Postpartum Interval Research Articles

Evaluating heat detector patch response to determine gonadotropin-releasing hormone use at timed artificial insemination on pregnancy rates in beef cattle

ABSTRACT This study evaluated pregnancy rates in response to heat detector patch activation and the fate of gonadotropin-releasing hormone (GnRH) at timed AI (TAI) in a 7-d Co-Synch-plus-controlled intravaginal drug release (CIDR) protocol in beef cattle. Nulliparous heifers (n = 75) and lactating cows (n = 371) from 3 locations (n = 35, 139, and 198) were stratified by age, BW, BCS, and postpartum interval to a control (CON) or treatment (TREAT) group. All females received GnRH plus a CIDR insert on d 0, prostaglandin F 2α , CIDR removal, and an Estrotect heat-detector patch on d 7. Beginning 54 h (heifers) and 72 h (cows) post-CIDR removal, a patch score (PS) was given (1 = unremoved; 2 = 35 to 65% removed; 3 = > 65% removed or missing). All heifers and cows in the CON, regardless of PS, and TREAT with a PS 1 received GnRH at TAI; all TREAT heifers and cows with a PS 2 and 3 received no GnRH at TAI. No treatment by location interaction (P > 0.10) existed for TAI pregnancy rates; thus, data was pooled across location. Timed AI pregnancy rates were similar (P > 0.05) between the CON and TREAT groups for heifers (43.2 and 50.0%) and cows (62.7 and 59.7%). Pregnancy rates were similar (P = 0.22) among cows with a PS of 2 and 3 in both groups. Using a heat-detector patch to determine if GnRH is needed at TAI may be an option to reduce CIDR-based TAI protocol cost.

Detection of Equid herpesvirus type 2 and 5 DNA in uterine flushings of mares with reproductive disorders

In recent years, there has been increasing evidence of the potential pathogenic significance of equine gammaherpesviruses in the horse. In humans, cattle and mice, gammaherpesviruses have already been associated with uterine infection. The aim of the present study was to investigate the presence of gammaherpesviruses in uterine flushings of mares with reproductive problems and to evaluate if there was a possible statistical association with clinical and laboratory findings in these cases. A total of 80 uterine flushings were collected from 61 mares with different reproductive problems and these were tested for equine herpesviruses (EHV) 1–5 by PCR. In the case of each mare in the study, the age, history of infertility, presence of anatomical defects in the reproductive tract, presence of systemic or local disease at time of sampling, phase in the oestrous cycle, post-partum interval, nature of uterine lavage performed (low versus large volume lavage), cytological and bacteriological examination results from the uterine flushing, and PCR herpesvirus results were recorded. Univariate analysis and multivariable logistic regression models were used to identify possible statistical associations and risk factors. Nine out of 61 mares (14.7%) had EHV-5 DNA in their uterine flushings. Co-infections with EHV-1 and EHV-2 were present in two cases. Of all the variables analyzed, only the cytological examination findings were associated with EHV-5 PCR positive results, both on univariate and multivariable analysis, especially in cases with an inflammation score of 3. It is postulated that presence of EHV-5 infection in the non-pregnant uterus may have a role to play in reproductive dysfunction and have a negative consequence on the pregnant uterus. Additional studies involving both healthy mares and mares with reproductive problems need to be performed, however, to elucidate whatever role equine gammaherpesviruses may play in the reproductive tract. This would be very worthwhile, since reproductive problems can have a significant impact on the equine breeding industry. Gaining a greater understanding of its causes could lead to new approaches for prevention and treatment.

Caracterización fenotípica, productiva y reproductiva de la cabra blanca Criolla del “Filo Mayor” de la Sierra Madre del Sur en el estado de Guerrero

Con el objetivo de hacer una caracterización fenotípica y de determinar parámetros productivos y reproductivos de la cabra blanca Criolla del "Filo Mayor" en la Sierra Madre del Sur, estado de Guerrero, se llevó a cabo el presente estudio en el municipio de Leonardo Bravo a 17º 39´N y 99º 50´O y en el Colegio Superior Agropecuario del Estado de Guerrero (CSAEGRO) ubicado a 14.5 km de Iguala, Gro., a 18º 15´ N y 99º 39´ O. Los colores de pelo predominantes en las cabras fueron el blanco y el bayo o crema (94.8%); la presencia de cuernos fue común en machos y hembras y sólo un 7.4% de éstas no los presentó. Las cabras presentaron ubres esféricas (52.8%) y alargadas (47.2%), mientras que los machos cabríos presentaron testículos lobulares (46.2%) y bipartidos (53.8%). Predominaron cabras con perfil recto y orejas erectas (90.4%). El peso de los machos cabríos adultos fue de 68.0 ± 2.1 kg, con una altura a la cruz de 78.8 ± 3.7 cm y un perímetro torácico de 88.5 ± 1.5 cm. Las cabras adultas presentaron un peso de 43.0 ± 3.2 kg, una altura a la cruz de 68.8 ± 2.7 cm y un perímetro torácico de 80.7 ± 3.4 cm. La tasa de fertilidad e índice de prolificidad fueron de 61.4% y 1.6 ± 0.12 crías por parto, respectivamente, con un 8.7% de abortos. El peso al nacimiento de los cabritos (sin considerar sexo ni tipo de parto) fue de 2.9 ± 0.13 kg; en tanto que el peso a los 100 d de edad fue de 14.3 ± 1.2 kg, con ganancias diarias de peso del nacimiento al destete de 159.0 ± 0.15 g. La producción de leche por día fue de 785.0 ± 35.9 g y la curva de lactancia registró un pico en las semanas 3 y 4 (800 g) para después descender en forma constante hasta la semana 14 (400 g). La duración de la gestación fue de 168.6 ± 2.21 d, con un periodo parto-primer estro de 136.3 ± 30 d. La ocurrencia de ciclos estrales menores a 17 días fue nula, con una alta proporción de ciclos de entre 17 a 25 d (55.2%) y mayores de 25 d (44.8%); asimismo la cabra en estudio presentó alta proporción de celos menores de 36 h (81.0%). Se concluye que el grupo caprino estudiado presenta características fenotípicas y de comportamiento productivo y reproductivo propios, que la diferencian de otros grupos caprinos Criollos de la región y del país, pero que son parecidos a los rasgos informados para uno de sus posibles antecesores, la cabra Celtibérica de España.

Application of liquid semen technology improves conception rate of sex-sorted semen in lactating dairy cows

The objective was to compare reproductive performance of liquid sex-sorted (SS) semen with that of conventional (CON) semen in lactating dairy cows. Between 2011 and 2013, commercial dairy herds (n=101, 203, and 253 for 2011, 2012, and 2013, respectively) with predominantly Holstein-Friesian cows were enrolled in a contract mating program to produce surplus heifers for export using liquid SS semen. During the spring mating period, each herd was allocated with liquid SS semen at 50% of its daily requirement and the remaining daily requirement was allocated with CON liquid semen. Sperm for producing SS semen was sorted by Sexing Technologies NZ Ltd. (Hamilton, New Zealand) and then packaged using the liquid semen technology of LIC (Hamilton, New Zealand) at a dose of 1×106 sperm. Artificial insemination (AI) with liquid SS semen was carried out between 43 and 46h after collection. Conventional semen straws contained 1.25×106, 1.75×106, or 2×106 sperm for semen to be used on d 1, 2, or 3 after collection, respectively. Only CON inseminations on the same days as when SS semen was used were included in the comparison. Herd managers biased usage of SS semen toward cows with a longer postpartum interval before the mating start date (64.0 vs. 62.8 d), cows of higher genetic merit (NZ$107.0 vs. NZ$98.4), younger cows (5.1 vs. 5.2yr), and cows in which they had more confidence of being genuinely in estrus as measured by a lower percentage of short returns between 1 and 17 d (5.3 vs. 7.5%). After adjusting for these factors, the estimated difference in nonreturn rate between AI with SS and CON semen over the 3 seasons was −3.8 percentage points (SS=70.2% vs. CON=74.0%; SS/CON=94.9%). The estimated maximum difference in calving rate per AI between SS and CON semen was −3.1 percentage points for 2011 (SS=51.2% vs. CON=54.3%; SS/CON=94.3%) and −3.0 percentage points for 2012 (SS=49.7% vs. CON=52.6%; SS/CON=94.5%). Calving data for 2013 were not yet available. The percentage of heifer calves born to AI with SS semen was 87.0% for 2011 and 85.8% for 2012, both of which were lower than the expectation of 90% mainly due to misidentification of calf dams in seasonal dairy herds calving on pasture. In summary, results in this report showed that liquid SS semen only required half the dose rate of frozen SS semen to achieve a reproductive performance of over 94% of CON semen in lactating dairy cows. Careful planning and a robust distribution network are required to avoid semen wastage and to maximize the benefit of liquid SS semen.

Early versus standard interval postpartum IUD placement

Objectives: To compare intrauterine device (IUD) utilization at 3 months in women randomized to early (3 weeks) versus standard interval postpartum placement (6 weeks).

Post-partum anoestrus in tropical beef cattle: A systems approach combining gene expression and genome-wide association results

The length of the post-partum anoestrous interval affects reproductive efficiency in many tropical beef cattle herds. In this study, results from genome-wide association studies (Experiment 1: GWAS) and gene expression (Experiment 2: microarray) were combined in a systems approach to reveal genetic markers, genes and pathways underlying the physiology of post-partum anoestrus in tropically adapted cattle. The microarray study measured the expression of 13,964 genes in the hypothalamus of Brahman cows. A total of 366 genes were differentially expressed (DE) in the post-partum period, when acyclic cows were compared to cows that had resumed ovarian cycles. Associated markers (P<0.05) from a high density GWAS pointed to 2829 genes that were associated with post-partum anoestrous interval (PPAI) in two populations of beef cattle: Brahman and Tropical composite. Together the experiments provided evidence for 63 genes that are likely to influence the resumption of ovulation post-partum in tropically adapted beef cattle. Functional annotation analysis revealed that some of the 63 genes have known roles in hormonal activity, energy balance and neuronal synapse plasticity. Polymorphisms within candidate genes identified by this systems approach could have biological significance in post-partum anoestrus and help select Zebu (Bos indicus) influenced cattle with genetic potential for shorter post-partum anoestrus.

Cardiovascular effects of aerobic exercise training in formerly preeclamptic women and healthy parous control subjects

Women who have had preeclampsia demonstrate higher prevalence of metabolic syndrome (MetS), impaired vascular function, and increased sympathetic activity and are at increased risk of cardiovascular disease. The aim of this study was to assess the effects of 12 weeks of exercise training (70-80% maximum volume of oxygen utilization) in women who had had preeclampsia on physical fitness, components of MetS, vasculature, and autonomic functions compared with healthy control subjects. Our prospective case-control study included 24 normotensive women who had had preeclampsia and 20 control subjects who were matched for age and postpartum interval (all 6-12 months after delivery). Before and after training, we measured all components of MetS (ie, BP, lipids, glucose/insulin, and albuminuria), carotid intima media thickness (IMT) and brachial and superficial femoral artery endothelial function that used flow-mediated dilation (FMD). Autonomic activity was quantified with power spectral analysis (low-frequency/high-frequency power [LF/HF] ratio). At baseline, women who had had preeclampsia demonstrated higher values of most components of MetS. Compared with the control subjects, women who had had preeclampsia had increased IMT (580 ± 92 μm vs 477 ± 65 μm, respectively), impaired endothelial function (FMD brachial artery, 5.3% ± 2.2% vs 10.8% ± 3.5%, respectively; FMD superficial femoral artery, 4.9% ± 2.1% vs 8.7% ± 3.2%, respectively) and increased LF/HF power ratio (2.2 ± 1.0 vs 1.3 ± 0.4, respectively; all P < .05). In both groups, exercise training decreased values of most components of MetS and IMT, improved FMD, and concurrently reduced LF/HF. Despite these improvements, vascular and autonomic variables did not normalize by 12 weeks of training in women who had had preeclampsia. This study demonstrates that exercise training in women who had had preeclampsia and control subjects improves components of MetS, endothelial function, vascular wall thickness, and autonomic control. Nonetheless, trained women who had had preeclampsia only reached a cardiovascular status that is comparable with sedentary healthy control subjects.

Effect of dietary conjugated linoleic acid (CLA) on the metabolism and reproduction of dairy cows

Rumen-protected conjugated linoleic acid (CLA) reportedly improves fertility in lactating dairy cows by reducing the postpartum interval to first ovulation and enhancing the circulating insulin-like growth factor-I (IGF-I) levels. The objectives of this study were to evaluate the blood metabolites, hormones, follicular fluid (FF) and liver for the effect of CLA supplementation (50 g top-dressed daily from 15 days pre-partum to 65 days in milk –DIM -). Pre-partum Holstein cows (n = 24) were assigned to two treatments: a Control and CLA group (n = 12 cows/group). Dry matter intake (DMI) and milk production were recorded daily. At 26 DIM, ovulation was synchronized and at 34 DIM, plasma and FF were analysed for paraoxonase 1(PON) levels. Moreover plasma was analysed for IGF binding protein 2 and 3 (IGFBP). From 34 DIM, blood samples and FF from follicles &gt;9 mm were collected and analysed for estradiol, progesterone, IGF-I and lipoproteins. A liver biopsy was performed at 65 DIM and analysed for the expression of IGF-I, growth hormone receptor (GHR), pyruvate carboxylase (PC) and cytosolic phosphoenolpyruvate carboxykinase (PECK). CLA supplemented cows, compared to the control group, recorded a significant lower milk fat production, improved DMI and energy balance and recorded significant increased plasma concentrations of IGF-I, cholesterol, low density lipoprotein (LDL) and IGFBP-3 (interaction treatment x DIM). The concentration of IGF-I, high density lipoprotein (HDL) and LDL tended to be higher in FF than plasma. This study confirms the positive effects of dietary CLA supplementation on the metabolism, by improving the energy intake and reducing the negative energy balance. Moreover, the improvement of plasma IGF-I levels observed in this study, coupled with a better energy balance support previous studies showing a positive effect of CLA supplementation on reproduction. However, CLA did not alter the plasma and the FF concentration of PON, nor the liver gene expression.Keywords: Follicular fluid, liver gene expression, postpartum cows

Risk factors associated with multiple ovulation and twin birth rate in Irish dairy and beef cattle

The objective of this study was to quantify the phenotypic and genetic risk factors associated with multiple ovulations and twin births in cattle. Prevalence and cow- and herd-level risk factors associated with ovulation rate were determined using 40,617 ultrasonographic records of the reproductive tract from 27,907 dairy and beef cows from 738 commercial herds. Prevalence of twin births was estimated from the Irish national database containing 23,658,351 calving events from 8,546,695 cows from 125,251 dairy and beef herds; factors associated with twin births were determined using a random subsample of 505,200 calving events from 280,638 cows in 81,329 herds. The mean prevalence of multiple ovulations was 6.83% while the prevalence of twin births was 1.74%. Occurrence of both multiple ovulations and twin births was associated with the month of scan (P < 0.0001) and month of calving (P < 0.0001), respectively, and peaked in November for multiple ovulations and October for twin births. The likelihood of multiple ovulations increased with interval postpartum and peaked between 45 to 185 d postcalving, after which the likelihood declined. The likelihood of both multiple ovulations (P < 0.0001) and twin births (P < 0.0001) increased with increasing cow parity. A greater proportion of Holstein, Friesian, Simmental, Hereford, and Charolais breed fractions were associated with a greater likelihood of multiple ovulations. There was no difference between breed proportion of the cow and incidence of twin births, where all breed proportions examined, litter difference existed among breeds in their association with risk of twin births. Although multiple ovulations were lowly heritable (0.028 ± 0.003), their occurrence was repeatable (0.326 ± 0.342) while twin birth rate in cattle was lowly heritable (0.017 ± 0.004) and repeatable (0.018 ± 0.011). The genetic SD of the presence of multiple ovulations and twin births was 0.04 and 0.02, respectively, indicating considerable genetic variation, especially for multiple ovulations. A moderate genetic correlation (0.66 ± 0.16) existed between multiple ovulations and twin births.

Induction of cervical dilation for transcervical embryo transfer in ewes

BackgroundA major limitation in the application of assisted reproductive technologies in sheep arises from the inability to easily traverse the uterine cervix. The cervix of the non-pregnant ewe is a narrow and rigid structure, with 5–7 spiral folds and crypts that block its lumen. The first two folds closest to the vagina appear to be the greatest obstacle for the instrument insertion into the sheep cervix. Therefore, the dilation of the distal part of the cervix could provide the conformational change necessary to perform non-invasive transcervical procedures. The present study set out to assess the efficacy of Cervidil®, a patented dinoprostone (PgE2)-containing vaginal insert with a controlled-release mechanism, to safely induce sufficient cervical dilation for the purpose of transcervical embryo transfer (TCET) in cyclic ewes.MethodsThe transfer of frozen-thawed ovine embryos was attempted in 22 cross-bred Rideau Arcott x Polled Dorset ewes, with or without the pre-treatment with Cervidil® for 12 or 24 h prior to TCET.ResultsCervical penetration rate was significantly improved after Cervidil® pre-treatment, with 55% (6/11) of treated versus 9% (1/11) of control animals successfully penetrated (χ2-test, p < 0.05). Within the treated ewes that were penetrated, 67% (4/6) had been exposed to Cervidil(R) for 24 h and 33% (2/6) had had a 12-h exposure (p > 0.05). Variations in the age, weight, genotype, parity, lifetime lamb production (LLP) and post-partum interval (PPI) between penetrated and non-penetrated ewes were not significant (p > 0.05). The time taken to traverse the uterine cervix was negatively correlated (p < 0.05) with the age, parity, LLP and PPI. Progesterone assays and ultrasonographic examinations performed 25 days after ET confirmed pregnancy in 2 of 7 penetrated ewes, but no fetuses were detected ultrasonographically 55 days post-TCET.ConclusionsThe present results indicate a significant benefit of using Cervidil® for inducing cervical dilation during the mid-luteal phase in ewes but the reason(s) for impaired fertility after the transfer of frozen-thawed ovine embryos remains to be elucidated.

Optimising reproductive performance of beef cows and replacement heifers

A reproductively efficient beef cow herd is fundamental to meeting the protein and specifically, red meat demand of an ever increasing global population. However, attaining a high level of reproductive efficiency is underpinned by producers being cognisant of and achieving many key targets throughout the production cycle and requires significant technical competency. The lifetime productivity of the beef bred female commences from the onset of puberty and will be dictated by subsequent critical events including age at first calving, duration of the postpartum interval for each successive calving, conception and pregnancy rate and ultimately manifested as length of intercalving intervals and number of calves weaned over her lifetime. Puberty in heifers is a consequence of the interactive effects of genetics and both pre- and post-weaning nutrition. Early onset of puberty is essential to achieving the first main reproductive target for beef cow herds; first calving at 2 years of age. In calved heifers and mature cows, the onset of ovarian activity, postpartum is a key event dictating the calving interval. Again, this will be the product mainly of prepartum nutrition, manifested through body condition and the strength of the maternal bond between cow and calf, though there is increasing evidence of a modest genetic influence on this trait. Following the initiation of postpartum ovarian cyclicity, conception and subsequent pregnancy rate is generally a function of bull fertility in natural service herds and heat detection and timing of insemination in herds bred through artificial insemination. Cows and heifers should be maintained on a steady plane of nutrition during the breeding season, but the contribution of significant excesses or deficiencies of nutrients including protein and trace elements is likely to be minor where adequate pasture is available. While, increased efforts are being made internationally to genetically identify and select for more reproductively efficient beef cows, this is a more long-term strategy and will not replace the need for a high level of technical efficiency and management practice at farm level.

Reproductive performance of Arab mares in the Kingdom of Saudi Arabia

The aim of this study was to evaluate the reproductive performance of the Arab mares in the Kingdom of Saudi Arabia (KSA). Managers of 26 studfarms containing 1014 Arab mares at five districts were asked to complete a questionnaire on the reproductive efficiency of their mares. The mean age at first mating was 3.06 ± 0.5 years. Mares were mated equally in winter and all over the year. Natural mating was mostly used (76.9%). The means of estrus duration and estrus interval were 6.58 ± 1 days and 19.57 ± 1.8 days, respectively. The means of first service and over- all pregnancy rates and the number of cycles/pregnancy were 52.71 ± 20.2%, 83.72 ± 15.0%, and 1.46 ± 0.3, respectively, with no effect of the postpartum interval, district, or season. The average pregnancy duration was 335.5 ± 10.2 days. It was shorter in mares mated by day 9 postpartum than in those mated later (p < 0.05). The ratio of stallion/mares ranged from 1:4 to 1:24, with no correlation with the pregnancy rates or the number of cycles/pregnancy. Photoperiodic regulation and changes in the hypothalamic-hypophyseal axis of mares are usually associated with the seaso- nal reproductive activity of mares in the temperate but not in subtropical areas. Short duration of gestation for mares mated by day 9 after foaling may be related to the nutritional status of dams. The obtained data represent the first record of the reproductive performance of Arab mares in the KSA, which could be used to anticipate their performance under different managements. The Arab mares in the KSA are not seasonal and can reproduce efficiently all over the year. District and season did not influence the fertility.

A systems approach to determine the effect of changes in gene expression in adipose tissue on productive and reproductive efficiency in dairy cattle

In order to assess the patterns of metabolism that affect efficiency, an existing mechanistic metabolic model of dairy cows (Molly) was expanded to include transcriptional control of metabolism in adipose tissue and reproductive processes. Our objective was to test the effects of changes in gene transcription in adipose tissue on patterns of metabolism, reproductive processes and efficiency. The model describes the substrate sensitivity and maximum velocity for lipogenesis, esterification and lipolysis. Data were collected from first and second parity cows from various studies, and included nutrient intake, milk component output, changes in adipose tissue lipid, visceral and body protein and lipid, and metabolism rates in adipose tissue and gene transcription. The lipogenic pathways were primarily controlled by transcriptional changes, whereas lipolysis varied primarily by post-translational control. We used the difference in transcriptional and post-translational metabolic control to alter Vmax and Ks for lipogenesis and lipolysis; in addition, we modelled a range of energy costs for ion transport and protein turnover in liver, muscle and adipose tissues. Changing rates of lipogenesis and lipolysis (~four-fold) did not affect milk production or feed intake, but altered maintenance costs, fat accretion, energetic efficiency and reproduction. Increases in lipogenesis decreased postpartum interval to first ovulation; increases in rates of lipolysis increased the interval. Changes in metabolic rate from changing either adipose tissue metabolism or rate of ion transport and protein turnover affected rates of oestrogen and progesterone degradation, which affected follicular growth and corpus luteum function. This model may be used to help interpret genomic and transcriptomic data to pinpoint the most effective ways to select and manage for changes in productive and reproductive efficiency.

Effect of re-mating intervals on growth and reproductive performance of rabbits

The aim of this study was to know the effects of postpartum re-mating intervals on reproductive performances of does and growth of kits. Fifteen female New Zealand White crossbred rabbits were divided into three groups of equal numbers. They were re-mated within 24 hours, at 10 days and 28 days postpartum. Animals were individually caged in cells measuring 2'×2'×2'. Does were kept under natural lighting. Plastic nest boxes were supplied to does 3-4 days before parturition. They were reared up to four generation. Litter weight at birth was significantly (p&lt;0.05) higher at 10 days postpartum than within 24 hours and at 28 days postpartum intervals. Higher growth rate was observed in 10 days postpartum group comparing to other re-mating groups. Milk yield of the dams were significantly (p&lt;0.05) higher when dam re-mated at 10 days postpartum than those re-mated within 24 hours after parturition. Conception rate, gestation length of does, litter size at birth and weaning, litter weight at weaning, doe weight at mating, kidding, weaning and kid mortality did not differ significantly among the groups. Rabbit does re-mated at 10 days postpartum show maximum litter weight at birth, growth rate of kits and milk yield of dam.DOI: http://dx.doi.org/10.3329/bjas.v42i2.18497 Bang. J. Anim. Sci. 2013. 42 (2): 143-147

The influence of cow and management factors on reproductive performance of Irish seasonal calving dairy cows

Herd management record analysis facilitates accurate assessment of the current herd reproductive status; a crucial decision making tool to implement effective change. To determine the relative importance of cow and management factors on reproductive indices in moderate-yielding Irish seasonal-calving dairy herds, breeding records of 1173 cows were collected from 10 seasonal calving herds between 2007 and 2009. Backward-stepwise multivariable logistic regression analysis was utilised to determine the effect of cow factors including parity, calving timing, days post partum, heat detection accuracy and herd factors including herd size and heat detection efficiency on key reproductive indices. Mean farm six-week pregnancy and end of season not-in-calf rate were 46% (range 14–72%) and 22% (range 3–40%), respectively. Oestrous detection efficiency (P<0.001), timing of calving (P<0.001) relative to start of breeding, history of abnormal repeat intervals (P<0.001) and length of post partum interval (P<0.001) were each associated with lower six-week pregnancy rates. Timing of calving (P<0.001) and history of abnormal repeat intervals (P<0.001) were associated with higher not-in-calf rates. Herd size and cow parity were not associated (P>0.05) with either outcome when factors including existing calving pattern and heat detection accuracy and efficiency were accounted for. The existing spread in calving pattern, heat detection quality and length of voluntary waiting period were the most influential factors that reduced fertility performance in seasonal-calving herds.

Heifer calving date positively influences calf weaning weights through six parturitions1

Longevity and lifetime productivity are important factors influencing profitability for the cow-calf producer. Heifers that conceive earlier in the breeding season will calve earlier in the calving season and have a longer interval to rebreeding. Calves born earlier in the calving season will also be older and heavier at weaning. Longevity data were collected on 2,195 heifers from producers in South Dakota Integrated Resource Management groups. Longevity and weaning weight data were collected on 16,549 individual heifers at the U.S. Meat Animal Research Center (USMARC). Data were limited to heifers that conceived during their first breeding season. Heifers were grouped into 21-d calving periods. Heifers were determined to have left the herd when they were diagnosed not pregnant at the end of the breeding season. Heifers that left the herd for reasons other than reproductive failure were censored from the data. Heifers that calved with their first calf during the first 21-d period of the calving season had increased (P < 0.01) longevity compared with heifers that calved in the second 21-d period, or later. Average longevity for South Dakota heifers that calved in the first or later period was 5.1 ± 0.1 and 3.9 ± 0.1 yr, respectively. Average longevity for USMARC heifers that calved in the first, second, or third period was 8.2 ± 0.3, 7.6 ± 0.5, and 7.2 ± 0.1 yr, respectively. Calving period as a heifer influenced (P < 0.01) unadjusted weaning BW of the first 6 calves. Estimated postpartum interval to conception as a 2-yr-old cow was greater for females that calved in the first period as heifers but did not differ between heifer calving periods in subsequent calving seasons. In summary, heifers that calved early in the calving season with their first calf had increased longevity and kilograms weaned, compared with heifers that calved later in the calving season.

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 (250g/day/cow) was fed as a top dressing to the common lactating total mixed ration (TMR) from parturition to 21days 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.

Nurse Home Visits Improve Maternal/Infant Interaction and Decrease Severity of Postpartum Depression

To test the efficacy of the relationship-focused behavioral coaching intervention Communicating and Relating Effectively (CARE) in increasing maternal/infant relational effectiveness between depressed mothers and their infants during the first 9 months postpartum. Randomized clinical trial (RCT) with three phases. In this three-phase study, women were screened for postpartum depression (PPD) in Phase I at 6weeks postpartum. In Phase II, women were randomly assigned to treatment or control conditions and maternal/infant interaction was video recorded at four intervals postpartum: 6weeks, 3months, 6months, and 9months. Phase III involved focus group and individual interviews with study participants. Phase I mothers were recruited from obstetric units of two major medical centers. Phase II involved the RCT, a series of nurse-led home visits beginning at 6weeks and ending at 9months postpartum. Phase III focus groups were conducted at the university and personal interviews were conducted by telephone or in participants' homes. Postpartum mother/infant dyads (134) representative of southeastern New England, United States participated in the RCT. One hundred and twenty-five mother/infant dyads were fully retained in the 9-month protocol. Treatment and control groups had significant increases in quality of mother/infant interaction and decreases in depression severity. Qualitative findings indicated presence of the nurse, empathic listening, focused attention and self-reflection during data collection, directions for video-recorded interaction, and assistance with referrals likely contributed to improvements for both groups. Efficacy of the CARE intervention was only partially supported. Nurse attention given to the control group and the data collection process likely confounded results and constituted an unintentional treatment. Results suggest that nurse-led home visits had a positive effect on outcomes for all participants.

Early Pregnancy Diagnosis in Bovines: Current Status and Future Directions

An early and accurate diagnosis of reproductive dysfunctions or aberrations is crucial to better reproductive management in livestock. High reproductive efficiency is a prerequisite for high life-time production in dairy animals. Early pregnancy diagnosis is key to shorten the calving interval through early identification of open animals and their timely treatment and rebreeding so as to maintain a postpartum barren interval close to 60 days. A buffalo, the most important dairy animal in the Indian subcontinent, is known for problems related to high calving interval, late puberty, and high incidence of anestrus. Lack of reliable cow-side early pregnancy diagnosis methods further aggravates the situation. Several methods of pregnancy diagnosis are being practiced in bovine species, yet none qualifies as the ideal pregnancy diagnosis method due to the inherent limitations of sensitivity, accuracy, specificity, speed, and ease of performing the test. The advancement of molecular techniques like proteomics and their applications in animal research has given a new hope to look for pregnancy biomarker molecules in these animals. This review attempts to examine common pregnancy diagnosis methods available for dairy animals, while assessing the usefulness of the modern technologies in detecting novel pregnancy markers and designing future strategies for research in this area.

Assessment of phytochemical content in human milk during different stages of lactation

ObjectiveThe present study reports the presence of several carotenoids and flavonoids in human milk samples. MethodsSamples were collected from 17 women who delivered healthy term babies (≥37 wk of gestation) at 1-, 4-, and 13-wk postpartum intervals. ResultsEpicatechin (63.7–828.5 nmol/L), epicatechin gallate (55.7–645.6 nmol/L), epigallocatechin gallate (215.1–2364.7 nmol/L), naringenin (64.1–722.0 nmol/L), kaempferol (7.8–71.4 nmol/L), hesperetin (74.8–1603.1 nmol/L), and quercetin (32.5–108.6 nmol/L) were present in human milk samples with high inter-/intraindividual variability. With the exception of kaempferol, the mean flavonoid content in human milk was not statistically different among lactation stages. In contrast, carotenoids α-carotene (59.0–23.2 nmol/L), β-carotene (164.3–88.0 nmol/L), α-cryptoxanthin (30.6–13.5 nmol/L), β-cryptoxanthin (57.4–24.8 nmol/L), zeaxanthin (46.3–21.4 nmol/L), lutein (121.2–56.4 nmol/L), and lycopene (119.9–49.5 nmol/L) significantly decreased from weeks 1 to 13 of lactation. ConclusionThe observed differences in the relative concentrations of the two phytochemical classes in human milk may be a result of several factors, including dietary exposure, stability in the milk matrix, efficiency of absorption/metabolism, and transfer from plasma to human milk. These data support the notion that flavonoids, as with carotenoids, are dietary phytochemicals present in human milk and potentially available to breast-fed infants.