Glucogenic Diet Research Articles

Discrimination of Lipogenic or Glucogenic Diet Effects in Early-Lactation Dairy Cows Using Plasma Metabolite Abundances and Ratios in Combination with Machine Learning.

During early lactation, dairy cows have a negative energy balance since their energy demands exceed their energy intake: in this study, we aimed to investigate the association between diet and plasma metabolomics profiles and how these relate to energy unbalance of course in the early-lactation stage. Holstein-Friesian cows were randomly assigned to a glucogenic (n = 15) or lipogenic (n = 15) diet in early lactation. Blood was collected in week 2 and week 4 after calving. Plasma metabolite profiles were detected using liquid chromatography-mass spectrometry (LC-MS), and a total of 39 metabolites were identified. Two plasma metabolomic profiles were available every week for each cow. Metabolite abundance and metabolite ratios were used for the analysis using the XGboost algorithm to discriminate between diet treatment and lactation week. Using metabolite ratios resulted in better discrimination performance compared with the metabolite abundances in assigning cows to a lipogenic diet or a glucogenic diet. The quality of the discrimination of performance of lipogenic diet and glucogenic diet effects improved from 0.606 to 0.753 and from 0.696 to 0.842 in week 2 and week 4 (as measured by area under the curve, AUC), when the metabolite abundance ratios were used instead of abundances. The top discriminating ratios for diet were the ratio of arginine to tyrosine and the ratio of aspartic acid to valine in week 2 and week 4, respectively. For cows fed the lipogenic diet, choline and the ratio of creatinine to tryptophan were top features to discriminate cows in week 2 vs. week 4. For cows fed the glucogenic diet, methionine and the ratio of 4-hydroxyproline to choline were top features to discriminate dietary effects in week 2 or week 4. This study shows the added value of using metabolite abundance ratios to discriminate between lipogenic and glucogenic diet and lactation weeks in early-lactation cows when using metabolomics data. The application of this research will help to accurately regulate the nutrition of lactating dairy cows and promote sustainable agricultural development.

Effects of Feeding Glucogenic and Lipogenic Diets on Performance and Blood Parameters of Transition Dairy Cows and Their Calves

Introduction: Several studies have explored the impact of diet type on energy sources. The current study aimed to evaluate the impact of feeding glucogenic versus lipogenic diets to Holstein dairy cows during the close-up period on cows' performances and their calves' growth parameters. Materials and methods: Twenty-four Holstein dairy cows with an average parity of 3 selected for the study, starting 21 days before expected calving. The cows were divided into three groups based on a randomized complete block design including a Control diet (glucogenic diet, Glu), a low lipogenic diet (Llip) with 25% barley grain replaced by beet pulp, and a high lipogenic diet (Hlip) with 50% barley grain replaced by beet pulp. Daily recording of dry matter intake (DMI) was conducted, with blood samples collected on the day of parturition in cows and days 1, 2, 7, and 21 of calves age. In dairy cows, both the quality and quantity of colostrum were determined. Additionally, performance variables including feed intake, average daily gain, and skeletal parameters such as shoulder height, Hip height, and body length were measured. Blood parameters, such as glucose, triglyceride, and concentrations of certain liver enzymes, including alkaline phosphatase (ALP), serum glutamic-pyruvic transaminase (SGPT), and serum glutamate oxaloacetate transaminase (SGOT) were recorded in calves. Results: The increase of beet pulp in the prepartum diet led to a significant increase in DMI. Colostrum yield and constituents (protein, lactose, and solids nonfat percentage) decreased with an increase in beet pulp level and the differences between Glu and Hlip were significant. Performance parameters of the calves were similar across all treatments, except skeletal growth. Calves that were fed the Hlip diet showed a lower shoulder height compared to those fed the Glu diet. Blood glucose was significantly higher in cows and their offspring that were fed Llip diets compared to other groups. The concentration of liver enzymes, including ALP, SGPT, and SGOT was not affected by treatments. Conclusion: Substituting barley grain with beet pulp as a lipogenic component may enhance dry matter intake in periparturient dairy cows. However, it did not show a notable impact on offspring performance.

Acute phase reaction to lipopolysaccharide-induced mastitis in early lactation dairy cows fed nitrogenic, glucogenic, or lipogenic diets

The availability of certain macronutrients is likely to influence the capacity of the immune system. Therefore, we investigated the acute phase response to intramammary (i.mam.) lipopolysaccharide (LPS) in dairy cows fed a nitrogenic diet (n = 10) high in crude protein, a glucogenic diet (n = 11) high in carbohydrates and glucogenic precursors, or a lipogenic diet (n = 11) high in lipids. Thirty-two dairy cows were fed one of the dietary concentrates directly after calving until the end of trial at 27 ± 3 days in milk (mean ± standard deviation). In wk 3 of lactation, 20 µg of LPS was i.mam. injected in one quarter, and sterile NaCl (0.9%) in the contralateral quarter. Milk samples of the LPS-challenged and control quarter were taken hourly from before (0 h) until 9 h after LPS challenge and analyzed for milk amyloid A (MAA), haptoglobin (HP), and IL-8. In addition, blood samples were taken in the morning, and composite milk samples at morning and evening milkings, from 1 d before until 3 d after LPS challenge, and again on d 9, to determine serum amyloid A (SAA) and HP in blood, and MAA and HP in milk. The mRNA abundance of various immunological and metabolic factors in blood leukocytes was quantified by quantitative reverse-transcription PCR from samples taken at -18, -1, 6, 9, and 23 h relative to LPS application. The dietary concentrates did not affect any of the parameters in blood, milk, and leukocytes. The IL-8 was increased from 2 h, HP from 2 to 3 h, and MAA from 6 h relative to the LPS administration in the milk of the challenged quarter and remained elevated until 9 h. The MAA and HP were also increased at 9 h after LPS challenge in whole-udder composite milk, whereas HP and SAA in blood were increased only after 23 h. All 4 parameters were decreased again on d 9. Similar for all groups, the mRNA abundance of HP and the heat shock protein family A increased after the LPS challenge, whereas the mRNA expression of the tumor necrosis factor α and the leukocyte integrin β 2 subunit (CD18) were decreased at 6 h after LPS challenge. The glucose transporter (GLUT)1 mRNA abundance decreased after LPS, whereas that of the GLUT3 increased, and that of the GLUT4 was not detectable. The mRNA abundance of GAPDH was increased at 9 h after LPS and remained elevated. The acute phase protein response was detected earlier in milk compared with blood indicating mammary production. However, immunological responses to LPS were not affected by the availability of specific macronutrients provided by the different diets.

Ruminal tissue uptake of amino acids in Holstein cows when supply of nutrients within the rumen differs

Characterisation of amino acid (AA) use by the ruminal vein-drained viscera (RDV) has not been assessed in vivo in dairy cattle, and thus, the extent of ruminal AA use from arterial and postabsorptive blood supplies is unclear. Understanding the complete use of AA by the splanchnic bed may lead to alternative feeding programmes that maximise animal N efficiency. The objective of this work was to determine how different nutritional manipulations affect RDV net appearance and apparent affinity for arterial AA in lactating dairy cattle. Data from two arterio-venous (A-V) difference studies, that used a common set of multicatheterised lactating Holstein cows, assigned to different nutritional treatments, were used to assess ruminal metabolism. Study 1 consisted of three dietary treatments at calving [an alfalfa-glucogenic diet, a glucogenic diet (GLCG), or a ketogenic diet (KETO)] to investigate the effects of dietary nutrients and increasing intake postpartum on RDV metabolism of AA at −14, +4, +15, and +29 days relative to calving (DRTC). Study 2 consisted of two dietary levels of CP (17 or 13%) and three ruminal buffers (ammonia, butyrate, and control) to investigate the level of dietary CP and ruminal fermentation products on RDV metabolism of AA. Blood was collected at 9, 20, and 30 min after buffer administration. Regardless of dietary nutrients or fermentation products present in ruminal fluid, net RDV uptake was positive for most AA, excepting Asp, Cys, Glu, and Ser, which were consistently negative. The general positive net uptakes indicate that any AA potentially absorbed from the rumen were not adequate to meet apparent needs. Ruminal plasma flow and net RDV uptake of Trp, Ala, Gly, and Pro increased linearly with increased DRTC. Feeding KETO or GLCG diets increased ruminal plasma flow, and net RDV uptake of Thr and Gly. Feeding high CP diets increased ruminal uptake of Leu, Phe, and Val. The increased AA uptakes were partially driven by increased plasma flow, however, tissue affinity as reflected in clearance rates also increased or tended to for Met, Trp, Ala, Gly, Pro, and Tyr suggesting that changes in RDV uptake were regulated and not due solely to mass action. In conclusion, splanchnic tissue bed responses to dietary and washed rumen conditions were in part driven by changes in RDV nutrient demand and metabolic activity. The adaptive responses alter the fraction of absorbed AA utilised for non-productive purposes and thus the efficiency of conversion of those AA to product.

Glucogenic and lipogenic diets affect in vitro ruminal microbiota and metabolites differently.

This study was conducted to evaluate the effects of two glucogenic diets (C: ground corn and corn silage; S: steam-flaked corn and corn silage) and a lipogenic diet (L: sugar beet pulp and alfalfa silage) on the ruminal bacterial and archaeal structures, the metabolomic products, and gas production after 48 h in vitro fermentation with rumen fluid of dairy cows. Compared to the C and S diets, the L dietary treatment leaded to a lower dry matter digestibility (DMD), lower propionate production and ammonia-nitrogen concentration. The two glucogenic diets performed worse in controlling methane and lactic acid production compared to the L diet. The S diet produced the greatest cumulative gas volume at any time points during incubation compared to the C and L diet. The metabolomics analysis revealed that the lipid digestion especially the fatty acid metabolism was improved, but the amino acid digestion was weakened in the L treatment than in other treatments. Differences in rumen fermentation characteristics were associated with (or resulting from) changes in the relative abundance of bacterial and archaeal genera. The rumen fluid fermented with L diet had a significantly higher number of cellulolytic bacteria, including the genera of Ruminococcus, Butyrivibrio, Eubacterium, Lachnospira, unclassified Lachnospiraceae, and unclassified Ruminococcaceae. The relative abundances of amylolytic bacteria genera including Selenomonas_1, Ruminobacter, and Succinivibrionaceae_UCG-002 were higher in samples for diets C and S. The results indicated that the two glucogenic diets leaded to a higher relative abundance of bacteria which functions in succinate pathway resulting in a higher propionate production. The steam-flaked corn diet had a higher gas production and lower level of metabolites in fatty acids and amino acids. Most highly abundant bacteria were observed to be not sensitive to dietary alterations of starch and fiber, except for several amylolytic bacteria and cellulolytic bacteria. These finding offered new insights on the digesting preference of ruminal bacteria, which can assist to improve the rumen functioning.

Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro.

AimsThis study was to investigate the effect of different ratios of glucogenic to lipogenic nutrients on rumen fermentation and the corresponding ruminal bacterial communities.Methods and ResultsFour diets, including glucogenic diet (G), lipogenic diet (L), two mixed diets: GL1 (G: L = 2 : 1) and GL2 (G:L = 1 : 2), served as substrates and were incubated with rumen fluid in vitro. The results revealed that the gas production, dry matter digestibility and propionate proportion were significantly increased by the G diet than others. The G diet increased the bacterial genera of Succinivibrionaceae_UCG_002, Succinivibrio, Selenomonas_1 and Ruminobacter but decreased some cellulolytic bacteria including the Eubacterium and several genera in family Ruminococcaceae than others.ConclusionsWhen the glucogenic nutrient was above 1/3 of the dietary energy source among the four diets, the in vitro incubation had a higher feed digestibility and lower acetate to propionate ratio. Bacterial genera, including Selenomonas, Succinivibrio, Ruminobacter, certain genera in Ruminococcaceae, Christensenellaceae_R‐7_group and Eubacterium, were more sensitive to the glucogenic to lipogenic nutrients ratio.Significance and Impact of the StudyThe present study provides a new perspective about the effect of dietary glucogenic to lipogenic ingredient ratios on rumen metabolism by comparing end‐products, gas production and bacterial composition via an in vitro technique.

Feeding of bakery by-products in the replacement of grains enhanced milk performance, modulated blood metabolic profile, and lowered the risk of rumen acidosis in dairy cows

Leftover bakery by-products (BP) from bakeries and supermarkets may serve as energy-rich ingredient in ruminant diets. The aim of the present study was to evaluate the effect of the successive substitution of cereal grains by BP on dry matter (DM) intake, milk production, and metabolic health as well as ruminal pH and eating and chewing behavior of dairy cows. Twenty-four lactating Simmental cows (149 ± 22.3 d in milk, lactation number 2.63 ± 1.38, 756 ± 89.6 kg of initial body weight) were fed a total mixed ration containing a 50:50 ratio of forage to concentrate throughout the experiment (35 d). During the first week, all cows received a control diet (without BP) as a baseline (d -7 to 0). In the next 4 wk (d 1 to 28), cows were allocated to 3 groups differing in the BP concentrations of diets [0% BP (CON), 15% BP, and 30% BP on a DM basis]. The DM intake and reticuloruminal pH were continuously measured. Blood and milk samples were taken every week, but only results from the experimental period (d 21 and 28) were used for statistical analyses, whereas results from the baseline were considered covariates. Diet analyses showed that BP inclusion increased the ether extract and sugar contents, whereby starch and neutral detergent fiber decreased. Experimental data showed that feeding BP in the diet increased DM intake. Furthermore, the cows fed 30% BP produced roughly 4 kg/d more milk and energy-corrected milk than the CON cows. The milk urea nitrogen was lower in cows fed the BP. Feeding BP reduced the blood glucose and insulin concentrations, whereas nonesterified fatty acids, β-hydroxybutyrate, and cholesterol increased linearly. Cows fed 15% BP had the shortest period of time in which ruminal pH was below 5.8, in contrast to CON cows (+188 min/d). Taken together, the results suggest that the inclusion of up to 30% BP in the diets of mid-lactation dairy cows shifted the nutrient profile from a glucogenic diet to a lipogenic diet, holding the potential to enhance performance and lower the risk of subacute ruminal acidosis in dairy cows.

Effects of Two Different Energy Sources in Total Mixed Diets on the Performances and Blood Metabolites of Lactating Boerka Goats

Lactating goats are prone to negative energy status due to increased body fat reserve mobilization to support the high energy requirement of milk production. The study was aimed to investigate the responses of the lactating goat on diets provided in total-mixed ration differing in the energy sources. The experiment was conducted using a total of 35 does having 2-3 parities and an average bodyweight of 30.3±4.48 kg and BCS of 2.5 ± 0.05 on a scale basis of 1 to 5. Animals were allocated to one of five dietary treatments (seven animals/treatment) formulated to be iso-nitrogen dan iso-calory in a total mixed ration. Cassava meal was used as the source of glucogenic energy and bergafat as the main source of lipogenic energy. There were no DM intake differences (P>0.05) between the glucogenic diet (1.49% and 2.28% fat), but significant increases (P<0.05) in DM intake were observed in goats fed lipogenic diets (fat content range from 4.7 to 7.5%). All animals gained during the lactation period with ADG ranged from 15 to 46 g, indicating that all experimental animals were in positive energy balances. Goat receiving more glucogenic diets gained least and having higher FCR compared to those receiving lipogenic diet (P<0.05). Body condition scores were also improved in lactating goat received more lipogenic diets. Blood glucose and blood urea concentration was not affected by diet treatments and lactation period (P>0.05) and ranged from 37 to 43 mg/dl and 39 to 51 mg/dl, respectively. Numerically, however, the blood glucose and urea level linearly increased as the diet becoming more lipogenic due to the increased feed intake. It is concluded that lactating goats offered diets with lipogenic energy sources (7.5% fat content) presented in pelleted total mixed-ration during the entire lactation period had a higher dry matter and nutrient intakes, body weight gain and body condition score compared to those fed diets with glucogenic energy source.

Relationships between uterine health and metabolism in dairy cows with different dry period lengths

The first objective of this study was to evaluate effects of dry period (DP) length and dietary energy source on ovarian activity, uterine health status, pregnancy rate, and days open in dairy cows in the second subsequent lactation after implementation of DP length and dietary treatments. The second objective was to determine relationships of uterine health status with ovarian activity, milk yield, energy balance (EB), and metabolic status in dairy cows. Holstein-Friesian dairy cows (n = 167) were assigned randomly to 1 of 3 DP lengths (0-, 30-, or 60-d) and 1 of 2 early lactation diets (glucogenic or lipogenic diet) for 2 subsequent lactations. Milk samples were collected three times a week. At least two succeeding milk samples with concentration of progesterone ≥2 ng/mL were used to indicate the occurrence of luteal activity. Vaginal discharge was scored in wk 2 and 3 after calving to evaluate uterine health status and cows were classified as having a healthy uterine environment [HU, vaginal discharge score (VDS) = 0 or 1 in both wk 2 and 3], a recovering uterine environment (RU, VDS = 2 or 3 in wk 2 and VDS = 0 or 1 in wk 3), or a non-recovering uterine environment (NRU, VDS = 2 or 3 in wk 3). Cows were monitored for milk yield, dry matter intake (DMI), and blood was sampled weekly to determine metabolic status from calving to wk 3 postcalving. Dry period length was not related with uterine health status in early lactation, pregnancy rate, or days open in dairy cows. Independent of DP length, feeding a glucogenic diet shortened the interval from calving to onset of luteal activity (25.3 vs. 31.0 d, P = 0.04), but decreased pregnancy rate compared with a more lipogenic diet (68.2 vs. 78.1 d, P = 0.03). In the first 3 wk after calving, cows with a NRU had lower milk yield (36.8 vs. 36.8 vs. 32.4 kg for cows with a HU, RU, or NRU, respectively; P < 0.01) and lower DMI than cows with a HU or RU. Cows with a RU had lower plasma glucose and insulin concentrations than cows with a NRU or HU. In conclusion, DP length did not influence fertility measures and uterine health status in the second subsequent lactation after implementation of DP length treatments. Independent of DP length, feeding a glucogenic diet leaded to earlier ovulation postcalving, but decreased pregnancy rate compared with a more lipogenic diet. In addition, a healthy uterine environment was related to greater milk yield and better metabolic status, independent of DP length.

In Vitro Yield of Microbial-N from Fermentation of Glucogenic and Lipogenic Diets Provided by Different Sources of Rumen Degradable Amino Acids

This experiment was conducted to evaluate the effects of different sources of rumen degradable amino acids, soybean meal versus a commercial source of hydrolyzed cottonseed cake with low molecular weight (Fortid®), on the in vitro ruminal fermentation responses and the microbial nitrogen yield of glucogenic (n=8) and lipogenic (n=8) diets. An in vitro gas production technique was used to determine the differences in microbial nitrogen yield of the diets. Sources of grain including barely and corn were used in the glucogenic diets as grinded or steam flaked, while in the lipogenic diets, corn silage, sugar beet pulp, linseed and prill fat were used to provide the energy needed for rumen fermentation. The experiment was a randomized design including two types of diets × two sources of rumen degradable amino acids factorial arrangement. The gas produced from the fermentable fraction (b) was higher for the lipogenic diets containing corn silage and F than those for the others. The fraction (b) and microbial nitrogen to diet nitrogen ratio were greater (p<0.05) for Fortid® versus soybean meal. The true substrate digestibility of glucogenic diets were significantly higher (p<0.05) compared to those of lipogenic diets. Both the grain sources used as steam flaked caused an increase in the rate of gas produced (c) and microbial nitrogen to diet nitrogen ratio. There were significant interactions (p<0.005) of the type of diets with either soybean meal or Fortid® on microbial nitrogen to diet nitrogen. The results indicated that pre-hydrolyzed protein sources which are rich in low molecular weight peptides may be considered as candidates to improve rumen feed fermentation and microbial nitrogen production with both glucogenic and lipogenic diets. This conclusion was arrived at from the different patterns of action of soybean meal and Fortid® in the present in vitro rumen fermentation responses.

Effects of dry period length and dietary energy source on milk yield, energy balance, and metabolic status of dairy cows over 2 consecutive years: Effects in the second year

The objective of the current study was to evaluate the effect of dry period (DP) length on milk yield, energy balance (EB), and metabolic status in cows fed a lipogenic or glucogenic diet in the second year after implementation of DP and dietary treatments. Holstein-Friesian dairy cows (n=167) were assigned randomly to 1 of 3 DP lengths (0, 30, or 60d) and 1 of 2 early lactation diets (glucogenic or lipogenic) for 2 consecutive years. Results of the first year were reported previously. In the second year, 19 cows in the 0-d DP group were attributed to a new group (0→67d DP) because these cows had a milk yield of <4kg/d at least 30d before expected calving date and were dried off. Milk yield was recorded and EB was calculated from wk –8 to 9 relative to calving. Blood samples were taken weekly from wk –3 to 8 relative to calving. Liver samples were taken in wk –2, 2, and 4 relative to calving. At the onset of lactation, cows with a 0-d or 0→67-d DP had greater body condition score (BCS) than cows with a 60-d DP. During the first 9wk, cows with a 0- or 30-d DP produced 5.0 and 4.3kg less milk per day, respectively, but had similar EB compared with cows with a 60-d DP. Cows with a 0- or 30-d DP produced additional milk precalving, which could compensate milk yield losses in the first 9wk postcalving. Cows with a 0-d DP did not have milk yield losses or improve EB in the second year as much as in the first year. Cows with a 0-d DP had greater plasma insulin and insulin-like growth factor-I (IGF-I) and lower liver triacylglycerol concentrations than cows with other DP lengths. Cows with a 0→67-d DP had lower EB, and greater plasma free fatty acids (FFA) and β-hydroxybutyrate (BHB) concentrations than cows with other DP lengths. Feeding a glucogenic diet increased plasma glucose, IGF-I, and insulin concentrations, and decreased plasma FFA, BHB, and urea concentrations compared with a lipogenic diet, independent of DP length. In conclusion, omitting the DP or feeding a glucogenic diet improved metabolic status in early lactation of the second year after implementation of DP length and dietary treatments, although effects of omitting the DP were less pronounced in the second year than in the first year. The less pronounced improvement of EB in the second year was related to the high BCS at the onset of lactation and reduced milk yield losses in cows with a 0-d DP.

Nutrition, Metabolic Status and Reproductive Efficiency in Dairy Herds

Nutrition of transition period in dairy cows dramatically increases requirements for energy, glucose, amino acids and other nutrients in dairy cows and, parallel to that, feed intake is depressed. An insufficient or imbalanced nutrient intake might lead to the malfunction of organs, causing reproductive failure. To minimize the metabolic/reproductive damage caused by negative energy balance (NEBAL), feeding of a glucogenic and lipogenic diet containing fat-enriched supplements is recommended. In heat-stressed dairy cows, the reduction of dry matter intake causes an energy deficit, thereby accentuating NEBAL. Heat stress may also have a direct impact on oocyte quality due to the high ovarian temperatures. The intrauterine environment is also compromised in heat-stressed cows, with reduced blood flow to the uterus and increased uterine temperature; this may impair embryonic development, increase early embryonic loss and reduce the proportion of successful inseminations. Postpartum NEBAL suppresses immune function and promotes metabolic disorders, potentially explaining relationships between infectious and noninfectious transition disorders. In postpartum dairy cows, pathologic ovarian phenomena including ovulatory (cystic corpora lutea) and non-ovulatory (follicular and luteal cysts) forms frequently occur causing decreased fertility. The main objective of this review was summarizing the most relevant information regarding nutrition and reproduction in dairy cows.

Effect of energy sources on the milk production and reproduction of lactating Holstein cows

ABSTRACTThe objective of the study was to evaluate the effect of energy sources on milk production and reproduction of dairy cows on a pasture-based feeding system. Following parturition, 201 Holstein cows from the Elsenburg herd were fed ad libitum cultivated irrigated kikuyu-ryegrass pastures for 22 weeks. Cows were divided into three groups according to concentrate supplementation, of which the energy was provided by starch and/or fat. These were grouped according to parity, body live weight and milk yield of previous lactation. The control consisted of low levels of standard supplement while treatments consisted of supplements of high starch-low fat (HSLF) and high starch-low fat low starch-high fat (HSLF-LSHF) given to cows on pastures. Treatment P-HSLF was a glucogenic regime made of maize. Treatment P-HSLF-LSHF was a high starch/high fat combination treatment, whereby a glucogenic diet was offered for the first 60 days of lactation as per treatment P-HSLF and followed from 61 to 154 days by a lipog...

Relationship between metabolism and ovarian activity in dairy cows with different dry period lengths

The objectives of the present study were to evaluate the effects of dry period length on ovarian activity in cows fed a lipogenic or a glucogenic diet within 100 days in milk (DIM) and to determine relationships between ovarian activity and energy balance and metabolic status in early lactation. Holstein-Friesian dairy cows (n = 167) were randomly assigned to one of three dry period lengths (0, 30, or 60 days) and one of two diets in early lactation (glucogenic or lipogenic diet) resulting in a 3 × 2 factorial design. Cows were monitored for body condition score, milk yield, dry matter intake, and energy balance from calving to week 8 postpartum, and blood was sampled weekly from 95 cows from calving to week 8 postpartum. Milk samples were collected three times a week until 100 DIM postpartum for determination of progesterone concentration. At least two succeeding milk samples with progesterone concentration of 2 ng/mL or greater were used to indicate the occurrence of luteal activity. Normal resumption of ovarian cyclicity was defined as the onset of luteal activity (OLA) occurring at 45 DIM or less, followed by regular ovarian cycles of 18 to 24 days in length. Within 100 DIM postpartum, cows with a 0-day dry period had greater incidence of normal resumption of ovarian cyclicity (53.2%; 25 out of 47 cows) compared with cows with a 60-day dry period (26.0%; 13 out of 50 cows, P = 0.02). Independent of dry period length or diet, cows with OLA at less than 21 DIM had a greater body condition score during weeks 1 and 2 (P = 0.01) and weeks 1 through 8 (P = 0.01) postpartum compared with cows with OLA at greater than 30 DIM. Cows with the first ovarian cycle of medium length (18–24 days) had greater energy balance (P = 0.03), plasma concentrations of insulin (P = 0.03), glucose (P = 0.04), and insulin-like growth factor I (P = 0.04) than cows with long ovarian cycle lengths (>24 days) but had lower plasma β-hydroxybutyrate (P < 0.01) and liver triacylglycerol (P = 0.02) concentrations than cows with short ovarian cycle lengths (<18 days) during weeks 1 through 8 postpartum. Diet did not affect the measured ovarian activity variables within 100 DIM. In conclusion, omitting the dry period (0 days) increased the incidence of normal resumption of ovarian cyclicity in dairy cows within 100 DIM compared with a conventional dry period (60 days). Short (<18 days) or long (>24 days) ovarian cycles during the first ovarian cycle postpartum were associated with severe negative energy balance and poor metabolic status in early lactation.

Effects of dry period length and dietary energy source on metabolic status and hepatic gene expression of dairy cows in early lactation

In a prior study, we observed that cows with a 0-d dry period had greater energy balance and lower milk production compared with cows with a 30- or 60-d dry period in early lactation. The objective of the current study was to evaluate the influence of dry period length on metabolic status and hepatic gene expression in cows fed a lipogenic or glucogenic diet in early lactation. Holstein-Friesian dairy cows (n=167) were assigned randomly to 3×2 factorial design with 3 dry period lengths (n=56, 55, and 56 for 0-, 30-, and 60-d dry, respectively) and 2 early lactation diets (n=84 and 83 for glucogenic and lipogenic diet, respectively). Cows were fed a glucogenic or lipogenic diet from 10d before the expected calving date and onward. The main ingredient for a glucogenic concentrate was corn, and the main ingredients for a lipogenic concentrate were sugar beet pulp, palm kernel, and rumen-protected palm oil. Blood was sampled weekly from 95 cows from wk 3 precalving to wk 8 postcalving. Liver samples were collected from 76 cows in wk −2, 2, and 4 relative to calving. Liver samples were analyzed for triacylglycerol concentrations and mRNA expression of 12 candidate genes. Precalving, cows with a 0-d dry period had greater plasma β-hydroxybutyrate, urea, and insulin concentrations compared with cows with a 30- or 60-d dry period. Postcalving, cows with a 0-d dry period had lower liver triacylglycerol and plasma nonesterified fatty acids concentrations (0.20, 0.32, and 0.36mmol/L for 0-, 30-, and 60-d dry period, respectively), greater plasma glucose, insulin-like growth factor-I, and insulin (24.38, 14.02, and 11.08µIU/mL for 0-, 30-, and 60-d dry period, respectively) concentrations, and lower hepatic mRNA expression of pyruvate carboxylase, compared with cows with a 30- or 60-d dry period. Plasma urea and β-hydroxybutyrate concentrations were greater in cows fed a lipogenic diet compared with cows fed a glucogenic diet. In conclusion, cows with a 0-d dry period had an improved metabolic status in early lactation, indicated by lower plasma concentrations of nonesterified fatty acids, greater plasma concentrations of glucose, insulin-like growth factor-I, and insulin, and lower mRNA expression of pyruvate carboxylase in the liver, compared with cows with a 30- or 60-d dry period. Independent of dry period length, the glucogenic diet also improved the metabolic status compared with the lipogenic diet.

Diets rich in starch increase the posthepatic availability of amino acids in dairy cows fed diets at low and normal protein levels

Five mid-lactation multicatheterized Jersey cows were used in a 4×4 Latin square design to investigate whether the increase in milk N yield associated with diets rich in starch versus fiber could originate from changes in the splanchnic AA metabolism and if these changes depended upon the dietary crude protein (CP) content. Four isoenergetic diets were formulated to provide 2 different carbohydrate compositions [diets rich in starch (350g of starch and 310g of neutral detergent fiber/kg of dry matter) versus rich in fiber (45g of starch and 460g of neutral detergent fiber/kg of dry matter)] crossed by 2 different CP contents (12.0 vs. 16.5% CP). At the end of each treatment period, 6 hourly blood samples were collected from the portal and hepatic veins as well as the mesenteric artery to determine net nutrient fluxes across the portal-drained viscera (PDV), liver, and total splanchnic tissues. Dry matter and calculated energy intake as well as total absorbed energy were similar across treatments. However, the net portal appearance (NPA) of acetate, total volatile fatty acids, and β-hydroxybutyrate were higher with diets rich in fiber versus starch, whereas that of oxygen, glucose, butyrate, and insulin were lower. Concomitant to these changes, the percentage of N intake recovered as total AA (TAA) in the portal vein was lower for diets rich in fiber versus starch (42.3 vs. 51.4%, respectively), without, however, any difference observed in the NPA of the main AA used as energy fuels by the PDV (Glu, Gln, and Asp). Despite a higher NPA of TAA with starch versus fiber diets, no differences in the net hepatic flux of TAA, essential and nonessential AA were observed, resulting in a higher (+22%) net splanchnic release of AA and, hence, a greater (+7%) milk N yield. The net hepatic flux and hepatic fractional removal of none of the individual AA was affected as the main carbohydrate changed from fiber to starch, except for Gly and Lys, which were higher for the latter. After correcting for differences in NPA of TAA, the net hepatic uptake of TAA tended to be lower with starch versus fiber diets. The higher transfer of N from feed to milk with diets rich in starch is not the consequence of a direct sparing AA effect of glucogenic diets but rather the result of lower energy requirements by the PDV along with a higher microbial N flow to the duodenum. A better AA use by peripheral tissues with starch versus fiber diets was also hypothesized but more studies are warranted to clarify this issue.

Effects of timing to start lipogenic diet on productive and reproductive responses in periparturient dairy cows

The aim of this study was to evaluate productive, metabolic and ovarian responses of different timing to start lipogenic diet in dairy cows. Thirty-six multiparous cows were assigned randomly to 1 of 3 treatments in a completely randomized design. All cows were fed a similar glucogenic diet, 21 days before expected calving date. After parturition, they received a glucogenic diet until 42 days in milk (DIM; GGG) or shifted to a lipogenic diet at either 1 (GLL) or 21(GGL) DIM and remained on these diets until 42 DIM. After the day 42 postpartum, all cows returned to a common stall and received a mixed lipogenic and glucogenic (50:50) diet until 100 DIM. Postpartum dry matter intake (DMI) was lower (P<0.05) and body weight, body condition score, milk yield, milk protein, and milk lactose contents tended to be lesser (P<0.1) for the GLL group; however, negativity of energy balance, aspartate aminotransferase (AST), cholesterol, and urea concentrations were significantly higher (P<0.05). Glucose concentration and number of follicles ≥10mm diameter were significantly higher (P<0.05) but BHBA and NEFA concentrations were lower (P<0.05) for the GLL group compared to other two groups. For the GLL group days to ovulation and cervical diameter were significantly higher (P<0.05). The conclusion is that providing a lipogenic diet immediately after calving has negative effects on energy balance, metabolic status and follicular dynamics of dairy cows. However, offering a glucogenic diet during −21 to +42 days relative to calving was more effective in improving animal performance and ovarian activity. This strategy may be enhancing the pregnancy rate.

Effects of glucogenic and ketogenic feeding strategies on splanchnic glucose and amino acid metabolism in postpartum transition Holstein cows

Nine periparturient Holstein cows catheterized in major splanchnic vessels were used in a complete randomized design with repeated measurements to investigate effects of glucogenic and ketogenic feeding strategies on splanchnic metabolism of glucose and amino acids. At parturition, cows were assigned to 1 of 3 feeding strategies: a glucogenic diet (GLCG) based on sodium hydroxide treated wheat grain (56.5% of diet dry matter); a ketogenic diet (KETO) based on fodder beets (40.5% of diet dry matter); or an alfalfa-glucogenic strategy (ALF-GLCG) supplying 100% alfalfa (Medicago sativa L.) haylage at the day of parturition, followed by a 6-d linear shift to the GLCG diet. Samples were obtained 14d before expected parturition as well as at 4, 15, and 29d in milk (DIM). The net portal release of glucose was greatest with GLCG, reflecting the higher intake of ruminal escape starch with GLCG, as compared with a lower starch intake with KETO. Postpartum, the portal recovery of feed starch was greater (28±3%, mean ± SEM) with KETO as compared with GLCG (15±4%). At 4 DIM, the net hepatic release of glucose was greatest with KETO and least with ALF-GLCG, whereafter it increased as lactation progressed with ALF-GLCG and GLCG, but not with KETO. The high alfalfa haylage allowance at 4 DIM with the ALF-GLCG treatment induced the lowest net release of nutrients from the splanchnic tissues at 4 DIM. The hepatic removal of lactate as percent of total influx (mean ± SEM) increased from 27±3% prepartum to 56±3% at 4 DIM. The hepatic removal of lactate as percent of net portal release increased from 144±10% prepartum to 329±17% at 4 DIM with ALF-GLCG and KETO as compared with 242±20% in GLCG. No clear evidence for an amino acid sparing effect in splanchnic tissues from increasing small intestinal glucose absorption was observed. In conclusion, the glucogenic feeding strategy induced the highest glucogenic status among the tested feeding strategies due to greater release of glucose from splanchnic tissues. In contrast, the immediate postpartum high allowance of alfalfa haylage provided the lowest amount of nutrients from the splanchnic tissues, inducing low glucogenic status, pointing to the importance of allocating highly digestible diets to postpartum transition cows. Salvaging glucogenic carbon via interorgan transfer of lactate from peripheral tissues supported the immediate postpartum incremental increase in hepatic glucose release rather than hepatic catabolism of amino acids.

Effect of Dietary Starch or Micro Algae Supplementation on Rumen Fermentation and Milk Fatty Acid Composition of Dairy Cows

Two experiments with rumen-fistulated dairy cows were conducted to evaluate the effects of feeding docosahexaenoic acid (DHA; C22:6 n-3)-enriched diets or diets provoking a decreased rumen pH on milk fatty acid composition. In the first experiment, dietary treatments were tested during 21-d experimental periods in a 4×4 Latin square design. Diets included a control diet, a starch-rich diet, a bicarbonate-buffered starch-rich diet, and a diet supplemented with DHA-enriched micro algae [Schizochytrium sp., 43.0g/kg of dry matter intake (DMI)]. Algae were supplemented directly through the rumen fistula. The total mixed ration consisted of grass silage, corn silage, soybean meal, and a standard or glucogenic concentrate. The glucogenic and buffered glucogenic diet had no effect on rumen fermentation and milk fatty acid composition because, unexpectedly, no reduced rumen pH was detected. The algae diet had no effect on rumen pH but provoked decreased butyrate and increased isovalerate molar proportions in the rumen. In addition, algae supplementation affected rumen biohydrogenation of linoleic and linolenic acid as reflected in the modified milk fatty acid composition toward increased conjugated linoleic acid (CLA) cis-9 trans-11, CLA trans-9 cis-11, C18:1 trans-10, C18:1 trans-11, and C22:6 n-3 concentrations. Concomitantly, on average, a 45% decrease in DMI and milk yield was observed. Based on these drastic and impractical results, a second animal experiment was performed for 20 d in which 9.35g/kg of total DMI of algae were incorporated in the concentrate and supplemented to 3 rumen-fistulated cows. Algae concentrate feeding increased rumen pH, which was associated with decreased rumen short-chain fatty acid concentrations. Moreover, a different shift in rumen short-chain fatty acid proportions was observed compared with the first experiment because molar proportions of butyrate, isobutyrate, and isovalerate increased, whereas acetate molar proportion decreased. The milk fatty acid profile changed as in experiment 1. However, the decrease in DMI and milk yield was less pronounced (on average 10%) at this algae supplementation level, whereas milk fat percentage decreased from 47.9 to 22.0g/kg of milk after algae treatment. In conclusion, an algae supplementation level of about 10g/kg of DMI proved effective to reduce the milk fat content and to modify the milk fatty acid composition toward increased CLA cis-9 trans-11, C18:1 trans, and DHA concentrations.

Natural Antibodies Related to Energy Balance in Early Lactation Dairy Cows

The objectives of this study were to determine the presence of natural antibodies (NAb) in plasma and milk of individual dairy cows and to study the relation between NAb concentrations and energy balance (EB) and dietary energy source. Cows (n=76) were fed a mainly glucogenic, lipogenic, or a mixture of both diets (50:50 dry matter basis) from wk 3 before the expected calving date until wk 9 postpartum. Diets were isocaloric (net energy basis) and equal in intestinal digestible protein. Blood and milk were sampled weekly. Liver biopsies were taken in wk −2, 2, 4, and 6 relative to calving. Data are expressed as LSM±SEM. The NAb titers are expressed as the 2log values of the highest dilution giving a positive reaction. The NAb concentration in plasma binding either keyhole limpet hemocyanin (KLH) or Escherichia coli lipopolysaccharide (LPS) increased with parity. The NAb concentration binding KLH was greater for cows fed the glucogenic diet (9.63±0.08) compared with the lipogenic diet (9.26±0.08). In milk, cows fed the glucogenic diet had smaller NAb concentrations binding KLH (3.98±0.18) and LPS (2.88±0.17) compared with cows fed the mixed diet (KLH: 4.93±0.18; LPS: 3.70±0.17). The NAb concentration in plasma had a positive relation with energy balance variables: EB, dry matter intake, milk yield, and plasma cholesterol, whereas NAb concentration in milk had a negative relation with energy balance variables: EB, dry matter intake, and plasma cholesterol. Additionally, NAb concentrations in milk had a positive relation with plasma nonesterified fatty acid concentration and milk fat and protein percentage. There was a tendency for a positive relation of NAb concentration binding LPS in plasma and somatic cell count in milk. No significant relations were detected between NAb concentrations in milk or plasma and plasma β-hydroxybutyrate concentration and liver triacyl glyceride content. In conclusion, NAb are present in both milk and plasma of dairy cows peripartum and NAb concentrations increase with parity. Furthermore, our data indicate that a negative energy balance in dairy cows in early lactation can be associated with compromised innate immune function as indicated by decreased NAb concentration in plasma.