The effect of puerperal uterine disease on histopathologic findings and mRNA expression of proinflammatory cytokines of the endometrium in dairy cows.

The aim of this study was to investigate the effect of puerperal uterine disease on histopathologic findings and gene expression of proinflammatory cytokines in the endometrium of postpuerperal dairy cows; 49 lactating Holstein-Friesian cows were divided into two groups, one without (UD-; n = 29) and one with uterine disease (UD+; n = 21), defined as retained fetal membranes and/or clinical metritis. General clinical examination, vaginoscopy, transrectal palpation, and transrectal B-mode sonography were conducted on days 8, 11, 18, and 25 and then every 10 days until Day 65 (Day 0 = day of calving). The first endometrial sampling (ES1; swab and biopsy) was done during estrus around Day 42 and the second endometrial sampling (ES2) during the estrus after synchronization (cloprostenol between days 55 and 60 and GnRH 2 days later). The prevalence of histopathologic evidence of endometritis, according to the categories used here, and positive bacteriologic cultures was not affected by group (P > 0.05), but cows with uterine disease had a higher prevalence of chronic purulent endometritis (ES1; P = 0.07) and angiosclerosis (ES2; P ≤ 0.05) than healthy cows. Endometrial gene expression of IL1α (ES2), IL1ß (ES2), and TNFα (ES1 and ES2) was higher (P ≤ 0.05) in the UD+ group than in the UD- group. In conclusion, puerperal uterine disease had an effect on histopathologic parameters and on gene expression of proinflammatory cytokines in the endometrium of postpuerperal cows, indicating impaired clearance of uterine inflammation in cows with puerperal uterine disease.

Effect of suppression of postpartum ovulation on endometrial inflammation in dairy cows.

The objective of this study was to investigate the effect of time of first postpartum ovulation on endometrial inflammation in dairy cows with and without uterine disease during the early puerperal period. Transvaginal follicular puncture (FP) was carried out to suppress postpartum ovulation and formation of a CL until Day 42. Fifty-three lactating Holstein Friesian cows were divided into four groups on the basis of presence (UD+) or absence (UD-) of uterine disease, which was defined as retained fetal membranes and/or metritis, and whether FP had (FP+) or had not been (FP-) carried out. This resulted in the following groups: UD-FP- (n = 15), UD-FP+ (n = 13), UD+FP- (n = 13), and UD+FP+ (n = 12). Cloprostenol was given on Days 55 to 60 postpartum, and GnRH was administered 2 days later for synchronization of ovulation. In the FP- groups, endometrial swab and biopsy samples were collected during the second estrus (approximately Day 40) and during the estrus after synchronization. In the FP+ groups, the same samples were collected during the first estrus (approximately Day 49) and during the estrus after synchronization. The prevalence of positive bacteriologic cultures of the endometrium was not affected by FP (P > 0.05). Histologic signs of endometritis were more severe in UD+FP- cows at second sampling than in UD+FP+ cows (P ≤ 0.05). Endometrial expression of IL1α (in UD- after first sampling and in UD+ after second sampling) and IL1ß (in UD- and UD+ after first sampling) was higher (P ≤ 0.05) in FP- cows than in FP+ cows. Regardless of group, cows with histopathologic evidence of endometritis had higher expression (P ≤ 0.05) of IL1α, IL1ß, IL6, and TNFα than cows without endometritis. In conclusion, suppression of early ovulation by transvaginal FP enhances clearance of uterine inflammation in postpartum cows.

Antepartal insulin-like growth factor 1 and insulin-like growth factor binding protein 2 concentrations are indicative of ketosis in dairy cows.

A study involving a small number of cows found that the concentrations of insulin-like growth hormone 1 (IGF1) may be a useful predictor of metabolic disease. Further, IGF1 may provide also a pathophysiological link to metabolic diseases such as ketosis. The objective of the current study was to test whether the low antepartal total IGF1 or IGF1 binding protein (IGFBP) concentrations might predict ketosis under field conditions. Clinical examinations and blood sampling were performed antepartum (262-270 d after artificial insemination) on 377 pluriparous pregnant Holstein Friesian cows. The presence of postpartum diseases were recorded (ketosis, fatty liver, displacement of the abomasum, hypocalcemia, mastitis, retention of fetal membranes, and clinical metritis or endometritis), and the concentrations of IGF1, IGFBP2, IGFBP3, and nonesterified fatty acids were measured. Cows with postpartum clinical ketosis had lower IGF1 concentrations antepartum than healthy cows. The sensitivity of antepartal IGF1 as a marker for postpartum ketosis was 0.87, and the specificity was 0.43; a positive predictive value of 0.91 and a negative predictive value of 0.35 were calculated. The cows with ketosis and retained fetal membranes had lower IGFBP2 concentrations compared with the healthy cows. It can be speculated that lower IGF1 production in the liver during late pregnancy may increase growth hormone secretions and lipolysis, thereby increasing the risk of ketosis. Lower IGFBP2 concentrations may reflect the suppression of IGFBP2 levels through higher growth hormone secretion. In conclusion, compared with nonesterified fatty acids as a predictive parameter, IGF1 and IGFBP2 may represent earlier biomarkers of inadequate metabolic adaptation to the high energy demand required postpartum.

The somatotropic axis during the physiological estrus cycle in dairy heifers--Effect on hepatic expression of GHR and SOCS2.

Pituitary growth hormone (GH) release and hepatic insulin-like growth factor-I (IGF-I) production increase after an injection of 17ß-estradiol (E2) in ovariectomized dairy cattle. However, whether endogenous sexual steroid hormones also influence the hepatic GH receptor (GHR) signaling pathway during a physiological estrus cycle remains unclear. The aim of this study was to analyze the hepatic GHR signaling pathway during the luteal phase and after a period of increased E2 concentrations (after ovulation) as well as in 7 heifers before ovulation. Ovarian ultrasounds were performed daily during repeated physiological cycles (n = 56) of 30 Holstein Friesian heifers to determine ovulation [before ovulation (n = 7, bOv) and after ovulation 24-60 h after the appearance of estrus signs (n = 49, aOv)] and luteal phase (CLP; d 12 ± 1 after ovulation). Blood samples and liver biopsies were obtained, and blood concentrations of E2, P4, insulin-like growth factor (IGF)-I, IGF-II, and GH were measured. In the liver biopsies, we determined mRNA expression of the estrogen receptor α (ERα), GHR, Janus kinase 2 (JAK2), signal transducer and activator of transcription 5B (STAT5B), suppressor of cytokine signaling (SOCS)2 and 3, IGF-I, and IGF-II by quantitative reverse transcription-PCR. The concentration of E2 was higher bOv than aOv and CLP, as expected. The concentrations of IGF-I and GH were higher bOv and aOv compared with CLP. In contrast, concentrations of IGF-II were lower aOv compared with bOv and CLP. The mRNA expression of GHR was higher in liver biopsies obtained bOv compared with aOv and CLP. Notably, the expression of SOCS2 was higher bOv than aOv and in the CLP. Increased hepatic expression of SOCS2 during estrus was detectable when IGF-I concentrations were high; this result might indicate that SOCS2 expression attenuates the GHR signal transduction pathway during the phase of increased pituitary GH release. In conclusion, hepatic GHR and SOCS2 mRNA expression appeared to be promptly and sensitively regulated by increased E2 levels before ovulation of dairy heifers.

Reproductive performance of Lacaune dairy sheep exposed to artificial long days followed by natural photoperiod without and with additional progestagen treatment during the nonbreeding season.

This study compared the reproductive performance of Lacaune dairy ewes exposed to a light program and subsequent male introduction without (n = 36) or with (n = 36) an additional 6-day progestagen treatment during the nonbreeding season. All ewes were exposed to extended day length (16 hours light and 8 hours darkness) for 77 days during winter (December 15 until March 2) followed by increasing natural photoperiod. At the end of the photoperiodic treatment, three blood samples were collected 6 days apart for progesterone (P4) analysis to determine cyclic activity. One half of the ewes were additionally subjected to a 6-day progestagen treatment in combination with PGF2α and eCG at insert withdrawal. Rams fitted with marking harnesses were introduced to females for 45 days and marked ewes recorded. Ewes exposed to the light program only were joined 40 days after the end of photoperiodic treatment, and ewes with additional progestagen treatment were joined 1 day after insert removal (40-44 days after the end of photostimulation). Lambing data were recorded and fertility (percentage of ewes lambing, lambing rate, and litter size) assessed to the first service period and overall. Mean serum P4 concentrations were similarly (P > 0.05) low in both groups (0.4-0.7 ng/mL vs. 0.4-0.6 ng/mL). On the basis of elevated P4 levels (>1 ng/mL), evidence of luteal activity was found in 27.8% of the ewes at the end of the light program. Estrus response was equally high (97.2%) and estrus distribution highly synchronized in progestagen-treated ewes (91.7% within 4 days). In ewes exposed to the light program only, estrous activity was recorded within 4 days (six ewes), from Day 8 to Day 17 (17 ewes) and from Day 19 to Day 25 (12 ewes) after joining. The percentage of ewes that lambed to the first service period was higher (P < 0.05) in ewes exposed to the light program only than that in the group additionally treated with progestagen/PGF2α/eCG (94.4% vs. 69.4%). Overall, the percentage of lambing ewes was similar in both groups (97.2% and 94.4%), and lambing rates (1.4-1.9) and litter sizes (1.9-2.1) were high and not influenced (P > 0.05) by the treatment. In conclusion, this study reports that exposition of Lacaune ewes to artificial long days followed by natural day length and male introduction is highly effective to induce fertile estrous activity during the nonbreeding season and offers a reliable and practical alternative to hormonal manipulation for out-of-season breeding in sheep.

Effects of two different rearing protocols for Holstein bull calves in the first 3 weeks of life on health status, metabolism and subsequent performance.

The aim of this study was to investigate the impact of weight gain of calves within the first 3 weeks of life on health status and subsequent performance. Holstein bull calves were reared either intensively (IR; individual hutches and ad libitum milk feeding for the first 3 weeks of life; n = 24), or according to the established protocol [ER; 4 l milk/day in hutches during week 1 and 720 g/day milk replacer (MR) from day 8 to 21 in a group pen; n = 24]. Water, hay and concentrates were freely available to all calves. From week 4, calves of both groups were housed together in a group pen and fed 720 g MR/day; step-down weaning was performed between week 5 and 10. Key metabolic blood parameters were analysed on day 2, 12, 21 and 70 of life. After weaning, all animals were fed concentrates and corn silage until slaughter at an age of 8 months. Within the first 3 weeks, average daily weight gain was threefold higher in IR calves in relation to ER calves (1.28 vs. 0.38 kg/day, p < 0.001). Neither incidence nor duration of scouring differed significantly between groups. Starter intake (week 4-10) was higher in IR calves in relation to ER calves (49.7 vs. 38.0 kg/calf, p = 0.006). Serum glucose, urea, albumin and insulin were higher at an age of 21 days in IR calves in relation to ER calves; no differences were obvious at an age of 70 days. Plasma GH and IGF-I concentrations revealed an uncoupling of the somatotropic axis in ER calves within the first 3 weeks of life. At slaughter, body weight of IR calves tended to be higher than that of the ER calves (320 vs. 309 kg, p = 0.07). In conclusion, intensive feeding and individual housing during the first 3 weeks of life had positive long-term effects on subsequent performance.

Technical note: The use of a sonomicrometry system for monitoring uterine involution in postpartum dairy cows.

Sonomicrometry allows the measurement of the distance between 2 piezoelectric crystals and has been widely used to investigate the contractility of the heart and gastrointestinal tract. The objective of this study was to determine whether this method can be used to quantify the reduction in uterine size in cows postpartum. Seven healthy pluriparous Holstein Friesian cows (3.7±0.7 yr old, parity 2.4±0.5, mean±SD) were used. Three weeks before calving, 4 piezoelectric crystals were implanted via laparotomy in the myometrium of the greater curvature of the pregnant uterine horn in a longitudinal direction. Sonometric measurements were conducted daily from 2 d before parturition until 14 d after calving, followed by measurements every other day until d 28. Changes in the distance between neighboring crystals were presented as relative changes (%) from baseline values before parturition. The diameter of the previously pregnant uterine horn was measured using transrectal B-mode sonography from d 10 to 28 after calving. The cows were slaughtered 39±6 d postpartum and the uterus was evaluated for fixation of the crystals. The distances between neighboring crystals underwent changes with a reduction of greater than 50% until d 1 postpartum, but no further changes were recorded from d 1 to 7. In the second week, changes in all distances were affected by day postpartum. One distance was affected by day postpartum in wk 3 and 4. There was a positive correlation between the diameter of the previously pregnant horn and the distances between the crystals. Examination of the uterus after slaughter of the cows revealed that 8 crystals (29%) were no longer fixed in the myometrium. Seven of these (25%) could be evaluated completely or partially and 1 (4%) could not be analyzed. Sonomicrometry seems to be suitable for the objective measurement of reduction in uterine length in cows.

Effects of parturition and feed restriction on concentrations and distribution of the insulin-like growth factor-binding proteins in plasma and cerebrospinal fluid of dairy cows.

Hormones and metabolites act as satiety signals in the brain and play an important role in the control of feed intake (FI). These signals can reach the hypothalamus and brainstem, 2 major centers of FI regulation, via the blood stream or the cerebrospinal fluid (CSF). During the early lactation period of high-yielding dairy cows, the increase of FI is often insufficient. Recently, it has been demonstrated that insulin-like growth factors (IGF) may control FI. Thus, we asked in the present study if IGF-binding proteins (IGFBP) are regulated during the periparturient period and in response to feed restriction and therefore might affect FI as well. In addition, we specifically addressed conditional distribution of IGFBP in plasma and CSF. In one experiment, 10 multiparous German Holstein dairy cows were fed ad libitum and samples of CSF and plasma were obtained before morning feeding on d -20, -10, +1, +10, +20, and +40 relative to calving. In a second experiment, 7 cows in second mid-lactation were sampled for CSF and plasma after ad libitum feeding and again after feeding 50% of the previous ad libitum intake for 4 d. Intact IGFBP-2, IGFBP-3, and IGFBP-4 were detected in plasma by quantitative Western ligand blot analysis. In CSF, we were able to predominantly identify intact IGFBP-2 and a specific IGFBP-2 fragment containing detectable binding affinities for biotinylated IGF-II. Whereas plasma concentrations of IGFBP-2 and IGFBP-4 increased during the periparturient period, IGFBP-3 was unaffected over time. In CSF, concentrations of IGFBP-2, both intact and fragmented, were not affected during the periparturient period. Plasma IGF-I continuously decreased until calving but remained at a lower concentration in early lactation than in late pregnancy. Food restriction did not affect concentrations of IGF components present in plasma or CSF. We could show that the IGFBP profiles in plasma and CSF are clearly distinct and that changes in IGFBP in plasma do not simply correspond in the brain. We thus assume independent control of IGFBP distribution between plasma and CSF. Due to the known anorexic effect of IGF-I, elevated plasma concentrations of IGFBP-2 and IGFBP-4 during the postpartum period in conjunction with reduced plasma IGF-I concentrations may be interpreted as an endocrine response against negative energy balance in early lactation in dairy cows.

Immunization against gonadotropin-releasing hormone in dairy cattle: antibody titers, ovarian function, hormonal levels, and reversibility.

Suppression of cyclic activity in cattle is often desired in alpine farming and for feedlot cattle not intended for breeding. A cattle-specific anti-GnRH vaccination (Bopriva, Zoetis Australia Ltd., West Ryde, Australia) is approved for use in heifers and bulls in New Zealand, Australia, Mexico, Brazil, Argentina, Turkey, and Peru. Eleven healthy, cyclic Swiss Fleckvieh cows were included in the study and vaccinated twice with Bopriva 4wk apart. Injection site, rectal body temperature, and heart and respiratory rates were recorded before and 3d following each vaccination. Blood samples were taken weekly for progesterone and estrogen analysis and to determine GnRH antibody titer. Ovaries were examined weekly, using ultrasound to count the number of follicles and identify the presence of a corpus luteum. Thirty weeks after the first vaccination, the cows were subjected to a controlled internal drug-releasing device-based Select-Synch treatment. The GnRH antibody titers increased after the second vaccination and peaked 2wk later. Estrogen levels were not influenced by vaccination, and progesterone level decreased in 7 of 11 cows up to 3wk after the second vaccination and remained low for 10 to 15wk following the second vaccination. The number of class I follicles (diameter ≤5mm) was not influenced by vaccination, whereas the number of class II follicles (diameter 6-9mm) decreased between 7 and 16wk after the first vaccination. Class III follicles (diameter >9mm) were totally absent during this period in most cows. The median period until recurrence of class III follicles was 78d from the day of the second vaccination (95% confidence interval: 60-92d). After vaccination, all cows showed swelling and pain at the injection site, and these reactions subsided within 2wk. Body temperature and heart and respiratory rates increased after the first and second vaccinations and returned to normal values within 2d of each vaccination. The cows in our study were not observed to display estrus behavior until 30wk after the first vaccination. Therefore, a Select-Synch protocol was initiated at that time. Ten cows became pregnant after the first insemination (the remaining cow was reinseminated once until confirmed pregnancy). Bopriva induced a reliable and reversible suppression of reproductive cyclicity for more than 2mo. The best practical predictor for the length of the anestrus period was the absence of class III follicles.

The effect of puerperal uterine disease on uterine involution in cows assessed by Doppler sonography of the uterine arteries.

The objective of this study was to investigate the effects of puerperal uterine disease on uterine blood flow using trans-rectal Doppler sonography. Lactating Holstein Friesian cows (n=44) were divided into two groups based on whether they were healthy (UD-; n=23) or had uterine disease (UD+; n=21) defined as retained fetal membranes and/or metritis. General clinical examination, vaginoscopy, trans-rectal palpation, and trans-rectal B-Mode sonography were conducted on Days 8, 11, 18, 25 and then every 10 days until Day 65 after calving. Doppler sonography of the uterine arteries was conducted on Day 8, during diestrus after the second ovulation (Days 40-60 after calving) and during diestrus before breeding (Days 63-75 after calving). Cows with uterine disease had greater (P<0.05) uterine size as assessed trans-rectally compared with cows of the UD group. Sonographic measurements on Day 11 after parturition revealed a greater (P<0.05) horn diameter in cows of the UD+ than in the UD- group. Both uterine size and uterine horn diameter decreased more earlier following parturition (P<0.05) in cows of the UD- group. Blood flow volume (BFV) was greater and pulsatility index was less on Day 8 after calving in cows of UD+ than UD- group (P<0.05). In cows of the UD-, but not in those of the UD+ group, there was a further reduction in BFV subsequent to Day 45 after calving (P<0.05). The results of this study show that uterine blood flow measures by trans-rectal Doppler sonography are affected by puerperal uterine disease.

[Fertility after treatment with Eazi-breedTM CIDR G for 6 or 12 days outside the breeding season in Lacaune dairy sheep]. / Fruchtbarkeit nach 6- und 12-tägiger Behandlung mit Eazi-breed™ CIDR® G ausserhalb der Zuchtsaison beim Lacaune Milchschaf.

This study compares the fertility after short- and long-term synchronization using a progesterone intravaginal device in Lacaune dairy sheep outside the breeding season. For the experiment 108 Lacaune sheep were treated with Eazi-breed™ CIDR® G intravaginal devices (Pfizer Animal Health, Zürich) for 12 days (Group L, n = 60) or 6 days (Group K, n = 48) in combination with eCG (Group L) or with eCG and 125 µg Cloprostenol (Group K) at device removal. Thereafter the ewes were kept together with rams for 60 days, ewes in estrus were recorded and the fertility was assessed after lambing. Blood progesterone concentration was measured at device application, withdrawal and 14 days later. Results show that neither treatment nor parity had an influence on estrus rate (Group L 91.7 %, Group K 93.8 %, nulli- and pluriparous animals 96.9 % and 90.8 %, respectively). Group L showed a tendency towards a better first cycle lambing rate and a significantly (P < 0.05) higher overall lambing rate compared to sheep of Group K (71.7 % vs. 60.4 % and 83.3 % vs. 72.9 %). Pluriparous ewes had higher (P < 0.05) lambing rates and greater (P < 0.05) numbers of lambs born per synchronized ewe than nulliparous sheep for the first cycle (75.0 % vs. 46.9 % and 1.4 ± 1.0 vs. 0.9 ± 1.1) as well as for the overall service period (92.1 % vs. 46.9 % and 1.7 ± 0.8 vs. 0.9 ± 1.1). Fourteen days after insert withdrawal progesterone concentrations were higher (P < 0.05) in Group L than in Group K (7.7 ± 4.3 vs. 5.6 ± 2.7 ng/mL) and in nulli- compared to pluriparous (9.1 ± 5.6 vs. 5.7 ± 2.1 ng/mL) ewes. In conclusion, the overall lambing rate was higher after long-term compared to short progesterone treatment and nulliparous ewes were less suitable for estrus induction outside the breeding season.

Dans ce travail, on étudie la fertilité chez de brebis de race Lacaune lait après une synchronisation des chaleurs de courte et de longue durée au moyen d'un pessaire intra vaginal à la progestérone. Pour cela, 108 brebis Lacaune lait ont été traitées pendant 12 jours (groupe L, n = 60) ou 6 jours (groupe K, N = 48) avec un pessaire vaginal Eazi-breed™ CIDR® G (Pfizer Animal Health, Zürich) en combinaison avec 500 IE d'eCG (groupe L) respectivement 500 IE d'eCG et 125 µg de Cloprostenol (groupe K) au moment du retrait du pessaire. Par la suite, les brebis ont été détenues pendant 60 jours avec des béliers, les chaleurs ont été relevées ainsi que la fertilité après l'agnelage. Le taux sanguin de progestérone a été mesuré lors de la mise en place et du retrait du pessaire ainsi que 14 jours plus tard. Les résultats montrent que ni le traitement ni le nombre de gestations antérieures n'avaient d'influence sur le taux de chaleurs (groupe L 91.7 %, groupe K 93.8 %, brebis nulli- et pluripares 96.9 % respectivement 90.8 %). Les brebis du groupe L montraient, un taux de mise bas tendentiellement meilleur lors du premier cycle et au total significativement plus haut (P < 0.05) que celles du groupe K (71.7 % par rapport à. 60.4 % et 83.3 % par rapport à 72.9 %). Les pluripares avaient, lors du premier cycle et en général, des taux de mise-bas plus élevés que les nullipares (75.0 % contre 46.9 % respectivement 92.1 % contre 46.9 %, P < 0.05) ainsi qu'un nombre d'agneaux plus élevé par brebis synchronisée (1.4 ± 1.0 contre 0.9 ± 1.1 respectivement 1.7 ± 0.8 contre 0.9 ± 1.1, P < 0.05). Quatorze jours après le retrait du pessaire, les taux de progestérone étaient plus élevés dans le groupe L que dans le groupe K (7.7 ± 4.3 contre 5.6 ± 2.7 ng/mL) aussi bien chez les nulli- que chez les pluripares (9.1 ± 5.6 contre 5.7 ± 2.1 ng/mL). En résumé on constate que le taux de mise-bas était meilleur après un traitement long qu'après un traitement court et que les brebis nullipares étaient moins adaptées à la synchronisation des chaleurs hors de la saison de reproduction.

Effect of postpartum suppression of ovulation on uterine involution in dairy cows.

The objective of this study was to investigate the effect of time of first postpartum ovulation after calving on uterine involution in dairy cows with and without uterine puerperal disease. Transvaginal follicular puncture (FP) of follicles >6 mm suppressed ovulation and development of a CL until Day 42 after calving. Fifty-three lactating Holstein Friesian cows (3.4 ± 1.2 years old, parity 2.5 ± 1.0 [median ± mean absolute deviation]) were divided into groups on the basis of the presence (UD+) or absence (UD-) of uterine disease and whether FP was carried out (FP+) or not (FP-). Uterine disease was defined as the occurrence of retained fetal membranes and/or metritis. This resulted in the following groups: UD-FP- (n = 15), UD-FP+ (n = 13), UD+FP- (n = 13), and UD+FP+ (n = 12). A general examination, vaginoscopy, transrectal palpation, and transrectal B-mode sonography of the reproductive organs were conducted on Days 8, 11, 18, and 25 and then every 10 days until Day 65 after calving. After hormonal synchronization of ovulation (cloprostenol between Days 55 and 60 postpartum and GnRH 2 days later), cows were inseminated in the next spontaneous estrus. On average, the cows ovulated on Day 21.0 ± 6.0 (UD-FP-), 50.0 ± 4.0 (UD-FP+), 16.0 ± 3.0 (UD+FP-), and 48.0 ± 2.0 (UD+FP+) postpartum. Calving-to-conception interval and first-service conception rates were not affected by FP (P > 0.05). Healthy cows with FP had smaller (P < 0.05) uterine horn and cervical diameters assessed sonographically than cows without FP. FP reduced the prevalence of purulent vaginal discharge and uterine size assessed transrectally in UD+ cows (P < 0.05). The results showed that suppression of an early ovulation by transvaginal FP improved uterine involution in cows with and without uterine disease.

Hepatic mRNA expression of acid labile subunit and deiodinase 1 differs between cows selected for high versus low concentrations of insulin-like growth factor 1 in late pregnancy.

The somatotropic axis is a key metabolic pathway during transition from late pregnancy to early lactation in dairy cows. The first objective of this study was to determine the feasibility of selecting cows with persistent differences in total insulin-like growth factor 1 (IGF-1) concentration by taking only a single antepartum blood sample. The second objective was to elucidate the underlying causes of differences in peripheral IGF-1 concentrations throughout late pregnancy and whether hormonal axes also differed in dairy cows with low versus high IGF-1. Twenty clinically healthy Holstein Friesian cows were chosen based on their plasma IGF-1 concentration at 244 to 254 d after artificial insemination (AI) and other selection criteria (health status, body condition score, number of lactations). These cows were selected from a large-scale farm, transported to the clinic, and monitored daily from 261 to 275 d after AI. The concentrations of IGF-1, growth hormone, IGF binding proteins 2, 3, and 4, insulin, cortisol, thyroid hormones, progesterone, and estradiol were measured. Ultimately, 7 IGF-1-low and 7 IGF-1-high cows were statistically analyzed. Additionally, a liver biopsy was taken on d 270 ± 1 after AI for analysis of gene expression of somatotropic family members, liver deiodinase 1, and suppressor of cytokine signaling-2. It was possible to select cows with different IGF-1 concentrations based upon only 1 blood sample collected in late pregnancy. Concentrations of IGF-1 in IGF-1-low versus IGF-1-high animals (n=7 each) remained significantly different between groups from the day of selection of the animals until d 275 after AI. Second, the differences in total plasma IGF-1 concentration between experimental groups may be attributed to differences in hepatic production of acid labile subunit. The ability of IGFBP-3 to bind IGF-1 declined before calving in all cows. Furthermore, in addition to decreased mRNA expression of growth hormone receptor 1A and IGF-1 relative to calving, serum binding capacities for IGF-1 also decreased. Insulin-like growth factor binding protein 4 mRNA expression was higher in cows with low IGF-1 concentrations; this binding protein inhibits IGF-1 action at the tissue level and therefore may reduce IGF-1 bioavailability. Finally, other endocrine end points (e.g., insulin and thyroid hormones) differed between the 2 groups.

Modulation of follistatin and myostatin propeptide by anabolic steroids and gender.

The purpose of this pilot study was to investigate the impact of training, anabolic steroids and endogenous hormones on myostatin-interacting proteins in order to identify manipulations of myostatin signalling. To identify whether analysis of the myostatin interacting proteins follistatin and myostatin propeptide is suitable to detect the abuse of anabolic steroids, their serum concentrations were monitored in untrained males, bodybuilders using anabolic steroids and natural bodybuilders. In addition, we analysed follistatin and myostatin propeptide serum proteins in females during menstrual cycle. Our results showed increased follistatin concentrations in response to anabolic steroids. Furthermore, variations of sex steroid levels during the menstrual cycle had no impact on the expression of follistatin and myostatin propetide. In addition, we identified gender differences in the basal expression of the investigated proteins. In general, follistatin and myostatin propeptide concentrations were relatively stable within the same individual both in males and females. In conclusion, the current findings provide an insight into gender differences in myostatin-interacting proteins and their regulation in response to anabolic steroids and endogenous hormones. Therefore our data provide new aspects for the development of doping prevention strategies.

Effects of a protracted induction of parturition on the incidence of retained placenta and assessment of uterine artery blood flow as a measure of placental maturation in cattle.

The objectives of the present study were to compare the effects of a protracted and a conventional induction of parturition on the incidence of retained placenta, and to evaluate the suitability of transrectal Doppler sonography of the uterine arteries as a noninvasive method for the assessment of placental maturation. Protracted induction of labor (PIP) was precipitated in 13 cows by the administration of 1.3 mg dexamethasone im twice daily between Days 268 and 273 of gestation, and 40 mg dexamethasone im on Day 274 of gestation. For conventional induction of labor (SIP), 10 cows received 40 mg dexamethasone on Day 274 of gestation. A third group was not treated and served as control (SPON; N = 11). Blood flow volume (BFV) and resistance index in the uterine arteries were measured with Doppler sonography once a day from Day 268 of gestation until labor. After each ultrasonographic examination, blood samples for determination of steroid hormones were taken. Incidence of retained placenta was lower (P < 0.05) in group SPON (9%) compared with groups PIP (54%) and SIP (70%). In the last 7 days before parturition uterine BFV and resistance index did not change (P > 0.05) and did not differ between groups SPON, PIP, and SIP (P > 0.05). Resistance index was higher (P < 0.001) in cows with retained placenta compared with cows with released placenta, and BFV did not differ (P > 0.05) between them. Total estrogen concentrations increased by 283% (P < 0.001) in group PIP and by 60% (P < 0.05) in group SPON between Days -7 and -1 before parturition. They stayed constant (P > 0.05) until Day -2 in group SIP, but increased (P < 0.05) after the high dosage of dexamethasone within 1 day by 140%. Total estrogen levels were higher (P < 0.05) in cows with released placenta than in cows with retained placenta. In conclusion, a protracted compared with a short induction of labor results in higher estrogen levels before term, but does not affect incidence of placental retention. Neither alterations in placental maturation nor changes in steroid hormones influenced uterine blood supply. Therefore, Doppler sonography of uterine arteries is unsuitable to investigate the process of placental maturation induced by glucocorticoids in cows. Nevertheless, disturbances in the placental maturation process in cows with retained fetal membranes after parturition can be detected before parturition by a higher uterine blood flow resistance in the uterine arteries.

Effects of dexamethasone-21-isonicotinate on peripheral insulin action in dairy cows 5 days after surgical correction of abomasal displacement.

BACKGROUND: Dexamethasone frequently is used for treatment of ketosis in dairy cows, but its effects are not fully understood. HYPOTHESIS: Dexamethasone treatment affects whole body insulin sensitivity. ANIMALS: Twelve German Holstein cows, 2-4 weeks postpartum, 5 days after omentopexy to correct left abomasal displacement. METHODS: Randomized, blinded, case-control study. Treatment with dexamethasone-21-isonicotinate (DG; 40 µg/kg IM; n = 6) or saline (control group [CG], 15 mL IM, n = 6) on day 0 (d0). Blood samples were obtained before (d0) and after treatment (d1 and d2), and analyzed for glucose, insulin, and nonesterified fatty acid (NEFA) concentrations. Hepatic triglycerides (TAG) were measured in liver samples taken on d0 and d2. Five consecutive hyperinsulinemic-euglycemic clamps (HEC-I-V; insulin dosages: 0.1, 0.5, 2, 5, 10 mU/kg/min, respectively) were performed on d1 and steady state glucose infusion rate (SSGIR), insulin concentration (SSIC), insulin sensitivity index (ISI = SSGIR/SSIC), and plasma NEFA concentration (SSNEFA) were assessed. RESULTS: Compared with CG-cows, DG-cows on d1 had higher plasma glucose (P = .004) and insulin (P < .001) concentrations, decreased SSGIR (HEC-II, P = .002; HEC-IV, P = .033), ISI (HEC-I, P < .015; HEC-II, P = .004), and insulin-stimulated decrease in SSNEFA (HEC-II, P = .006; HEC-III, P = .01; HEC-IV, P = .003; HEC-V, P = .011). Decrease in hepatic TAG content in DG-cows was higher compared with CG-cows (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Dexamethasone decreases whole body insulin sensitivity and affects glucose and lipid metabolism in early lactating dairy cows.

Modulation of intestinal glucose transport in response to reduced nitrogen supply in young goats.

The reduction of dietary protein is a common approach in ruminants to decrease the excretion of N because ruminants are able to recycle N efficiently by the rumino-hepatic circulation. In nonruminant species an impact on other metabolic pathways such as glucose metabolism was observed when dietary protein intake was reduced. However, an impact of dietary N reduction in goats on glucose metabolism especially on intestinal glucose absorption is questionable because ruminants have very efficient endogenous recycling mechanisms. Therefore, the aim of the present study was to characterize the intestinal absorption of glucose in growing goats kept on different N supply under isoenergetic conditions. The different CP concentrations (20, 16, 10, 9, and 7% CP) of the experimental diets were adjusted by adding urea to the rations. Intestinal flux rates of glucose were determined by Ussing chamber experiments. For a more mechanistic approach, the Na(+)-dependent uptake of glucose into intestinal brush-border membrane vesicles (BBMV) and the expression patterns of the Na(+)-dependent glucose transporter SGLT1 and the glucose transporter 2 (GLUT2) were determined. Reduced N intake resulted in a decrease of plasma glucose (P < 0.001) and insulin (P = 0.004) concentrations whereas the intestinal flux rates of glucose were elevated (P < 0.001), which were inhibited by phlorizin. However, the uptake of glucose into intestinal BBMV was not changed whereas the expression of SGLT1 on mRNA (P < 0.05) and protein abundance (P = 0.03) was decreased in response to a reduced N intake. The mRNA expression of GLUT2 was not affected. From these data, it can be concluded that the intestinal absorption of glucose was modulated by changes in dietary N intake. It is suggested that intracellular metabolism or basolateral transport systems or both might be activated during this feeding regimen because the apical located SGLT1 might not be involved. Therefore, an impact of dietary N reduction on glucose metabolism in growing goats occurred as in monogastric animals.

Escherichia coli lipopolysaccharide administration transiently suppresses luteal structure and function in diestrous cows.

The objective was to characterize the effects of Escherichia coli lipopolysaccharide (LPS) endotoxin (given i.v.) on luteal structure and function. Seven nonlactating German Holstein cows, 5.1 ± 0.8 years old (mean ± s.e.m.), were given 10  ml saline on day 10 (ovulation=day 1) of a control estrous cycle. On day 10 of a subsequent cycle, they were given 0.5 µg/kg LPS. Luteal size decreased (from 5.2 to 3.8 cm², P≤0.05) within 24 h after LPS treatment and remained smaller throughout the remainder of the cycle. Luteal blood flow decreased by 34% (P≤0.05) within 3 h after LPS and remained lower for 72 h. Plasma progesterone (P4) concentrations increased (P≤0.05) within the first 3 h after LPS but subsequently declined. Following LPS treatment, plasma prostaglandin (PG) F metabolites concentrations were approximately tenfold higher in LPS-treated compared with control cows (9.2 vs 0.8 ng/ml, P≤0.05) within 30 min, whereas plasma PGE concentrations were nearly double (P≤0.05) at 1 h after LPS. At 12 h after treatment, levels of mRNA encoding Caspase-3 in biopsies of the corpus luteum (CL) were increased (P≤0.05), whereas those encoding StAR were decreased (P≤0.05) in cattle given LPS vs saline. The CASP3 protein was localized in the cytoplasm and/or nuclei of luteal cells, whereas StAR was detected in the cytosol of luteal cells. In the estrous cycle following treatment with either saline or LPS, there were no significant differences between groups on luteal size, plasma P4 concentrations, or gene expression. In conclusion, LPS treatment of diestrus cows transiently suppressed both the structure and function of the CL.

Effect of vaccination against gonadotropin-releasing factor (GnRF) with Bopriva® in the prepubertal bull calf.

The aim of this study was to evaluate the effect of immunization against gonadotropin-releasing factor (GnRF) with Bopriva(®) (Pfizer Animal Health, Parkville, Australia) in prepubertal bull calves. For the study, 6 calves were vaccinated at the age of 3 and 6 weeks with 1 mL Bopriva(®), and 6 animals served as matched controls. Concentrations of GnRF antibodies, testosterone and LH were determined in serum samples out to 30 weeks after the first immunization. Body weight and scrotal circumference were measured for 59 weeks. At slaughter, 65 weeks after the first immunization, the quality of epididymal sperm was evaluated. The results showed that vaccination against GnRF influenced (P<0.05) anti-GnRF titer, LH and testosterone concentrations as well as scrotal circumference. Antibody titers significantly (P<0.05) increased after the booster vaccination and reached peak values 2 weeks later. Compared to control animals, inhibition (P<0.05) of the prepubertal LH secretion was observed in vaccinated calves at weeks 10 and 12-14 after the first vaccination. In vaccinated calves testosterone concentrations decreased after the booster injection to values below 0.5 ng/mL serum and remained for at least 22 weeks at this low level. Animals vaccinated with Bopriva(®) showed a delay in testes growth and smaller scrotal circumference. Puberty occurred at the age between 46 and 55 weeks in vaccinated and between 38 and 52 weeks in control animals and body weight gain was similar in both groups. All vaccinated bulls attained spermatogenic capacity at slaughter when they were 68 weeks old.

Effect of conjugated linoleic acid supplementation on body composition, body fat mobilization, protein accretion, and energy utilization in early lactation dairy cows.

The objective of the study was to investigate the effects of trans-10,cis-12 and cis-9,trans-11 conjugated linoleic acid (CLA) supplementation on body composition, mobilization or accretion of body fat and protein mass, as well as the energy metabolism of dairy cows during the first 105 d in milk (DIM). For this purpose, a comparative slaughter experiment was conducted with 25 primiparous German Holstein cows. The experiment started at 1 DIM with the slaughter of 5 animals of an initial group receiving no CLA supplement. The remaining animals were fed a CLA supplement (n=10) or a stearic acid-based control fat supplement (CON; n=10) from 1 DIM up to slaughter. After 42 DIM, 5 more cows from each treatment (42-CLA and 42-CON) were slaughtered. The remaining 5 cows in each treatment were slaughtered after 105 DIM (105-CLA and 105-CON). The animals of the CLA groups consumed 6.0 g/d of trans-10,cis-12 CLA and 5.7 g/d of cis-9,trans-11 CLA. During the slaughter process, the empty body mass was recorded and partitioned into 9 fractions (meat, bone, offal, hide, mammary gland, retroperitoneal fat, omental fat, mesenteric fat, and s.c. fat). The fractions were analyzed for dry matter, ether extract, crude protein, and ash to calculate the body composition of the empty body mass at the different slaughter times. The principle of the comparative slaughter technique was applied to estimate body fat or protein mobilization and accretion in the viewed periods from 1 DIM until 42 and 105 DIM. The heat production (HP) was calculated by subtracting the energy in milk and energy changes in body mass from the metabolizable energy intake. The body composition was not affected by CLA supplementation. However, the mobilization of body fat mass from 1 until 42 DIM was 24.1 kg in the 42-CON group and 14.3 kg in the 42-CLA group. This resulted in a trend to lower body mass (fat and protein) mobilization of 10.5 kg in the 42-CLA group. Energy mobilization from body mass was 21.2 MJ/d in the 42-CON and 11.5 MJ/d in the 42-CLA group. The HP was unchanged for the 42-CON and 42-CLA group with 123.0 and 116.9 MJ/d, respectively. From 1 until 105 DIM, the protein accretion was 4.3 kg and the daily energy retention in body protein was 1.0 MJ higher for CLA-supplemented cows. The HP was decreased in this period for the 105-CLA group (115.5 MJ/d) as compared with the 105-CON group (125.9 MJ/d). Overall, the trend for a decreased body mass mobilization suggested a protective effect of CLA supplementation against excessive use of body reserves within 42 DIM. Continuous CLA supplementation until 105 DIM increased protein accretion. The effects on body mass mobilization and protein accretion in combination with the decreased HP in the CLA-fed cows suggested a more efficient utilization of metabolizable energy in CLA-supplemented early lactation dairy cows.