Interrelationship of growth hormone AluI polymorphism and hyperketonemia with plasma hormones and metabolites in the beginning of lactation in dairy cows

A polymorphic site of the growth hormone gene (AluI polymorphism) that results in an amino acid change at position 127 of the protein chain (leucine, L to valine, V) has been linked to differences in circulating metabolites and metabolic hormones of calves and bulls and to milk yield traits of lactating cows. Our objective was to investigate the interrelationship of this polymorphism with plasma concentrations of β-hydroxybutyrate, insulin, IGF-I and leptin in postpartum dairy cows. Blood samples were taken from clinically healthy, spring-calving, group-fed Holstein-Friesian cows (n = 257; 7 large-scale farms) 4–13 days after calving. Of all herds, 100 cows had plasma β-hydroxybutyrate levels above 1.2 mmol/l and 157 cows were normoketonemic. The proportion of valine carriers and LL cows was not different within groups of normo- and hyperketonemic animals. Genotype was not associated with plasma β-hydroxybutyrate, insulin, IGF-I and leptin levels either in all of the herds or in the two with the highest proportion of the valine allele carriers (n = 28, 72%). We found significantly lower insulin, IGF-I and leptin concentrations in the presence of hyperketonemia compared to normoketonemic cows. There were strong negative correlations between BHB and the other blood parameters, while insulin, IGF-I and leptin were positively related to each other. In conclusion, in the first two weeks after calving we could not demonstrate any effect of AluI polymorphism on plasma concentrations of β-hydroxybutyrate and metabolic hormones studied. Hyperketonemia was associated with a significant decrease in insulin, IGF-I and leptin blood levels. We infer that cows homozygous for the leucine allele or carrying the valine allele may have a similar endocrine and metabolic response to the challenge of increased nutrient demand early postpartum and that the presence of hyperketonemia is mainly linked to the hormonal and metabolic changes occurring at the onset of lactation.     

Targeted transcript analysis revealed association of suboptimal expression of certain endometrial immunity-related genes with disparate uterine diseases in zebu cows

The onset of uterine infection during postpartum period compromises uterine health, fertility, and productivity of dairy cattle. Endometrial innate immunity plays a key role in eliminating uterine infection and keeping the uterus healthy. Hence, the present study has been designed with the hypothesis that altered endometrial immune response around calving may compromise uterine health during postpartum period. Expression of interleukins (IL-1β, IL-6, IL-8, IL-10, and TNF-α), prostaglandin synthase (PGFS, PGES), and antimicrobial peptides (beta-defensins (BDEF-4, BDEF-5), lingual antimicrobial peptide (LAP), and calcium-binding proteins (S100A8, S100A9, and S100A12) in endometrial tissues on the day of calving was studied using qRT-PCR, and circulating concentrations of prostaglandin E and F metabolites (PGEM and PGFM) during peripartum period (on days ??7, ??4, ??1 (before calving), 0 (on the day of calving), +?1, +?4, and +?7 (post calving)) of normal (healthy) cows (n?=?11) that did not develop postpartum uterine infection and cows that developed puerperal metritis (n?=?7) and clinical endometritis (n?=?6) were studied. Endometrial expression of IL-1β, TNF-α, BDEF-4, BDEF-5, S100A8, S100A12, and PGFS was higher (P?<?0.05), and expression of IL-6, IL-8, IL-10, and PGES was lower (P?<?0.05) in normal (healthy) cows than puerperal metritic and clinical endometritic cows. The PGFM concentration in serum was high (P?<?0.05) on days 0, +?1, and +?4 of calving in puerperal metritic cows followed by normal and clinical endometritic cows. However, PGEM concentration in serum was high (P?<?0.05) during peripartum period in uterine-infected (puerperal metritic and clinical endometritic) cows compared with normal cows. From the above findings, it is concluded that higher constitutive expression of IL-1β, TNF-α, PGFS, BDEF-4, BDEF-5, S100A8, and S100A12 genes in the endometrium and lower concentration of PGEM during the period immediate to calving might be beneficial for uterine health of cows.

     

Subclinical ketosis in dairy cows: prevalence and risk factors in grazing production system

The purpose of this study was to estimate the prevalence of Subclinical ketosis (SCK) between 4 and 19 days in milk (DIM) in a grazing production system and investigate the importance of potential risk factors for SCK. This cross‐sectional study was conducted in dairy cows (n = 107), which had more of two parities. The concentration of β‐hydroxybutyric (BHB) in blood was quantified through a hand‐held meter. Potential risk factors evaluated were calving interval (CI), milk yield in previous lactation, metritis, dystocia, calf sex (male), parity (≤3 vs. ≥4) and pre‐partum body condition score (BCS ≤ 3.5 vs. ≥3.75). Prevalence of SCK was 10.3% (95% CI 4.7–15) between 4 and 19 DIM. Risk factors identified were the occurrence of both metritis and pre‐partum BCS ≥ 3.75. Cows with metritis had 4.9 (95% CI 1.17–20.98) times more risk of developing SCK than cows without metritis. And the cows with pre‐partum BCS ≥ 3.75 had 5.25 (95% CI 1.32–21.11) times more risk of developing SCK than cows with pre‐partum BCS ≤ 3.5. Metritis could induce a lower feed intake and promote the development of SCK. High pre‐partum BCS could induce a greater mobilization of body reserves altering liver function and aggravating post‐partum NEB. The results are indicative of the expected prevalence of SCK in grazing production system. Factors associated could help to identify cattle at risk of SCK and improve the management of strategies to limit the effects.     

Long‐term impact of puerperal metritis on the profiles of peripheral blood leukocytes in peripartum dairy cows

To determine the effects of puerperal metritis on the immune response, changes in the differential peripheral blood leukocyte counts were analyzed during the peripartum period in cows with or without metritis. Multiparous Holstein cows were examined for uterine health disorders and classified into two groups: healthy (n = 11) or metritis (n = 5) cows. The lymphocyte and monocyte counts and the proportion of CD8⁺ lymphocytes were higher in cows with metritis compared to healthy cows. Moreover, the effects of puerperal metritis on the lymphocyte counts and CD4⁺/CD8⁺ ratio persisted weeks after the uterine inflammation had self‐resolved. Taken together, the findings of the present study indicate the possible long‐term alterations of systemic immune responses in cows with puerperal uterine inflammation. © 2015 Japanese Society of Animal Science     

Metabolic parameters and their relationship to energy balance in multiparous Simmental,Brown Swiss and Holstein cows in the periparturient period as influenced by energy supply pre‐ and post‐calving

A study was conducted to evaluate the effects of three energy supply (E) levels [low (L), medium (M), high (H)], both pre‐partum (PRE) and post‐partum (POST), and their interactions on metabolic parameters and energy balance (EB) in dairy cows of three breeds. In both phases, E levels applied to a total of 81 multiparous cows of breeds Simmental (SI), Brown Swiss (BS) and Holstein–Friesian (HF; n = 27 for each breed) were 75%, 100% and 125% of recommendations of the German Society of Nutrition Physiology, using a 3 × 3 factorial arrangement of treatments. During the pre‐calving period, serum concentrations of non‐esterified fatty acids (NEFA) were higher for L_PRE cows, and glucose concentrations were elevated for H_PRE cows. During the lactation period, NEFA concentrations were greatest for treatment L_POST. Mean concentrations of β‐hydroxybutyrate (BHB) were highest for cows of the L_POST treatment, intermediate for M_POST and lowest for H_POST. Glucose concentrations were lower for L_POST cows. SI cows had lower BHB concentrations both pre‐ and post‐calving and higher glucose concentrations during early lactation than the other breeds. BHB concentration POST was highest for BS cows. Restricted feeding PRE resulted in a better energy status of cows fed above energy requirements POST (E_PRE × E_POST interaction). HF cows had a higher EB pre‐calving, whereas SI cows had a less negative EB during early lactation, compared with the other breeds respectively. Correlations of serum NEFA, BHB and glucose concentrations with EB were strongest during the transition period. Results suggest that controlling energy intake during the dry period might be advantageous for the energy status of dairy cows after calving, whereas energy restriction in early lactation leads to metabolic stress. Evidence is provided of a clear relationship between EB and the blood metabolites NEFA and BHB, especially in the transition period.     

Lack of effects of an equine chorionic gonadotropin (eCG) administration between days 9 and 15 postpartum on reproductive performance in a Holstein dairy herd

Recently, it has been demonstrated that administration of equine chorionic gonadotropin (eCG) in the postpartum period in dairy cows can enhance follicle growth, reduce the interval from calving to first ovulation and increase plasma estradiol concentrations, and, thus, could enhance reproductive performance in a dairy herd when administered on day 6 postpartum. The aim of this study was to investigate the effects of a single dose of eCG between days 9 and 15 postpartum on parameters of reproductive performance in dairy cows. German Holstein cows (n = 1937; primiparous cows: n = 748; pluriparous cows: n = 1189) in a commercial dairy farm were randomly assigned to three experimental groups. Animals within the group eCG received a single dose of 600 IU eCG intramuscularly (i.m.) between days 9 and 15 postpartum followed by an i.m. administration of 500 μg cloprostenol after 14 days. Those of treatment group PG received cloprostenol only between days 23 and 29 postpartum. Cows of the control group remained untreated. Starting on day 49 postpartum, cows were subjected to a Presynch‐Ovsynch protocol and inseminated artificially. The impact of application time (days postpartum) of eCG on the intervals calving to first service and calving to conception was statistically not significant. Outcomes of reproductive performance (i.e. first service conception rate, proportion of pregnant cows until 100 and 150 days in milk [DIM], number of inseminations until 150 DIM, calving to first service interval and calving to conception interval) did not differ significantly between treatment group eCG and group PG compared to control group. Regarding postpartum eCG administration, significant interactions between treatment and parity, season, milk yield, and early puerperal disorders, respectively, could not be shown. In conclusion, an eCG treatment of dairy cows between days 9 and 15 postpartum to increase reproductive performance cannot be recommended under the given circumstances.     

Coxiella burnetii: Serological reactions and bacterial shedding in primiparous dairy cows in an endemically infected herd—impact on milk yield and fertility

Coxiella burnetii (C. burnetii) is the causative agent of Q fever both in humans and animals. The objectives of this study were to investigate seropositivity and bacterial shedding in heifers and primiparous cows in an endemically infected herd and to assess the effects on post‐partum diseases, fertility and milk production. At the age of 9 months, 96 Holstein heifers were included. Sampling was performed reproduction‐orientated: at the beginning of the study, at detection of first pregnancy, 3 weeks before expected calving date (blood serum), at parturition and after 21, 42, 100 and 150 days in milk (DIM) (blood serum, vaginal swabs and milk). Serum samples were investigated by a commercial ELISA for the presence of specific antibodies and vaginal swabs and milk samples by PCR to detect C. burnetii DNA. Individual animal data (calving ease, stillbirth, retained foetal membranes, puerperal metritis, endometritis after 42 DIM, presence of corpus luteum after 42 DIM, interval calving‐first service, interval calving‐conception, number of inseminations until 150 DIM, proportion of pregnant cows until 100 and 150 DIM, proportion of pregnant cows after first service and data of the dairy herd improvement test) were documented. All heifers were seronegative at the age of 9 months and 3 weeks before the expected calving date. Subsequently, the proportion of seropositive animals and the antibody score increased significantly towards 42 and 100 DIM, respectively. Vaginal C. burnetii shedding was highest at parturition (30.9%), while the most positive milk samples were detected after 100 DIM (15.3%). Coxiella burnetii seropositivity and shedding had no impact on parameters of reproduction. However, milk fat yield was declined in puerperal vaginal shedders and cows which seroconverted during their first 42 DIM, respectively.     

Evaluation of biochemical profile of dairy cows with metabolic diseases in tropical conditions

The aims of this study were to characterize the biochemical profile, the reproductive performance and to identify potential predictive biomarkers of disease state of dairy cows with hyperketonemia, lipomobilization and hypocalcemia raised in tropical conditions in southeastern Brazil. Dairy cows (n = 50) were divided into a group of healthy cows (n = 14), cows with lipomobilization (n = 14), cows with hypocalcemia (n = 11), and a group of cows with hyperketonemia (n = 11). Evaluation of body condition score (BCS), body weight (BW) and blood samples was performed on 21, 14, 7, 4 and 2 days before calving, parturition, 1, 7, 14, 21, 30, 45 and 60 days post-partum and milk production was recorded on days 7, 14, 21, 30, 45 and 60 after parturition. Blood samples were assayed for aspartate aminotransferase (AST), gamma-glutammyltransferase (GGT), albumin, total protein, globulin, fibrinogen, total cholesterol, triglyceride, urea and creatinine concentrations. The biochemical profile, BCS, BW, milk production and reproductive performance differed (p < .05) among the groups. Our findings indicate changes in the biochemical profile of dairy cows with metabolic diseases and impaired production and fertility of dairy cows in this group. Variable importance in projection plots demonstrated that cholesterol, urea, total protein, albumin and fibrinogen in the serum were the strongest discriminators between cows with hypocalcemia and healthy cows; and AST, cholesterol, urea and triglycerides for cows with hyperketonemia and healthy cows; and cholesterol, urea, triglycerides, total protein and fibrinogen for lipomobilization and healthy cows, which might be useful as predictive biomarkers of the disease state.     

Acupuncture prevents the postpartum reduction in matrix metalloproteinase type‐2 immunoexpression,tissue concentration and enzyme activity in bovine caruncles

The objectives of this study were to determine the effects of acupuncture in dairy cows (Bos taurus) on caruncular matrix metalloproteinase type‐2 (MMP2) at 0, 2 and 4 hr after calving. Acupuncture (n = 6) was applied at 0 and 2 hr after calving to 6 points that relax the cervix and stimulate uterine contractions. Controls (n = 9) were kept in a stanchion for 15 min without acupuncture. All of the cows in the study delivered their placenta in <4 hr. Formalin‐fixed caruncles were paraffin‐embedded and subjected to routine immunohistochemistry to determine MMP2 expression, which was scored by a single observer. Flash frozen caruncles were homogenized, and protein concentration was determined. MMP2 concentrations were calculated using commercial bovine ELISAs. MMP2 enzyme activity was determined using zymography. The mean value for each time point for each cow was used to calculate the mean ± SEM for each treatment group. MMP2 was predominantly localized to the epithelial and subepithelial stromal cells of the caruncles in both treatment groups. MMP2 immunoexpression was lower 4 hr after calving in the control cows (p = 0.012) but not in the acupuncture treated cows indicating that acupuncture treatment maintained MMP expression. MMP2 tissue concentration was lower 2 hr after calving in the control cows (p = 0.048) but not in the acupuncture treated cows. MMP2 enzyme activity decreased from 0 to 2 hr after calving in control cows (p = 0.046) but not in acupuncture treated cows. This study provides physiologic evidence for the effects of acupuncture on the bovine reproductive tract and substantiates the use of this treatment in cases of placental retention.     

Effect of pre‐ and post‐partum supplementation with lipid‐encapsulated conjugated linoleic acid on milk yield and metabolic status in multiparous high‐producing dairy cows

We evaluated the lactation performance, liver lipid content and plasma metabolites indicating the energy balance of dairy cows supplemented with conjugated linoleic acid (CLA) pre‐ and post‐partum (PP) vs. only PP. A total of 60 cows were divided into three groups (n = 20). Daily diet of cows was supplemented with 14 g of CLA (7 g cis‐9, trans‐11 and 7 g trans‐10, cis‐12 isomers) from week 3 before the expected date of calving (group CLA1), or from the day of calving (group CLA2) until 77–91 days PP. Control cows were fed an isocaloric, isonitrogenous and isolipidic diet without CLA. Between week 3 and week 6 PP, the milk yield of cows in both CLA‐treated groups was approximately 4.5 kg higher (p < 0.05) than in control. Milk fat concentrations decreased from week 3 and were lower in both CLA groups than in control (p < 0.01). Body condition score loss was lower (p < 0.05) in the CLA1 than in the control group on week 5 PP. By week 11 PP, the body condition of both CLA1 and CLA2 groups exceeded that of control. Plasma non‐esterified fatty acid was lower in CLA1 compared to CLA2 and control during the early PP period (p < 0.05), while this difference faded away by the late PP period. Beta‐hydroxybutyrate (BHBA) increased rapidly in all groups following calving. In CLA1 group, it began to decrease sooner than in CLA2 and control. The prevalence of subclinical ketosis (BHBA > 1.2 mm ) was lower in CLA1 group than in CLA2 and control (p < 0.05). Liver biopsy analyses showed that CLA1 treatment decreased (p < 0.05) the total lipid content of liver compared to control at week 5 after calving. Our results show that CLA supplementation is more efficient in alleviating body mass mobilization and decreasing the incidence of subclinical ketosis when applied as early as 3 weeks before calving than started feeding after calving.     

Alterations in biochemical profiles and reproduction performance in postpartum dairy cows with metritis

The aim of the present study was to evaluate the biochemical profile and reproductive performance in postpartum dairy cows with clinical metritis. The research was carried out using performed on 213 pluriparous lactating cows from two dairy herds in southeast Brazil. Dairy cows were assigned into a group of healthy cows (n = 147) and cows with metritis (n = 66). Blood samples to assess serum albumin, cholesterol, fibrinogen, calcium, gamma-glutammyltransferase (GGT), aspartate aminotransferase (AST) and β-hydroxybutyrate (BHBA) concentrations were performed on day 8 ± 2 postpartum. Metritic cows had lower (p < .05) serum albumin, cholesterol and calcium concentration, and higher (p < .05) GGT and AST activity, and BHBA and fibrinogen concentrations when compared to the healthy group. The calving-to-conception interval and services per pregnancy were higher in metritic cows (p < .01) than in healthy cows and the conception rate at first service was lower in metric group (p < .01). Variable importance in projection plots demonstrated that cholesterol was the main discriminator between metritic and healthy cows. Our results indicated alterations in the biochemical profile and impaired reproduction performance in metritic cows.     

β-defensins gene expression in tissues of the crossbred and Tibetan pigs

Delayed resumption of postpartum oestrous cycles in dairy cows is linked to low plasma insulin status and associated changes in ovarian function. Previous studies showed that plasma insulin can be raised by increasing dietary starch concentration, but it is not known if rumen digestible starch and bypass starch would be equally effective. The objective of the two experiments reported here was to investigate whether site of dietary starch digestion influences metabolic hormones and ovarian function. Cows were fed on a standard diet from calving until 40 days postpartum and then fed on treatment diets until 70 days postpartum. In Experiment 1, six cows were transferred to each of five diets with a starch content of 190 g/kg DM, of which 0.40, 0.45, 0.50, 0.55 or 0.60 was bypass starch. In Experiment 2, eight cows were transferred to each of four diets containing concentrates with low (L) or high (H) starch content and predominantly grass (G) or maize (M) silages in a factorial design. Between 60 and 70 days postpartum, plasma insulin was not influenced by site of starch digestion in Experiment 1, but insulin was increased by H (P = 0.020) and M (P = 0.048) in Experiment 2. Dietary bypass starch content negatively influenced plasma glucagon concentration (P = 0.046) and the insulin to glucagon ratio (P = 0.005) in Experiment 1. Growth hormone, insulin-like growth factor-I and leptin did not vary among diets in either experiment. The number of small (< 5 mm) ovarian follicles before ovulation tended (P = 0.056) to decrease with increasing dietary bypass starch content and was negatively related (P = 0.046) to plasma glucagon in Experiment 1, but there was no other dietary effect on ovarian function in either experiment. The main conclusion from these experiments is that rumen digestible starch and rumen bypass starch can be equally effective for maintaining plasma insulin and ovarian function of high-yielding dairy cows in early lactation.     

Inflammatory and metabolic responses to an intramammary lipopolysaccharide challenge in early lactating cows supplemented with conjugated linoleic acid

Supplementation of dairy cows with trans‐10, cis‐12 conjugated linoleic acid (CLA) allows nutrient repartitioning despite an energy deficiency in early lactation, which might be a benefit for the immune system, too. In this study, we investigated potential nutrient sparing effects of CLA in early lactating cows with low plasma glucose concentrations exposed to an intramammary lipopolysaccharide (LPS) challenge. Fifteen multiparous Holstein cows were exposed to an intramammary LPS challenge in week 4 p.p. Eight cows (CLA) were supplemented daily with 70 g of lipid‐encapsulated CLA (6.8 g trans‐10, cis‐12 and 6.6 g of the cis‐9, trans‐11 CLA isomer; CLA) and seven cows with 56 g of control fat (CON). Blood samples were obtained every 30 min along with rectal temperature, heart and respiratory rate, and milk samples were taken hourly until 10 hr after the LPS application. Plasma was analysed for concentrations of glucose, free fatty acids, beta‐hydroxybutyrate (BHB), cortisol, insulin and glucagon. In milk, somatic cell count and activity of lactate dehydrogenase were determined. Initial plasma glucose concentration was lower in CLA than in CON. During the immunostimulation, CLA had higher glucose concentrations than CON, and BHB decreased distinctly in CLA, whereas CON cows maintained BHB concentration at a lower level. Body temperature in CLA increased earlier, the difference between peak and basal temperature was higher, and the decline thereafter occurred earlier. In conclusion, CLA supplementation of early lactating cows exposed to an intramammary LPS challenge affected local and systemic immune responses. We assume that CLA supplementation triggered glycogen storage. Cows supplemented with CLA provided more glucose and preferentially used BHB as an energy source during the immune response. The more intense metabolic and more concentrated endocrine responses support an immunomodulatory effect of CLA supplementation.     

Efficacy of Ozone and Other Treatment Modalities for Retained Placenta in Dairy Cows

Retained placenta is a worldwide recognized clinical condition in puerperal cows, which can significantly affect their health and fertility. Available treatment modalities are often of questionable efficacy or associated with time constraints, practicality or monetary considerations for their wide application in a routine dairy practice. The objective of this study was to compare and assess the efficacy of different treatment options, including a novel ozone treatment, for the retained placenta. Two hundred cows diagnosed with retained placenta were divided into five treatment groups, each receiving a different treatment option. Group A (n = 40) was given a combination treatment of intrauterine ozone and parenteral cephalexin; group B (n = 40) was given intrauterine ozone; group C (n = 40) was given a combination of parenteral cephalexin and intrauterine antibiotic tablets; group D (n = 40) was given only parenteral cephalexin and group E (n = 40) was given parenteral prostaglandins in 11‐day intervals. The control group (group Z, n = 200) included cows that gave birth without assistance and were not diagnosed with a retained placenta. The ozone treatment (groups A and B) was found to be the most effective modality resulting in the shortest period of days open, the smallest number of artificial inseminations until pregnancy, the smallest number of animals diagnosed with fever within 10 days post‐calving, the highest percentage of animals pregnant within 200 days after calving and the smallest number of animals culled because of infertility, when compared to the other treatment groups. The intrauterine ozone flush therefore has a potential as an efficacious and cost‐effective treatment option for retained placenta, with an overall positive effect on puerperal health and fertility in cows.     

Insulin resistance: Relationship between indices during late gestation in dairy cows and effects on newborn metabolism

To investigate the relationship between insulin resistance indices [“Revised quantitative insulin sensitivity check index” (RQUICKI; RQ), “Revised quantitative insulin sensitivity check index ‐ β‐hydroxybutyrate” (RQUICKI_BHB; RQ_BHB), and “Homeostasis model assessment‐insulin resistance” (HOMA‐IR; HR)], and metabolic parameters in dams during late gestation, and their newborn calves. Blood was sampled twice weekly during the experimental period in 30 dry Holstein cows. In calves, blood sampling and body weight measurements were performed immediately after birth, and in 1‐week‐old male calves, liver and muscle biopsy samples were obtained for determining metabolic factor mRNA levels. RQ and RQ_BHB were negatively correlated with insulin, nonesterified fatty acid, BHB, and albumin and were positively correlated with leptin levels in blood during late gestation (p < .05). RQ, rather than RQ_BHB, reflected metabolism of dams, while stronger positive correlations were present between HR and blood insulin concentrations than other parameters, and calves of dams with high HR had low body weight, and high liver and muscle expression of growth hormone and insulin receptor mRNA (p < .05). RQ and HR of dams during late gestation could serve as indicators of dam metabolism and predictors of metabolism in newborn calves respectively.     

Effects of Feeding Dry Glycerol to Primiparous Holstein Dairy Cows on Follicular Development,Reproductive Performance and Metabolic Parameters Related to Fertility during the Early Post‐partum Period

This study examined the effects of dry glycerol supplementation on follicular growth, post‐partum interval to first ovulation, concentration of serum metabolites and hormones related to fertility, body condition score (BCS) and body weight (BW) in primiparous Holstein dairy cows. Sixty primiparous Holstein dairy cows were randomly assigned to two groups (control: n = 30 and glycerol supplemented: n = 30). Dry glycerol (250 g/day/cow) was fed as a top dressing to the common lactating total mixed ration (TMR) from parturition to 21 days post‐partum. Ovaries were examined four times using ultrasonography on days 13, 19, 25 and 36 post‐partum to determine ovarian follicular growth. Concentration of serum metabolites and hormones was determined weekly. Body condition score was evaluated weekly from weeks 1 to 5 after parturition, and BWs were recorded three times on days 1, 11 and 21 during the experimental period. The cows fed dry glycerol had more large follicles (p < 0.0001) and corpora lutea (CL) (p = 0.02) compared with the control cows. Days to the first ovulation (p = 0.06), days to first oestrus (p = 0.05), services per conception (p = 0.06) and days open (p = 0.004) were positively affected by dry glycerol supplementation. Serum concentration of glucose and insulin was higher in dry glycerol‐supplemented cows (p = 0.1; p = 0.06, respectively). Feeding glycerol had no effect on mean serum concentrations of β‐hydroxybutyrate, non‐esterified fatty acids and IGF‐1 during the experimental period. However, significant differences were observed at concentration of BHBA and IGF‐1 (p = 0.02 and p = 0.04, respectively) between two groups on day 21 after calving. The cows in the glycerol‐fed group had higher serum progesterone concentrations on days 33 (p = 0.007) and 36 (p = 0.004) after calving. Supplemented cows had lower body condition loss during weeks 1–5 after calving compared with the control cows (0.34 vs 0.41 BCS). In week 13 post‐partum, the proportion of cycling cows was 83.3 and 69.9% for those which received supplemented or non‐supplemented diet, respectively. These results demonstrated that feeding dry glycerol as a glucogenic supply may be useful to improve negative energy balance and reproductive efficiency in young cows which calve with high requirement of energy.     

Effects of realimentation after nutrient restriction during mid‐ to late gestation on pancreatic digestive enzymes,serum insulin and glucose levels,and insulin‐containing cell cluster morphology

This study examined effects of stage of gestation and nutrient restriction with subsequent realimentation on maternal and foetal bovine pancreatic function. Dietary treatments were assigned on day 30 of pregnancy and included: control (CON; 100% requirements; n = 18) and restricted (R; 60% requirements; n = 30). On day 85, cows were slaughtered (CON, n = 6; R, n = 6), remained on control (CC; n = 12) and restricted (RR; n = 12), or realimented to control (RC; n = 11). On day 140, cows were slaughtered (CC, n = 6; RR, n = 6; RC, n = 5), remained on control (CCC, n = 6; RCC, n = 5) or realimented to control (RRC, n = 6). On day 254, the remaining cows were slaughtered and serum samples were collected from the maternal jugular vein and umbilical cord to determine insulin and glucose concentrations. Pancreases from cows and foetuses were removed, weighed, and subsampled for enzyme and histological analysis. As gestation progressed, maternal pancreatic α‐amylase activity decreased and serum insulin concentrations increased (p ≤ 0.03). Foetal pancreatic trypsin activity increased (p < 0.001) with advancing gestation. Foetal pancreases subjected to realimentation (CCC vs. RCC and RRC) had increased protein and α‐amylase activity at day 254 (p ≤ 0.02), while trypsin (U/g protein; p = 0.02) demonstrated the opposite effect. No treatment effects were observed for maternal or foetal pancreatic insulin‐containing cell clusters. Foetal serum insulin and glucose levels were reduced with advancing gestation (p ≤ 0.03). The largest maternal insulin‐containing cell cluster was not influenced by advancing gestation, while foetal clusters grew throughout (p = 0.01). These effects indicate that maternal digestive enzymes are influenced by nutrient restriction and there is a potential for programming of increased foetal digestive enzyme production resulting from previous maternal nutrient restriction.     

Study on some risk factors and effects of bovine ketosis on dairy cows from the Galicia region (Spain)

The study was designed to determine the relation between β‐hydroxybutyrate (BHB) concentrations in milk from dairy cows after calving and the length of the previous lactation, the dry period and the 305‐day normalized production, and to assess the influence of BHB concentrations on culling and test‐day milk productions and somatic cell counts (SCC) throughout the lactation that followed the BHB measurement. The data used in the study were obtained from 59 187 cows in the Galicia region (Spain). BHB determination was performed using Fourier‐transformed infrared spectrometry from the milk samples collected from each cow on the first post‐partum test day. For statistical analysis, the following methods were applied: (i) ordinal regression to assess the effect of the length of the previous lactation, the dry period and the 305‐day normalized milk production on milk BHB, (ii) a Cox model to estimate the influence of the BHB concentration on risk of culling (overall and for a variety of reasons) and (iii) linear regression to assess the link between BHB and the milk yield and SCC obtained from each of the tests day performed throughout lactation. The probability of having higher BHB concentrations increased when the length of the previous lactation (p = 0.006), the dry period (p = 0.003) and the 305‐day normalized milk yield (p = 0.005) increased. However, the slight increase observed (especially for the case of the dry period and the 305‐day milk yield) would not justify that measures be implemented to reduce these traits. Higher concentrations of BHB led to an increased risk of culling due to ‘death’ (p ≤ 0.001) and ‘urgent slaughter’ (p ≤ 0.002) (both causes of involuntary culling). It also led to a reduction in milk production (p < 0.001) and an increase in SCC (p < 0.001) in the post‐partum; from that moment onward (including peak lactation), there were no differences in those two parameters depending on the BHB levels.     

Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover

Supplementing conjugated linoleic acid ( CLA ) is supposed to spare glucose due to the milk fat‐depressing effect of the trans ‐10, cis ‐12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC ) in weeks ?2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70 g of lipid‐encapsulated CLA (6.8 g trans ‐10, cis ‐12 and 6.6 g of the cis ‐9, trans ‐11 CLA isomer; CLA ; n  = 11) or with 56 g of control fat ( CON ; n  = 11). From week ?3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI ) were recorded daily, while body weight (BW ) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30 min during the HGC . Plasma was analysed for concentrations of glucose, fatty acids (FFA ), beta‐hydroxybutyrate (BHB ), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week ?2 although glucose target concentration achieved during the steady‐state period was similar for all three HGC . Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.     

Neutrophil function and energy status in Holstein cows with uterine health disorders

The objectives of this study were to investigate the associations between peripheral blood neutrophil (PMN) function, energy status, and uterine health in periparturient dairy cows. Data were collected from 83 multiparous Holstein cows. Blood samples for PMN function determination were collected weekly from 1 week prior to calving (week -1) through 4 weeks after calving and again at 8 weeks after calving. Energy metabolites were measured and dry matter intake (DMI) was determined from weeks -2 to 5 to evaluate energy status of cows during the periparturient period. All cows were examined for uterine health disorders. Blood PMN killing ability was evaluated by determining myeloperoxidase activity and cytochrome c reduction activity in isolated blood PMN's. For cows that were diagnosed with puerperal metritis and subclinical (SC) endometritis and puerperal metritis, blood PMN functions were significantly (P<0.05) impaired during the periparturient period, compared to cows with normal uterine health. Cows with subclinical endometritis and puerperal metritis or SC endometritis also had significantly (P<0.01) higher NEFA and significantly (P<0.001) lower DMI during the periparturient period, and significantly (P<0.05) higher BHBA during early lactation, compared to cows with normal uterine health. Neutrophil function was also significantly (P<0.01) impaired in cows with peripartum negative energy balance, which was characterized by elevated blood levels of NEFA and decreased DMI. Decreased PMN function and energy balance were associated with uterine health disorders and the decreases in PMN function and energy balance occurred prior to parturition and prior to the detection of these uterine disorders.