Sire contribution to fertilization failure and early embryo survival in cattle.

Despite passing routine laboratory tests of semen quality, bulls used in artificial insemination (AI) exhibit a significant range in field fertility. The objective of this study was to determine whether subfertility in AI bulls is due to issues of sperm transport to the site of fertilization, fertilization failure, or failure of early embryo or conceptus development. In experiment 1, Holstein-Friesian bulls (3 high fertility, HF, and 3 low fertility, LF) were selected from the national population of AI bulls based on adjusted fertility scores from a minimum of 500 inseminations (HF: +4.37% and LF: -12.7%; mean = 0%). Superovulated beef heifers were blocked based on estimated number of follicles at the time of AI and inseminated with semen from HF or LF bulls (n = 3-4 heifers per bull; total 19 heifers). Following slaughter 7 d later, the number of corpora lutea was counted and the uteri were flushed. Recovered structures (oocytes/embryos) were classified according to developmental stage and stained with 4',6-diamidino-2-phenylindole to assess number of cells and accessory sperm. Overall recovery rate (total structures recovered/total corpora lutea) was 52.6% and was not different between groups. Mean (± standard error of the mean) number of embryos recovered per recipient was 8.7 ± 5.2 and 9.4 ± 5.5 for HF and LF, respectively. Overall fertilization rate of recovered structures was not different between groups. However, more embryos were at advanced stages of development (all blastocyst stages combined), reflected in a greater mean embryo cell number on d 7 for HF versus LF bulls. Number of accessory sperm was greater for embryos derived from HF than for LF bulls. The aim of experiment 2 was to evaluate the effect of sire fertility on survival of bovine embryos to d 15. Day 7 blastocysts were produced in vitro using semen from the same HF (n = 3) and LF (n = 3) bulls and transferred in groups of 5-10 to synchronized heifers (n = 7 heifers per bull; total 42 heifers). Conceptus recovery rate on d 15 was higher in HF (59.4%,) versus LF (45.0%). Mean length of recovered conceptuses for HF bulls was not affected by fertility status. In conclusion, while differences in field fertility among AI sires used in this study were not reflected in fertilization rate, differences in embryo quality were apparent as early as d 7. These differences likely contributed to the higher proportion of conceptuses surviving to d 15 in HF bulls.

The effect of by-product inclusion and concentrate feeding rate on milk production and composition, pasture dry matter intake, and nitrogen excretion of mid-late lactation spring-calving cows grazing a perennial ryegrass-based pasture.

Interest is growing in the use of by-products as economical sources of nutrients that complement grazed grass, particularly at times when grass supply is insufficient to meet the nutritional demands of lactating dairy cattle. The objective of this research was to assess the effect of the amount of by-product inclusion and concentrate feeding rate on pasture dry matter intake, milk production and composition, and N excretion from spring-calving cows grazing summer pasture during mid-late lactation. Forty-eight Holstein Friesian dairy cows were randomly assigned to 1 of 4 dietary treatments in a 2 × 2 factorial design. Cows were grazed in one group on a perennial ryegrass-based sward, with pelleted concentrates offered twice daily during milking over a 63-d experimental period. The dietary treatments were 3 kg of concentrate containing 35% by-products; 6 kg of concentrate containing 35% by-products; 3 kg of concentrate containing 95% by-products; and 6 kg of concentrate containing 95% by-products on a fresh matter basis. The by-products used were soybean hulls, palm kernel expeller, and maize dried distillers grains with solubles, included in equal proportions on a dry matter basis. Pasture dry matter intake (14.5 kg/d) was not affected by the amount of by-product inclusion or feeding rate. By-product inclusion had no effect on milk yield (27.1 kg/d) or milk solids (MS) yield (2.0 kg/d). Cows offered 6 kg of concentrate had a greater milk (+1.6 kg/d) and MS (+0.13 kg/d) yield, consumed more N (+0.08 kg/d), and excreted a lower proportion of N in the milk (0.25 vs. 0.27) and feces (0.39 vs. 0.41) and a higher proportion in the urine (0.39 vs. 0.32) compared with cows offered 3 kg of by-product-based concentrate. In conclusion, by-products can be included at up to 95% of the concentrate fed to cows grazing pasture without affecting pasture dry matter intake, milk production or composition, or N excretion. Cows offered 6 kg of concentrates produced more milk and MS than cows offered 3 kg but had higher urinary N excretion. Economics of this yield response will depend on milk and concentrate prices.

The effect of by-product inclusion level on milk production, nutrient digestibility and excretion, and rumen fermentation parameters in lactating dairy cows offered a pasture-based diet.

The objective of this study was to investigate the effects of replacing barley and soybean meal with increasing levels of by-products on production, digestive, and metabolic parameters in early-mid lactation dairy cows offered perennial ryegrass-based pasture. Forty-eight (32 multiparous and 16 primiparous) dairy cows that were 64 ± 24 d in milk were assigned to 1 of 4 pasture-based dietary treatments (n = 12) in a randomized block design experiment that ran for 70 d. Treatments consisted of a perennial ryegrass-based pasture and 1 of 4 supplementary concentrates: BP35, BP55, BP75, and BP95 containing 35, 55, 75, and 95% by-products, respectively, in the concentrate on a dry matter basis. The by-products used were soyhulls, dried distillers grains, and palm kernel extract in equal proportions. Barley and soybean meal were replaced as by-product inclusion level increased. In this study, intakes of pasture dry matter (15.7 kg) and total dry matter (21.1 kg) were not affected by treatment. Similarly, milk production parameters (milk yield, milk composition, somatic cell count, and urea) were not different between treatments. Unsaturated fatty acids were lower in the milk of cows offered BP35 and BP55 compared with those offered BP75 and BP95. Concentrations of ß-hydroxybutyrate, nonesterified fatty acids, and other blood metabolites were within normal range and did not differ between treatments, and cow body condition score and body weight were also not different. Equally, N was unaffected by diet. Blood urea N was lower in the BP75 group compared with BP35. This study demonstrated that barley and soybean meal can be replaced with soyhulls, dried distillers grains, and palm kernel extract without affecting milk production, digestive, or metabolic parameters in dairy cows offered a pasture-based diet.

Effect of combined exogenous progesterone with luteotrophic support via equine chorionic gonadotrophin (eCG) on corpus luteum development, circulating progesterone concentrations and embryo development in cattle.

The aim was to examine the effect of a single intramuscular (i.m.) injection of equine chorionic gonadotrophin (eCG) on Day 3 after oestrus on corpus luteum (CL) development, circulating progesterone and conceptus development in cross-bred beef heifers. In Experiment 1, heifers received: (1) saline, or a single i.m. injection of eCG on Day 3 at (2) 250IU (3) 500IU (4) 750IU or (5) 1000IU. Administration of eCG resulted in increased luteal tissue area and progesterone and oestradiol concentrations compared with controls. In Experiment 2, heifers received (1) a progesterone-releasing intravaginal device (PRID Delta) from Day 3 to 5 or (2) a PRID Delta from Day 3 to 5 plus a single injection of 750IU eCG on Day 3. In vitro-produced blastocysts (n=10 per recipient) were transferred on Day 7 and heifers were slaughtered on Day 14 to assess conceptus development. Administration of eCG reduced the number of short cycles (6.3% vs 31.3%) and increased mean luteal tissue weight (P=0.02). Insertion of a PRID Delta on Day 3 resulted in an elevation (P<0.05) in serum progesterone until removal on Day 5. Administration of eCG at the time of PRID Delta insertion resulted in higher progesterone levels (P<0.05) from Day 10 onwards. Conceptus dimensions were not affected. In conclusion, a single injection of eCG on Day 3 increased CL size and progesterone concentrations and, when given in conjunction with a progesterone-releasing device, appeared to reduce the number of short cycles, presumably due to its luteotrophic nature. The implications of the elevated oestradiol concentrations for embryo quality require further study.

Effect of hCG administration during corpus luteum establishment on subsequent corpus luteum development and circulating progesterone concentrations in beef heifers.

This study examined the effect of a single administration of human chorionic gonadotrophin (hCG) on Day 1 to 4 after oestrus on corpus luteum (CL) development and circulating progesterone (P4). Oestrus-synchronized heifers (n=43) were administered a single intramuscular injection of saline on Day 1 (control) or 3000IU hCG on Day 1, 2, 3 or 4 after oestrus. Administration of hCG on Day 1 had no effect on CL area, on Day 2 increased CL area from Day 6 to 12 (P<0.05), on Day 3 increased CL area from Day 9 to 11, while on Day 4 increased CL size on Days 9 and 10 (P<0.05). Administration of hCG on Day 4 induced the formation of an accessory CL in 89% of heifers, resulting in a significant increase in total luteal tissue area on the ovaries compared with all other groups. Consistent with the effects on the CL, hCG on Day 1 did not affect P4 concentrations, on Day 2 significantly increased P4 compared with the control from Day 6 to 11 (P<0.05), on Day 3 resulted in a non-significant increase in P4 while hCG on Day 4 increased P4 from Day 8 to 13 compared with the control (P<0.05). In conclusion, administration of hCG as early as Day 2 after oestrus results in increased P4 in circulation from Day 6, which should have beneficial downstream effects in terms of uterine receptivity and conceptus elongation.

Paradoxical effect of supplementary progesterone between Day 3 and Day 7 on corpus luteum function and conceptus development in cattle.

The aim of the present study was to investigate the effect of short-term progesterone (P4) supplementation during the early metoestrous period on circulating P4 concentrations and conceptus development in cattle. The oestrous cycles of cross-bred beef heifers were synchronised using a 7-day P4-releasing intravaginal device (PRID® Delta; 1.55 g P4) treatment with administration of a prostaglandin F(2α) analogue (Enzaprost; CEVA Sante Animale) the day before PRID® Delta removal. Only those heifers recorded in standing oestrus (Day 0) were used. In Experiment 1, heifers were randomly assigned to one of five groups: (1) control: no treatment; (2) placebo: insertion of a blank device (no P4) from Day 3 to Day 7; (3) insertion of a PRID® Delta from Day 3 to Day 7; (4) insertion of a PRID® Delta from Day 3 to Day 5; or (5) insertion of a PRID® Delta from Day 5 to Day 7. In vitro-produced blastocysts were transferred to each heifer in Groups 2-5 on Day 7 (n=10 blastocysts per heifer) and conceptuses were recovered when heifers were killed on Day 14. Based on the outcome of Experiment 1, in Experiment 2 heifers were artificially inseminated at oestrus and randomly assigned to one of three treatment groups: (1) placebo; (2) PRID from Day 3 to Day 5; or (3) PRID from Day 3 to Day 7. All heifers were killed on Day 16 and recovered conceptuses were incubated in synthetic oviducal fluid medium for 24 h; spent media and uterine flushes were analysed for interferon-τ (IFNT). In both experiments, daily blood samples were taken to determined serum P4 concentrations. Data were analysed using the PROC MIXED procedure of SAS (SAS Institute, Cary, NC, USA). Insertion of a PRID resulted in an increase (P<0.05) in serum P4 that declined following removal. In Experiment 1, P4 supplementation from Day 3 to Day 5 (17.0±1.4 mm) or Day 3 to Day 7 (11.3±2.3 mm) increased conceptus length compared with placebo (2.1±1.8 mm). Serum P4 was significantly lower from Day 9 to Day 14 (P<0.05) and the weight of the Day 14 corpus luteum (CL) was lower in the PRID Day 3-7 group than the placebo or control groups. In Experiment 2, supplementation from Day 3 to Day 5 (94.0±18.8 mm) or Day 3 to Day 7 (143.6±20.6 mm) increased conceptus length on Day 16 compared with placebo (50.3±17.4 mm). Serum P4 was significantly lower in the two supplemented groups following PRID removal compared with placebo (P<0.05) and was associated with a lower CL weight in the Day 3-7 group. Conceptus length was strongly correlated with the IFNT concentration in the uterine flush (r=0.58; P=0.011) and spent culture medium (r=0.68; P<0.002). The findings of the present study highlight the somewhat paradoxical effects of P4 supplementation when given in the early metoestrous period in terms of its positive effect on conceptus development and its potentially negative effects on CL lifespan.

Early pregnancy diagnosis on days 18 to 21 postinsemination using high-resolution imaging in lactating dairy cows.

The aim was to assess the ability of corpus luteum (CL) and uterine ultrasound characteristics on d 18 to 21 to predict pregnancy status in lactating dairy cows. Ultrasound examinations were carried out on cows (n = 164) on d 18 to 21 following artificial insemination (AI). Images of the uterus and CL were captured using a Voluson i ultrasound device (General Electric Healthcare Systems, Vienna, Austria) equipped with a 12-MHz, multi frequency, linear array probe. Serum concentrations of progesterone were determined from blood samples collected at each ultrasound examination. Images of the CL were captured and stored for calculation of CL tissue area and echotexture. Images of the CL and associated blood flow area were captured and stored for analysis of luteal blood flow ratio. Longitudinal B-mode images of the uterine horns were stored for analysis of echotexture. Diagnosis of pregnancy was made at each ultrasound examination based on CL blood flow, CL size, and uterine echotexture. Pregnancy was confirmed by ultrasonography on d 30 after AI. The relationship between ultrasound measures and pregnancy outcome, as well as the accuracy of the pregnancy diagnosis made at each ultrasound examination was assessed. Progesterone concentrations and CL tissue area were greater in pregnant compared with nonpregnant cows on all days. The CL blood flow ratio was higher in pregnant compared with nonpregnant cows on d 20 and 21 after AI. Echotexture measures of the CL and uterus were not different between pregnant and nonpregnant cows on any day of examination. The best logistic regression model to predict pregnancy included scores for CL blood flow, CL size, and uterine echotexture on d 21 following AI. Accuracy of pregnancy diagnosis was highest on d 21, with sensitivity and specificity being 97.6 and 97.5%, respectively. Uterine echotexture scores were similar for pregnant and nonpregnant cows from d 18 to 20. On d 21, pregnant cows had higher uterine echotexture scores compared with nonpregnant cows. The logistic regression equation most likely to provide a correct pregnancy diagnosis in lactating dairy cows included the visual score for CL blood flow, CL size, and uterine echotexture on d 21 after AI. In support of this finding, the diagnostic accuracy for visual scores of CL blood flow, CL size, and uterine echotexture were also highest on d 21.

The effect of lactation on post-partum uterine involution in Holstein dairy cows.

The objective was to examine the effect of lactation on uterine involution in post-partum dairy cows. Holstein primiparous cows were used (n = 19, mean age: 3.9 ± 0.1 years). At calving, cows were randomly assigned to one of two treatment groups, lactating (n = 11) or non-lactating (i.e. dried off at calving, n = 8). Examination of the reproductive tract was carried out by ultrasonography twice weekly until week 7 post-partum. Blood samples were collected twice weekly for the analysis of progesterone to indicate the resumption of cyclicity and metabolites indicative of energy status. Uterine involution was assessed in terms of size of the uterine horns, uterine body diameter and uterine fluid volume as assessed by the amount of non-echogenic material measured by ultrasound and position of the uterus. Vaginal mucous score was taken on day 28 post-partum for the assessment of uterine inflammation. Resumption of cyclicity (serum progesterone > 1 ng/ml) had occurred in both groups on average by day 21 post-partum. Concentrations of non-esterified fatty acids and beta-hydroxybutyrate were higher, whereas concentrations of glucose, insulin and IGF-1 were lower (p < 0.05) in lactating compared to non-lactating cows. Lactating cows had a smaller mean uterine body diameter (p < 0.05) than non-lactating cows from days 28 to 42 post-partum (day 28: 20.2 ± 1.3 vs 24.9 ± 1.5 mm, respectively) and had a lower mean uterine fluid volume up to day 49 (p < 0.05). By day 49, there was no difference in uterine diameter (15.2 ± 1.8 vs 15.2 ± 1.6 mm) or uterine fluid volume (0.11 ± 0.38 vs 0.18 ± 0.46) between lactating and non-lactating cows, respectively. Vaginal mucous score revealed no evidence of uterine inflammation in either group. In conclusion, while lactation induced significant alterations in metabolic status, it did not have a major effect on the rate of uterine involution as defined in this study.

Evidence for an early endometrial response to pregnancy in cattle: both dependent upon and independent of interferon tau.

The aims of this study were to 1) identify the earliest transcriptional response of the bovine endometrium to the presence of the conceptus (using RNAseq), 2) investigate if these genes are regulated by interferon tau (IFNT) in vivo, and 3) determine if they are predictive of the pregnancy status of postpartum dairy cows. RNAseq identified 459 differentially expressed genes (DEGs) between pregnant and cyclic endometria on day 16. Quantitative real-time PCR analysis of selected genes revealed PARP12, ZNFX1, HERC6, IFI16, RNF213, and DDX58 expression increased in pregnant compared with cyclic endometria on day 16 and were directly upregulated by intrauterine infusion of IFNT in vivo for 2 h (P < 0.05). On day 13 following estrous endometrial expression of nine genes increased [ARHGAP1, MGC127874, LIMS2, TBC1D1, FBXL7, C25H16orf71, LOC507810, ZSWIM4, and one novel gene (ENSBTAT00000050193)] and seven genes decreased (SERBP1, SRGAP2, AL7A1, TBK1, F2RL2, MGC128929, and WBSCR17; P < 0.05) in pregnant compared with cyclic heifers. Of these DEGs, significant differences in expression between pregnant and cyclic endometria were maintained on day 16 for F2RL2, LIMS2, LOC507810, MGC127874, TBC1D1, WBSCR17, and ZSWIM4 (P < 0.05) both their expression was not directly regulated by IFNT in vivo. Analysis of the expression of selected interferon-stimulated genes in blood samples from postpartum dairy cows revealed a significant increase (P < 0.05) in expression of ZXFX1, PARP12, SAMD9, and HERC6 on day 18 following artificial insemination in cows subsequently confirmed pregnant compared with cyclic controls. In conclusion, RNAseq identified a number of novel pregnancy-associated genes in the endometrium of cattle during early pregnancy that are not regulated by IFNT in vivo. In addition, a number of genes that are directly regulated by short term exposure to IFNT in vivo are differentially expressed on day 18 following estrus detection in the blood of postpartum dairy cows depending on their pregnancy status.

Effect of follicular aspiration just before ovulation on corpus luteum characteristics, circulating progesterone concentrations and uterine receptivity in single-ovulating and superstimulated heifers.

The aim of this study was to investigate, in unstimulated and superstimulated heifers, the effect of follicle aspiration just before ovulation on corpus luteum (CL) development, circulating progesterone (P(4)) concentrations and the ability of the uterus to support embryo development. Following follicle aspiration or ovulation timed from GNRH administration, CL development was assessed by daily ultrasonography, and CL function was assessed in terms of the capacity to produce P(4) and the expression of genes involved in steroidogenesis in luteal tissue. The capacity of the uterine environment to support conceptus development was assessed following transfer and recovery of in vitro-produced embryos. Follicular aspiration just before the expected time of ovulation leads to a significant reduction in CL diameter, CL area and area of luteal tissue. This was associated with a decrease in circulating P(4) in both unstimulated and superstimulated heifers. Follicle aspiration leads to a reduction in conceptus length and area on day 14 in unstimulated heifers only. Follicle aspiration leads to a reduction in the expression of LHCGR in luteal tissue from unstimulated heifers compared with those in which the CL formed after ovulation. Superstimulation significantly reduced the expression of STAR in luteal tissue in both ovulated and follicle-aspirated heifers. In conclusion, in stimulated and unstimulated heifers, aspiration of the preovulatory dominant follicle(s) just before expected ovulation interferes with the subsequent formation and function of the CL, in terms of size and P(4) output and this, in turn, is associated with a reduced capacity of the uterus to support conceptus elongation in unstimulated heifers.

Effects of human chorionic gonadotrophin administration on day 5 after oestrus on corpus luteum characteristics, circulating progesterone and conceptus elongation in cattle.

The aim of the present study was to test the hypothesis that elevated concentrations of progesterone (P4) resulting from the induction of an accessory corpus luteum (CL) by human chorionic gonadotrophin (hCG) administration on day 5 after oestrus would lead to advanced conceptus elongation on day 14 following embryo transfer on day 7. The oestrous cycles of cross-bred beef heifers were synchronised and animals were randomly assigned to receive either of two treatments: (1) intramuscular injection of 3000 IU hCG on day 5 after oestrus (n=14); or (2) intramuscular injection of saline on day 5 after oestrus (n=13). Ovaries were scanned daily by transrectal ultrasonography to assess CL development. Serum concentrations of P4 were determined from daily blood samples collected from the jugular vein. In vitro-produced bovine blastocysts were transferred to synchronised recipients on day 7 after oestrus (n=15 blastocysts per recipient). Heifers were killed on day 14 after oestrus and the uterus was flushed to recover the embryos. Injection of hCG on day 5 induced ovulation of the dominant follicle in all treated heifers and increased the total area of luteal tissue on the ovary, which was associated with a significant increase (P<0.001) in serum concentrations of P4 from day 7 to day 14. Positive associations were detected between circulating P4 with CL area (within-day correlations ranging from r=0.45 to r=0.67) and total area of luteal tissue (within-day correlations ranging from r=0.65 to r=0.86) Administration of hCG did not affect the proportion of day 14 conceptuses recovered. However, compared with the control group, hCG-treated heifers had increased conceptus length (3.91±1.23 vs. 5.57±1.02 mm, respectively; P=0.06), width (1.00±0.06 vs. 1.45±0.05 mm, respectively; P=0.002) and area (5.71±0.97 vs. 8.31±0.83, respectively; P=0.02). Although numerically greater, mean interferon-τ (IFNT) production in vitro did not differ significantly (P=0.54) between embryos recovered from hCG-treated and control heifers. In contrast, there was a strong positive correlation between individual embryo length (r=0.76; P<0.001) and individual embryo area (r=0.72; P<0.001) and IFNT production. In conclusion, administration of hCG on day 5 after oestrus resulted in the formation of an accessory CL and hypertrophy of the original CL, the result of which was an increase in P4 concentrations from day 7 onwards. These elevated P4 concentrations were associated with an increased conceptus area. Furthermore, conceptus size was highly correlated with IFNT secretion in vitro.

The association between metabolic parameters and oocyte quality early and late postpartum in Holstein dairy cows.

The objective of this was to study the association between metabolic parameters and oocyte quality in postpartum lactating dairy cows as assessed by oocyte morphology and development after fertilization and culture in vitro. Holstein-Friesian spring-calving cows were used (n = 16, parity 3.0 ± 0.36, weight at calving 611 ± 16.2 kg, previous 305-d milk yield 6,454.0 ± 276.4 kg). Bodyweight (BW) and body condition score were recorded at approximately 2 wk before expected calving date, at calving, and then weekly until the end of the experiment (approximately 80 d postpartum). Blood plasma samples were collected weekly, starting 2 wk before the expected calving date and continuing until the end of the experiment and were analyzed for nonesterified fatty acids (NEFA), ß-hydroxybutyrate (BHBA), insulin, insulin-like growth factor-I, and glucose. Transvaginal oocyte recovery was carried out twice weekly on each cow for a period of approximately 12 wk starting 14 d after calving until approximately 80 d postpartum. A linear decrease in BW was observed from calving (d 0) to d 28, after which it remained stable. Body condition score decreased from 14 d precalving, reaching a nadir at approximately d 35 to 42, after which it increased to the end of the period. Nonesterified fatty acid concentrations were significantly elevated from the week before calving until d 42 postcalving, whereas BHBA concentration was significantly elevated from calving to d 49 postcalving. Insulin-like growth factor-I concentration dramatically decreased from d -14 to a nadir on d 7. A significant increase in glucose concentration occurred from d -7 to d 0, followed by a precipitous decrease to d 7. Based on the metabolic profiles (particularly NEFA and BHBA concentrations), data from d 0 to 42 postpartum (period 1) were compared with corresponding data from d 42 to 80 (period 2). Apart from body condition score, all of the physiological parameters measured (milk yield, BW, and blood metabolites) differed significantly between the 2 periods. In particular, insulin-like growth factor-I, insulin, and glucose concentrations were higher post-d 42, whereas BHBA and NEFA were lower compared with pre-d 42 postpartum. The number of oocytes recovered per session and oocyte quality grade did not differ between periods. Positive associations of follicles aspirated and insulin, BHBA, and NEFA were detected. The number of oocytes recovered was positively associated with milk yield, BW, and glucose and NEFA concentrations. The number of cleaved oocytes was positively associated with BW and NEFA concentration. In conclusion, the data do not provide evidence of an effect of lactation-induced metabolic stress on oocyte developmental competence in the postpartum dairy cow assessed in terms of morphological quality and ability to develop following in vitro fertilization.

Influence of lactation on metabolic characteristics and embryo development in postpartum Holstein dairy cows.

The aim of this study was to examine the direct effect of lactation on the ability of the reproductive tract of postpartum dairy cows to support early embryo development. Twenty-one primiparous Holstein heifers were used. Immediately after calving, half of the cows were dried off (i.e., never milked), and the other half entered the milking herd and were milked twice daily. Jugular blood samples were taken twice per week from 15 d before calving to approximately 100 d postpartum to measure nonesterified fatty acids, ß-hydroxybutyrate, glucose, insulin, and insulin-like growth factor-I. At the same time, body weight and body condition score were recorded for each cow. At approximately 60 d postpartum (experiment 1), approximately 65 two- to four-cell embryos, produced by in vitro maturation and fertilization, were endoscopically transferred to the oviduct ipsilateral to the corpus luteum of all cows on d 2 of the estrous cycle. Five days later (d 7), the oviduct and uterus were flushed nonsurgically and the number of embryos developing to the blastocyst stage was recorded. At approximately 90 d postpartum (experiment 2), the estrous cycles of the same cows were resynchronized and 15 to 20 in vitro-produced blastocysts were transferred to the uterus of each recipient on d 7. All cows were slaughtered on d 14 to assess embryo survival and dimensions. Body weight and body condition score were significantly different between groups for the entire postpartum period of the study. Concentrations of nonesterified fatty acids and ß-hydroxybutyrate were higher and concentrations of glucose, insulin, and insulin-like growth factor-I were lower in lactating compared with nonlactating cows. Embryo recovery rates from lactating and dry cows were similar. In experiment 1, fewer embryos developed to the blastocyst stage in the lactating cows compared with the nonlactating cows. In experiment 2, embryo survival and conceptus dimensions were not different between lactating and nonlactating cows. In conclusion, the data indicate that the reproductive tract of the lactating dairy cow is compromised in its ability to support early embryo development compared with that of matched dry cows and this may contribute to early embryo mortality observed in such animals.

Enhancing early life nutrition alters the hepatic transcriptome of Angus × Holstein-Friesian heifer calves.

Early life nutrition has a major influence on subsequent lifetime performance in cattle. The aim of this experiment was to investigate the effect of plane of nutrition from 3 to 21 weeks of age on the liver transcriptome. Holstein-Friesian × Angus heifer calves with a mean (±SD) age and BW of 19 (±5) days and 51.2 (±7.8) kg, respectively, were assigned to either a high-energy diet to support a mean average daily gain (ADG) of 1.2 kg/day (HI; n = 15) or a moderate diet (MOD; n = 15) to support a mean ADG of 0.5 kg/day. At 145 ±â€¯3 days of age, all calves were euthanised, liver tissue samples collected and flash-frozen in liquid nitrogen. Following RNA sequence analysis, the total number of differentially expressed genes (DEGs) (at false discovery rate (FDR) > 0.05) was 537; 308 upregulated and 229 downregulated in HI compared to MOD. The number of DEGs mapped to IPA (at FDR > 0.05) was 460; 264 upregulated and 196 downregulated. There was greater expression of genes associated with cellular development and metabolism in heifers on the HI compared to the MOD diet. The genes (fold change) of the somatotrophic axis; IGF1 (3.7), IGFALS (2.6) and GHR (1.5) were upregulated in the HI compared to MOD diet. The cytokine receptor genes, IL17RB (1.7) and IL20RA (3.3), were upregulated in the HI heifers, which were detected in a network interacting with metabolically regulated genes. The potential enhanced cell-to-cell communication evident from DEGs would increase the calves' ability to combat health challenges. The findings of this study indicate that enhancing the early life plane of nutrition in heifer calves results in the upregulation of genes that are associated with increased metabolic activity and thus metabolic capacity. Moreover, the interaction between metabolic and immune communication genes indicates that enhanced nutrition has the potential to improve the immune response in the liver which will play a central role in ensuring optimal lifetime performance.

High concordance of bovine single nucleotide polymorphism genotypes generated using two independent genotyping strategies.

Single nucleotide polymorphisms (SNPs) represent the most common form of DNA sequence variation in mammalian livestock genomes. While the past decade has witnessed major advances in SNP genotyping technologies, genotyping errors caused, in part, by the biochemistry underlying the genotyping platform used, can occur. These errors can distort project results and conclusions and can result in incorrect decisions in animal management and breeding programs; hence, SNP genotype calls must be accurate and reliable. In this study, 263 Bos spp. samples were genotyped commercially for a total of 16 SNPs. Of the total possible 4,208 SNP genotypes, 4,179 SNP genotypes were generated, yielding a genotype call rate of 99.31% (standard deviation ± 0.93%). Between 110 and 263 samples were subsequently re-genotyped by us for all 16 markers using a custom-designed SNP genotyping platform, and of the possible 3,819 genotypes a total of 3,768 genotypes were generated (98.70% genotype call rate, SD ± 1.89%). A total of 3,744 duplicate genotypes were generated for both genotyping platforms, and comparison of the genotype calls for both methods revealed 3,741 concordant SNP genotype call rates (99.92% SNP genotype concordance rate). These data indicate that both genotyping methods used can provide livestock geneticists with reliable, reproducible SNP genotypic data for in-depth statistical analysis.

The effect of body condition score at calving and supplementation with Saccharomyces cerevisiae on milk production, metabolic status, and rumen fermentation of dairy cows in early lactation.

The objective of this study was to examine the effects of live yeast (LY) supplementation and body condition score (BCS, 1-5 scale) at calving on milk production, metabolic status, and rumen physiology of postpartum (PP) dairy cows. Forty Holstein-Friesian dairy cows were randomly allocated to a 2 × 2 factorial design and blocked by yield, parity, BCS, and predicted calving date. Treatments were body condition at calving (low for BCS ≤3.5 or high for BCS ≥3.75; n=20) and supplementation with LY (2.5 and 10 g of LY/d per cow for pre- and postcalving, respectively; control, no LY supplementation; n=20). The supplement contained 10(9) cfu of Saccharomyces cerevisiae/g (Yea-Sacc(1026) TS, Alltech Inc., Nashville, TN). Daily milk yield, dry matter intake, milk composition, BCS, body weight, and backfat thickness were recorded. Blood samples were harvested for metabolite analysis on d 1, 5, 15, 25, and 35 PP. Liver samples were harvested by biopsy for triacylglycerol (TAG) and glycogen analysis on d 7 precalving, and on d 7 and 21 PP. Rumen fluid was sampled by rumenocentesis for all cows on d 7 and 21 PP. Supplementation with LY had no effect on milk yield, dry matter intake, rumen fluid pH, or blood metabolites concentration of dairy cows with high or low BCS at calving. Feeding LY increased rumen acetate proportion and protozoal population, tended to increase liver glycogen, and decreased rumen ammonia nitrogen during early lactation. Over-conditioned cows at calving had greater body reserve mobilization and milk production and lower feed intake, whereas cows with a moderate BCS at calving had greater feed intake, lower concentrations of nonesterified fatty acids and ß-hydroxybutyrate, lower liver TAG and TAG:glycogen ratio, and faster recovery from body condition loss. Additionally, the data suggest that concentrations of liver enzymes in blood might be used as an indicator for liver TAG:glycogen ratio. Results indicate that in the case of this experiment, where the control treatment was associated with an acceptable rumen pH, feeding yeast did not significantly improve indicators of energy status in dairy cows.

Age at puberty and pregnancy rate in beef heifer genotypes with contrasting nutritional intake from 8 to 13 months of age.

The aim of this study was to examine the effect of plane of nutrition between 8 and 13 months of age on reproductive performance of heifers of early (EM; n = 154) or late (LM; n = 155) maturing beef breeds and with dairy (dairy-bred, n = 154) or beef (beef-bred, n = 155) dams. Heifers were fed to have an average daily gain (ADG) of 0.50 kg (MOD) or >1.00 kg (HI) for a 141- and 150-day indoor winter period. Subsequently, heifers grazed pasture, and a 12 week breeding programme was implemented. Compared to heifers fed the MOD intake diet, heifers fed the HI intake diet were younger (P < 0.001) and had greater bodyweights (P < 0.001) at puberty but did not have a greater 6- (P =  0.41) or 12- (P =  0.32) week pregnancy rate. Dairy-bred heifers were of a similar age (P = 0.55) but had a lesser bodyweight (P <  0.001) at puberty and had a greater 6- (P <  0.05) and 12- (P < 0.01) week pregnancy rate compared to beef-bred heifers. Compared to LM heifers, EM heifers were younger (P < 0.001), had a lesser bodyweight (P < 0.01) at puberty and had a greater 6-week (P < 0.01) but not 12-week (P =  0.96) pregnancy rate. Enhanced nutrition resulted in a younger age at puberty but had no effect on 12-week pregnancy rate. Dam but not sire breed affected 12-week pregnancy rate.

Effect of dietary n-3 polyunsaturated fatty acid supplementation and post-insemination plane of nutrition on systemic concentrations of metabolic analytes, progesterone, hepatic gene expression and embryo development and survival in beef heifers.

Nutrition, and particularly dietary energy intake, plays a fundamental role in reproductive function in cattle. There is some evidence that supplemental omega-3 dietary polyunsaturated fatty acids (n-3 PUFA) can exert positive effects on fertility. The objectives of this study were to evaluate the effect of dietary n-3 PUFA supplementation, post-insemination energy plane of nutrition and their interaction on embryo survival in cattle. Crossbred beef heifers (n = 185) were individually offered barley straw ad libitum and 6 kg DM of concentrate supplemented with either a rumen-protected source of saturated fatty acid (palmitic; control, CON) or a partially rumen-protected n-3 PUFA-enriched supplement (n-3 PUFA). Estrous was synchronised using two injections of PG administered at 11-d intervals and following artificial insemination (AI = Day 0) 179 heifers exhibiting oestrus were inseminated and assigned to one of two dietary treatments: (i) remain on their pre-insemination high dietary plane of nutrition (High) or (ii) restricted to 0.6 × estimated maintenance energy requirements (Low) in a 2 × 2 factorial design. The heifers were then maintained on their assigned diets until slaughter and embryo recovery on Day 16 (n = 92) or pregnancy diagnosis by ultrasound scanning at Day 30 post-AI (n = 87). Plasma concentrations of fatty acids, metabolites, insulin, progesterone (P4) and insulin-like growth factor 1 (IGF-1) were measured at appropriate intervals. Hepatic expression of mRNA for aldo-keto reductase (AKR1C), cytochrome P450 2C (CYP 2C) and cytochrome P450 3A (CYP 3A) was examined. The n-3 PUFA supplementation increased plasma n-3 PUFA concentration (P < 0.05) and reduced n-6: n-3 PUFA ratio (P < 0.05). Plasma IGF-1 was higher for n-3 PUFA relative to the CON (P < 0.05) and for High compared with Low plane of nutrition post-AI (P < 0.05) groups. A low plane of nutrition post-AI increased plasma concentrations of progesterone from Days 7-16 after insemination (P < 0.001) but reduced embryo length (P < 0.001). Supplementation with n-3 PUFA reduced and tended to reduce hepatic expression of CYP2C (P = 0.01) and CYP3A (P = 0.08), respectively. However, while dietary n-3 PUFA supplementation and an abrupt reduction in nutrient status following insemination elevated plasma concentrations of n-3 PUFA and mid and late phase P4, respectively, there was no effect of either PUFA supplementation or post-insemination plane of nutrition on embryo survival.

Health indicators and costs among outpatients according to physical activity level and obesity.

OBJECTIVE: How biochemical variables influence the costs of the Brazilian National Healthcare System, according to body composition and physical activity. METHODS: Participated in this study 168 patients. Biochemical variables were glucose, triglycerides, total cholesterol, high, low, very low density lipoprotein and C-reactive protein (CRP). For the cost analysis the medical records was analyzed. Physical activity was assessed through questionnaire. Body adiposity was assessed by body mass index. Four groups were defined according body adiposity and physical activity. RESULTS: The active obese group had higher values of very low density lipoprotein and triglycerides when compared to the inactive obese. The non-obese inactive group had lower values of non-high density lipoprotein compared to the inactive obese. The non-obese active group presented lower insulin value when compared to the inactive obese. The inactive obese group presented higher values in the CRP when compared to the non-obese active and inactive groups when compared to non-obese and active obese group. There was a positive correlation between insulin, glucose, CRP and drug and total costs. CONCLUSIONS: Biochemical variables were different according to body composition and physical activity. Insulin, glucose and CRP were related to cost in drugs and total costs.

Metabolic Syndrome, Physical Activity, and Medication-Related Expenditures: A Longitudinal Analysis.

BACKGROUND: Metabolic syndrome (MetS) is a combination of risk factors for cardiovascular disease and type 2 diabetes mellitus. The prevalence of MetS worldwide is increasing. There is no study investigating the economic burden of MetS, especially in developing countries, on medication-related expenditure. The aim of this study was to investigate the association of medication-related expenditures with MetS and to explore how physical activity (PA) may influence this association. METHODS: A total of 620 participants, 50 years or older, randomly selected in the city of Bauru, Brazil. Participants were followed from 2010 to 2014, and data on health care expenditure were collected annually. PA questionnaire was applied at baseline, 2 (2012), and 4 (2014) years later. RESULTS: Mean age was 64.7 (95% confidence interval, 64.1-65.3). MetS was associated with higher medication expenditure related to diseases of the circulatory (P <.01) and endocrine (P <.01) systems. MetS explained 17.2% of medication-related expenditures, whereas PA slightly attenuated this association, explaining 1.1% of all health care costs. CONCLUSION: This study demonstrates that MetS has a significant burden on health care expenditures among adults, whereas PA seems to affect this phenomenon significantly, but in low magnitude.