body weight [BW] 7.9 kg ±1.0 kg) were used in a feeding experiment lasting 5 weeks. They were assigned to 4 experimental groups: a control diet, and three diets with an oregano supplementation at 2 g, 4 g and 8 g per kg feed, respectively, corresponding to 23.5 mg, 46.9 mg and 93.9 mg carvacrol/kg DM. After 3 weeks, half of each group was challenged with 5 µg lipopolysaccharides (LPS) per kg BW. Blood samples were collected 2 h after LPS stimulation and analysed for T-cell phenotypes, granulocyte activity, clinical-chemistry as well as white and red blood count. The results indicate no effects of oregano on performance. In contrast, oregano altered the lymphocyte proportion and the ratio of CD4+ and CD8+ T-cells as well as the triglyceride concentration in the serum of non-stimulated and in LPS-stimulated piglets. In conclusion, whole plant supplementation of oregano to piglet feed altered immune-related parameters, but did not modulate the acute inflammatory response induced by LPS stimulation.

Description of a bovine model for studying digestive and metabolic effects of a positive energy balance not biased by lactation or gravidity

Physiological consequences of adaptation to and continued feeding of a high-energetic diet were studied in eight non-pregnant, non-lactating dairy Holstein cows over a period of 16 weeks. The first six weeks served as an adaptation period from the low energetic straw-based diet (3.8 MJ NEL/kg DM) to the high-energetic ration (7.5 MJ NEL/kg DM). Intake of dry matter (DM) increased with dietary energy concentration from 9 to 20 kg/d up to week 9 to 12 and decreased thereafter. The initial live weight (LW) of 550 ± 60 kg was increased linearly and corresponded to an average daily LW gain of 2.3 ± 0.3 kg. Energy balance increased approximately nine-fold to a maximum of 114 MJ NEL/d in week 10. Ruminal fermentation pattern was completely changed from an acetate dominating profile to a propionate based one, which was paralleled by a marked increase in the rumen fluid endotoxin concentration. Unlike blood glucose concentration, which increased continuously, that of cholesterol and triglycerides started to increase after an initial stagnation. In conclusion, both ruminal adaptation to a high-energetic diet and the continued feeding of such a diet induced digestive and metabolic adaptations in non-pregnant, non-lactating cows characterised by a progressing positive energy balance.

Mitochondrial DNA copy number and biogenesis in different tissues of early- and late-lactating dairy cows

Energy balance in dairy cows changes during the course of lactation due to alterations in voluntary feed intake and energy required for milk synthesis. To adapt to the demands of lactation, energy metabolism needs to be regulated and coordinated in key organs such as adipose tissue (AT), liver, and mammary gland. Mitochondria are the main sites of energy production in mammalian cells and their number varies depending on age, organ, and physiological condition. The copy number of the mitochondrial genome, the mitochondrial DNA (mtDNA), reflects the abundance of mitochondria within a cell and is regulated by transcriptional and translational factors. Environmental, physiological, and energetic conditions change during lactation and we thus hypothesized that these changes may influence the mtDNA copy number and the abundance of genes regulating mitochondrial biogenesis. Therefore, we aimed to provide an overview of mitochondrial biogenesis in liver, subcutaneous (sc)AT, mammary gland, and peripheral blood cells during early and late lactation in dairy cows. German Holstein cows (n=21) were fed according to their requirements, and biopsies from scAT, liver, mammary gland, and blood were collected in early and late lactation and assayed for relative mtDNA copy numbers and the mRNA abundance of genes regulating mitochondrial biogenesis, such as nuclear-respiratory factor 1 and 2 (NRF-1, NRF-2), mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor-gamma coactivator 1-α (PGC-1α). The number of mtDNA copies increased from early to late lactation in all tissues, whereas that in peripheral blood cells was greater in early compared with late lactation. Moreover, mitochondrial activity enzymes (i.e., citrate synthase and cytochrome c oxidase) increased from early to late lactation in scAT. Comparing the number of mtDNA copies between tissues and blood in dairy cows, the highest mtDNA content was observed in liver. The mRNA abundance of genes related to mitochondrial biogenesis changed in a tissue-specific manner when comparing early versus late lactation. The mtDNA copy number was associated with transcriptional factors only in AT, suggesting nontranscriptional regulation of mtDNA in the other tissues. We detected strong correlations between peripheral blood mtDNA and tissue mtDNA content in early lactation. Peripheral blood forms an appropriate medium to display the cellular content of mtDNA copy numbers and consequently the cellular energy status of tissues during early lactation.

Does Dietary Deoxynivalenol Modulate the Acute Phase Reaction in Endotoxaemic Pigs?--Lessons from Clinical Signs, White Blood Cell Counts, and TNF-Alpha.

We studied the interaction between deoxynivalenol (DON)-feeding and a subsequent pre- and post-hepatic immune stimulus with the hypothesis that the liver differently mediates the acute phase reaction (APR) in pigs. Barrows (n = 44) were divided into a DON-(4.59 mg DON/kg feed) and a control-diet group, surgically equipped with permanent catheters pre- (V. portae hepatis) and post-hepatic (V. jugularis interna) and infused either with 0.9% NaCl or LPS (7.5 µg/kg BW). Thus, combination of diet (CON vs. DON) and infusion (CON vs. LPS, jugular vs. portal) created six groups: CON_CONjug.-CONpor., CON_CONjug.-LPSpor., CON_LPSjug.-CONpor., DON_CONjug.-CONpor., DON_CONjug.-LPSpor., DON_LPSjug.-CONpor.. Blood samples were taken at −30, 15, 30, 45, 60, 75, 90, 120, 150, 180 min relative to infusion and analyzed for leukocytes and TNF-alpha. Concurrently, clinical signs were scored and body temperature measured during the same period. LPS as such induced a dramatic rise in TNF-alpha (p < 0.001), hyperthermia (p < 0.01), and severe leukopenia (p < 0.001). In CON-fed pigs, an earlier return to physiological base levels was observed for the clinical complex, starting at 120 min post infusionem (p < 0.05) and persisting until 180 min. DON_LPSjug.-CONpor. resulted in a lower temperature rise (p = 0.08) compared to CON_LPSjug.-CONpor.. In conclusion, APR resulting from a post-hepatic immune stimulus was altered by chronic DON-feeding.

Effects of Prepartum Dietary Energy Level and Nicotinic Acid Supplementation on Immunological, Hematological and Biochemical Parameters of Periparturient Dairy Cows Differing in Parity.

Simple Summary Several biological changes occur during the transition from late pregnancy to early lactation which is associated with a high susceptibility of health disorders. Nicotinic acid, as feed additive, is suggested to balance catabolic metabolism of periparturient dairy cows by attenuating lipolysis and impact production performance. This study provides information of the biological changes occurring around parturition with special emphasis on differences between primiparous and multiparous cows. Present results showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in dairy cows which were similar in body condition score. Nicotinic acid supplementation did not reveal any effect. Abstract The periparturient period is critical according to health, productivity and profitability. As this period is fundamental for the success of the lactation period, the interest in improving periparturient health by dietary supplements increased in recent years. The present study investigated the effects of feeding nicotinic acid (NA) combined with varying dietary energy densities on immunological, hematological and biochemical parameters of periparturient cows differing in parity. Thirty-six multiparous and 20 primiparous dairy cows were enrolled in the study 42 days before expected parturition date until 100 days postpartum with the half of the cows being supplemented with 24 g of NA/d. After parturition a diet with 30% concentrate was fed to all cows which was followed by different concentrate escalation strategies. Dietary NA supplementation was ceased on day 24 postpartum. Dietary NA increased (P = 0.010) serum nicotinamide concentrations (mean of 3.35 ± 1.65 µg/mL), whereas NA could not be detected. Present data emphasize that periparturient cows are faced with major physiological challenges and that both parity-groups have different prerequisites to adapt to those changes irrespective of NA supplementation. The overfeeding of energy to cows which were similar in body condition score had only minor effects on periparturient immune system function and the metabolism of those cows.

The effects of a ration change from a total mixed ration to pasture on health and production of dairy cows

In pasture-based dairy production systems, dairy cows often receive a silage- and concentrate-based ration [total mixed ration (TMR)] during wintertime and are gradually introduced to fresh herbage in spring. The present study aimed to investigate how the transition to this new nutritional situation influenced different production and health indicators. A 10-wk trial was performed in spring 2014, including 60 dairy cows of the German Holstein breed (166±23 d in milk, 23.5±3.7 kg of milk/d; means ± SD). The cows were divided into a pasture and a confinement group (PG and CG, respectively). The CG stayed on a TMR-based diet (35% corn silage, 35% grass silage, 30% concentrate; DM basis), whereas the PG was gradually transitioned from a TMR- to a pasture-based ration (wk 1=TMR-only, wk 2=3 h/d on pasture, wk 3 and 4=12 h/d on pasture, wk 5-10=pasture-only). A continuous grazing system was implemented on a ryegrass dominated pasture and temperature humidity indices were assessed based on continuous recording of temperature and humidity indoors as well as outdoors. Dry matter intake (DMI) from TMR, milk production, body weight (BW), and body condition score decreased as soon as the PG had partial access to pasture. Milk production and BW decreased even further in the first week on a full grazing ration, but thereafter BW increased again and milk production stabilized. The DMI estimation using the n-alkane method in wk 7 and 9 revealed an increase in DMI from pasture between the 2 time points and indicates an adaptation of grazing behavior and metabolism over several weeks. Increased serum β-hydroxybutyrate and fatty acids concentrations at several time points, as well as a continuous body condition score decrease during the whole course of the trial, indicate an energy deficit in the PG. A significant correlation between serum glucose concentrations and the temperature humidity indices was observed. An increase in serum and milk urea concentrations as well as an increase in the urine total N to creatinine ratio occurred in the PG. To assess possible negative effects of the ration change on metabolic and liver health, different clinical chemistry variables and complete blood counts were assessed. No biologically relevant changes were observed for serum albumin, total protein, cholesterol, aspartate transaminase, γ-glutamyltransferase, and glutamate dehydrogenase concentrations, as well as for white and red blood cell counts.

Effects of elevated parameters of subclinical ketosis on the immune system of dairy cows: in vivo and in vitro results

Using an established model in which subclinical ketosis is induced, the response of differential blood counts and levels of various haematological variables, including the inflammatory marker haptoglobin (Hp), were tested over the last six weeks of parturition until the 56th day post-partum in cows with lower or higher body condition scores (LBC and HBC, respectively; n = 9/group). Animals in the HBC group evidenced subclinical ketosis whereas LBC animals were metabolically healthy. For in vitro examination with ß-hydroxybutyrate (BHB) as a further stimulus, peripheral blood mononuclear cell (PBMC) counts of cows with and without subclinical ketosis (n = 5/group) were observed. Counts of leucocytes, granulocytes and lymphocytes (LY) peaked at day 1 post-partum in HBC cows, with a more marked increase in heifers. In subclinical ketosis LY count increased again, with significantly higher values in the HBC group. The red blood cell (RBC) profile was affected by parity (counts were higher in heifers). Hp showed a positive linear correlation with BHB and non-esterified fatty acids (NEFA; R2 = 0.41). PBMC from cows that were not pre-stressed with subclinical ketosis were more sensitive to increasing levels of BHB in vitro, as evidenced by both their higher proliferative capability and increased release of nitric oxide (NO). In summary, cows with subclinical ketosis showed a heightened immune response compared with metabolically healthy individuals, based on increased LY counts, increasing stimulative properties of PBMC and a relationship between Hp and typically increased values of BHB and NEFA. Concentrations of BHB in vivo during subclinical ketosis did not alter the proliferative capability of bovine PBMC in vitro, which was first significantly decreased at a dosage of 5 mM BHB.

Effects of Long-term Graded L-arginine Supply on Growth Development, Egg Laying and Egg Quality in Four Genetically Diverse Purebred Layer Lines

The present study was conducted to examine effects of long-term graded L-arginine supply on growth development, egg laying and egg quality in four genetically diverse purebred layer lines. The study comprised a rearing trial from hatch to week 16 and a following laying performance trial from week 17 to 41. After hatch 150 one-day-old female chicks of each genotype were distributed to three diets. The experimental diets were equivalent to 70, 100 and 200% L-arginine of age-specific recommended level (National Research Council, 1994) and were offered ad libitum to chicks (hatch to week 7), pullets (week 8 to 16) and hens (week 17 to 41). However, hens’ diets were quite low in crude protein. After a pre-laying period from week 17 to 21 thirty-six pullets of each group were used further in the laying performance trial. Independent of chickens genetic background, insufficient L-arginine supply caused lower body weight, daily weight gain and daily feed intake during the rearing (p<0.001) and induced lower laying intensity and daily egg mass production in the laying period (p<0.05). Parameters fitted to Gompertz function suggested higher adult body weight in L-arginine supplemented birds compared to insufficient supplied ones (p<0.01). Groups fed with insufficient L-arginine reached age of maximum daily weight gain later and showed lowest maximum daily weight gain (p<0.001). As a consequence of limitations in dietary L-arginine and crude protein, high performing genotypes decreased strongly in body weight, daily feed intake and performance compared to the low performing genotypes. In conclusion, L-arginine modified the amount of weight gain and feed intake, especially in growing chicks and pullets independent of genetic background. The high performing hens were more nutritionally stressed than the low performing ones, because concentrations of dietary crude protein were relatively low.