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This study aimed to evaluate the effects of different doses of equine chorionic gonadotropin (eCG; 200 and 300 IU) administered at the end of a fixed-time artificial insemination (FTAI) treatment protocol on ovulation, pregnancy, and twin rates in Bos taurus beef heifers. In addition, pregnancy losses in heifers with singleton and twin pregnancies were determined. A total of 2382 Angus heifers treated with a 6-day estradiol/progesterone-based protocol for FTAI (J-Synch protocol) were randomly allocated to two experimental groups to receive 200 or 300 IU of eCG administered intramuscularly at the time of intravaginal progesterone device removal; FTAI was performed from 60 to 72 h after device removal. The pregnancy rate did not differ (P = 0.89) between the 200 and 300 IU eCG groups. The number of corpus luteum induced by both eCG doses was determined by ultrasonographic examination 14 days after insemination and those treated with 300 IU of eCG had a greater double ovulation rate (P < 0.05). In addition, 300 IU eCG treated heifers had a higher twinning rate on day 30 of gestation (P < 0.05) and parturition (P < 0.05). Pregnancy losses from 30 days of gestation to calving did not differ between heifers treated with 200 and 300 IU of eCG (P = 0.70). However, regardless of the experimental group, heifers bearing twins had greater pregnancy losses than heifers with singletons (P < 0.05). In conclusion, reducing the dose of eCG from 300 to 200 IU under FTAI treatment protocol decreases double ovulation and twinning rates, maintaining a similar pregnancy rate in heifers. Nulliparous cows carrying two fetuses suffer greater pregnancy losses than cows with singletons. • Different doses of eCG were evaluated in a progesterone-based protocol for FTAI. • Reducing from 300 to 200 IU eCG maintained similar P/AI. • Twinning rate was lower with 200 IU eCG. • Those heifers bearing twins, suffer greater pregnancy losses than singletons. [ABSTRACT FROM AUTHOR]

Establishing methods for evaluating genomic estimated breeding values of bovine embryos can potentially increase the efficiency of breeding programs by transferring only embryos with a high genomic estimated breeding value. This may be achieved by analyzing DNA from trophectoderm biopsies. However, manipulation of bovine embryos is associated with a risk of impaired conceptus health. More knowledge on the health implications of embryonic handling procedures is required. In this study, we followed pregnancies after transfer of in vitro-produced (IVP) embryos and assessed the health of the offspring during the first 2 weeks of life. Three groups of calves were studied: i) freshly transferred non-biopsied embryos (39 transfers, 17 calves; Group B-/C-); ii) biopsied and freshly transferred IVP embryos (42 transfers, 21 calves; Group B+/C-); iii) biopsied and cryopreserved IVP embryos (17 transfers, 6 calves; Group B+/C+). Blood biochemical and hematologic values were compared between groups and to a control group of 13 calves produced by conventional artificial insemination. The pregnancy rate on day 50 and the calving rate did not differ among the groups, but the average gestation length of the B+/C+ group was significantly shorter and with wider variation than the two other groups. There was a tendency toward a higher average body weight at birth in group B+/C+ (45.1 kg) and the standard deviation in body weight was larger (11.7 kg) compared to the B-/C- (39.5 kg; 3.2 kg) and B+/C- (41.8 kg; 6 kg) groups. Body weight on day 14 was higher in the B+/C+ calves compared to the other groups. There was no difference in the biochemical and hematological values at birth between the groups and these were within the normal range. However, when compared to a group of calves produced by standard artificial insemination, significantly higher concentrations were found for the hepatic-related enzymes ALAT, ASAT, ALP, and GGT in group B-/C-and B+/C-, while only higher ALP concentrations were found in B+/C+ calves. The biochemical findings indicate higher heterogeneity in IVP calves compared to calves produced by artificial insemination. The more manipulated IVP embryos also showed increased heterogeneity in body weight at birth, with a shift toward heavier calves, which calls for closer attendance at parturition to handle dystocia in a timely manner and minimize fetal losses. • The more manipulated IVP embryos showed increased heterogeneity in body weight at birth, with a shift toward heavier calves. • A variation in biochemical values indicate higher heterogeneity in IVP calves compared to calves produced by AI. • Biochemical and hematological values were within normal range. [ABSTRACT FROM AUTHOR]

Context: Reducing livestock emissions, the largest single contributor to agricultural emissions, is increasingly recognised as a high priority. The low biological efficiency of beef cattle, due to their long gestation period, long generational interval, and propensity to be uniparous, contributes to the high methane emissions intensity (kg CO2-e/kg product) of beef compared to most other food products. Aims: We evaluate the potential of increasing the frequency of multiparous births (twinning) as a pathway to reducing the methane intensity of beef and the net methane emissions of intensive beef systems. Methods: We simulate a uniparous herd structure and emissions profile using GrassGro™ livestock systems modelling software and then calculate the effects of an increasing frequency of multiparous births (twinning), up to 1.53 calves per cow joined, on methane emissions. Key results: Our results demonstrate that beef from calves reared as twins has a 22% lower methane intensity than beef from a single reared calf. Although twinning reduces the methane intensity of beef, at the herd level, net methane emissions could rise by as much as 23% at 1.53 calves per cow joined if overall herd size is allowed to grow through an increased number of calves. If we decrease stocking rates, whilst also increasing twinning rates, it is possible to reduce net emissions by up to 14%, without changing productivity. Conclusions: Our results illustrate the significant potential of twinning to decrease the methane intensity of beef and to increase the productivity per cow in intensive beef systems. Implications: Despite this, twinning is unlikely to be a viable net emissions reduction pathway – as twinning will increase stocking rate unless herd structure is altered – unless a commercial or policy driver to reduce net methane emissions is established. Beef has a high emissions intensity due in part to the low reproductive rate of cattle. We evaluated if increasing the rate of twinning offers a pathway to reducing the methane intensity of beef by increasing biological efficiency, our results show that beef from twin reared calves has a 22% lower methane intensity. However, twinning is unlikely to be a viable net emissions reduction pathway unless a commercial or policy driver to reduce net methane emissions is established. [ABSTRACT FROM AUTHOR]

Synchronization of estrus involves handling the estrus cycle so that a large number of cows can be bred at approximately the same time. Proper cow/heifer selection as well as efficient coordination are all key elements for the success of synchronization programs which were lacking in the study area. The study was conducted with the objective to evaluate the effect of Alfaglandin C and fixed factors on estrus synchronization and efficiency of Artificial Insemination (AI) in North Shoa zone of the Oromia region. The study population encompassed indigenous and crossbred cows and heifers found in six purposively selected kebeles (smallest administrative unit within a district) from the three selected districts (Wucale, Dagam and Kuyuu). Multistage sampling procedure was used to select target districts, kebeles and experimental cows/heifers. A total of 180 cows and heifers fulfilling estrus synchronization criteria were selected purposively and injected with synchronizing hormone (Alfaglandin C). The level of significance among categorical variables was determined using the chi-square (ω²) test. About 70.6% of the cows and heifers injected with Alfaglandin C exhibited estrus. Exhibition of estrus following hormone injection was significantly (p<0.05) lower in Wuchale district compared with that of the other two districts. Likewise, the agroecology, farming system, herd group, and breed had a significant (p<0.05) effect on estrus exhibition. Among cows and heifers inseminated following estrus exhibition, 62.2% conceived as confirmed by pregnancy diagnosis (PD) test conducted at 45-day post AI, which dropped to 58.3% as observed by the PD test conducted three months' post AI. Agroecology, farming system, herd group, and genotype of cows and heifers showed significant (p<0.05) influence on the conception rate (CR). The highest CR was observed among cows of Kuyuu district, which was significantly (p<0.05) different from that of the other two districts. The overall calving rate was 91.1%. The semi-intensive part of the study also showed better estrus synchronization response and better reproductive performances which directly associated with the management practices. Treating industrial byproducts, better management, and promoting AI can achieve better estrus synchronization and efficiency of artificial insemination. [ABSTRACT FROM AUTHOR]

The study was conducted before the ignition (before October 2020) of the war in Tigray Region, Ethiopia. Artificial insemination (AI) is the first generation biotechnology and is one of the assisted reproductive techniques (ART) that greatly plays for a faster genetic improvement of farm animals. Though AI was implemented in cattle crossbreeding for many decades in Ethiopia, there is quite insignificant national output of crossbred cattle population (1.54 %). The aim of the survey was to assess the efficiency of AI service in cattle production in the Western Zone of Tigray Region, Ethiopia. Twenty (20) Kebeles and 353 small-scale farmers were purposively involved in the household face-to-face survey interview. The data were analyzed using Statistical Package for Social Sciences (SPSS), and summarized by mean, frequency and percentages. The survey indicated that the existing reproductive efficiency of cattle AI service in the Western Zone of Tigray Region, Ethiopia was extremely poor. The mean number of services per conception (NSC) was very high that could be due to mainly inappropriate heat detections. The recommended, acceptable and excellent grade of NSC fall in the range of 1 − 1.7. The overall conception rate at first insemination (CRFI) was also very poor (20.4 %) and thus calving rate (CR) was poor (20.5 %). About one-third (33.4 %) of the respondents indicated that cows and heifers exhibited heat in 0:01 − 6:00 am of the day. About 30.9 % and 28.6 % of the respondents reported that their cows and heifers were inseminated in 9 − 12 hours and 4 − 8 hours after the onset of heat, respectively. The majority (70.8 %) of the respondents did not practice controlled mating and breeding, and the first preference of 50.1 % of the respondents was natural mating. The most common source of bulls for about 34.3 % of the respondents was from neighbors and followed by own bred bulls (30.0 %). Cattle AI feasibility study and identification of AI strategic interventions should be the first focus to improve the existing poor AI efficiency of the study area. [ABSTRACT FROM AUTHOR]

Under natural and well-managed conditions, the buffalo has good reproductive and productive indices. However, in vitro embryo production (IVEP) has been used commercially to maximise the number of elite animals. In this species, several factors (donor management, in vitro culture medium, semen, in vitro conditions, embryo transfer) still affect the IVEP results. In addition, the cost of this technique is very high for this purpose. Therefore, more studies, as well as adequate plans, are needed to achieve this objective efficiently. In this review, we discussed the current commercial status, influencing factors (in vivo and in vitro), and the progress and future challenges of IVEP in buffalo. A total of 81 references were used from 1979 to 2022. The relevant data or literature were searched using the following databases: Google, ResearchGate, Science Alert, Science Direct and PubMed, using the following keywords: buffalo oocytes/COCs, buffalo embryos, pregnancy and calving or live birth rate after embryo transfer. The best maturation, cleavage and blastocyst rates in the in vitro production of buffalo embryos were 95.8, 75.2 and 33.4%, respectively. The pregnancy and live birth rates ranged from 22.2% to 43.5% and from 15.3% to 36.5%, respectively, after the transfer of fresh embryos produced in vitro to the recipients. This review will help to contextualise IVEP in buffaloes, as well as create an adequate plan for implementing IVEP in buffaloes.

Under natural and well-managed conditions, the buffalo has good reproductive and productive indices. However, in vitro embryo production (IVEP) has been used commercially to maximise the number of elite animals. In this species, several factors (donor management, in vitro culture medium, semen, in vitro conditions, embryo transfer) still affect the IVEP results. In addition, the cost of this technique is very high for this purpose. Therefore, more studies, as well as adequate plans, are needed to achieve this objective efficiently. In this review, we discussed the current commercial status, influencing factors (in vivo and in vitro), and the progress and future challenges of IVEP in buffalo. A total of 81 references were used from 1979 to 2022. The relevant data or literature were searched using the following databases: Google, ResearchGate, Science Alert, Science Direct and PubMed, using the following keywords: buffalo oocytes/COCs, buffalo embryos, pregnancy and calving or live birth rate after embryo transfer. The best maturation, cleavage and blastocyst rates in the in vitro production of buffalo embryos were 95.8, 75.2 and 33.4%, respectively. The pregnancy and live birth rates ranged from 22.2% to 43.5% and from 15.3% to 36.5%, respectively, after the transfer of fresh embryos produced in vitro to the recipients. This review will help to contextualise IVEP in buffaloes, as well as create an adequate plan for implementing IVEP in buffaloes. [ABSTRACT FROM AUTHOR]

This study aimed to determine the number of reproductive efficiency parameters including service per conception, conception rate, calving rate, and non-return rate for broilers in Kalipuro District, Banyuwangi Regency. The secondary data was collected from the Banyuwangi District Agriculture Office. This research is also intended to dissect factors related to the S/C, CR, CvR, and NRR figures with descriptive analysis, including bio reproduction mastery factors, service factors, and feed factors. The primary data was collected from beef cattle breeders in Kalipuro District, Banyuwangi Regency. In addition, there were IB implementation factors whose data were obtained from questionnaires to inseminators in Kalipuro District, Banyuwangi Regency. The number of S/C broilers in Kalipuro Subdistrict, Banyuwangi Regency was good maintenance, in January-March 2020 of 1.71, 1.99, and 1.74, meanwhile, the number of CR were 58%, 50% 57%, CvR for January-March were 44%, 84%, 53% and NRR for January, February and March were 41%, 49%, and 46%, respectively, were below the standard rate.

Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p

The present study aimed to assess the relationship of Growth Differentiation Factor 9 (GDF9) genotypes with calving rate, Follicle-stimulating hormone (FSH), and Estradiol (E2) in the Iraqi Holstein-Friesian breed. A number of 15 blood samples were collected from a mother of dizygotic twin birth (DZTB) (with high calving rate records), and another blood sample was collected from 15 single birth (SB) cows. The DNA was extracted and six primers were designed for PCR and sequencing analysis. The FSH and E2 levels were tested through the estrus phase for the two groups (n=10 in each group). The sequence evaluation revealed the presence of two single nucleotide polymorphisms (SNPs) in exon II: A (1109) T and G (1133) A. The genotypic frequency for mutant genotypes was higher significantly (P

The purpose of this study was to analyze the success of the artificial insemination (AI) program in local cattle in Pante Bidari District, East Aceh Regency, Aceh Province. It was conducted in five villages: Alue Ie Mirah, Buket Bata, Grong-Grong, Meunasah Tunong, and Paya Demam Empat. The survey method was employed in this study. The respondents were selected by using purposive sampling method. There were 40 breeders and 3 inseminators included as the respondents. To be involved in the study, the breeders had to meet certain criteria, such as having an experience of breeding local cows, at least twice using the AI system. As for the inseminators, they were required to have a permit from the East Aceh Livestock Service. The results showed that the conception rate (CR) was 76.45%; the service per conception (S/C) was 1.22; the calving interval (CI) was 12.70 months, and the calving rate (CvR) was 89.92%. This study concluded that the implementation of the artificial insemination program in Pante Bidari District, East Aceh Regency, has been running effectively.

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The present study aimed to assess the relationship of Growth Differentiation Factor 9 (GDF9) genotypes with calving rate, Follicle-stimulating hormone (FSH), and Estradiol (E2) in the Iraqi Holstein-Friesian breed. A number of 15 blood samples were collected from a mother of dizygotic twin birth (DZTB) (with high calving rate records), and another blood sample was collected from 15 single birth (SB) cows. The DNA was extracted and six primers were designed for PCR and sequencing analysis. The FSH and E2 levels were tested through the estrus phase for the two groups (n=10 in each group). The sequence evaluation revealed the presence of two single nucleotide polymorphisms (SNPs) in exon II: A (1109) T and G (1133) A. The genotypic frequency for mutant genotypes was higher significantly (P<0.01) in DZTB cows (with calving rate), as compared to wild genotypes at the same loci. On the other hand, the wild genotypes recorded a significant increment (P<0.01) for SB cows, when compared to mutant genotypes in the same loci. Moreover, a significant rise (P<0.05) was reported in E2 and FSH levels for DZTB cows and mutant genotypes (P<0.01) against SB cows and wild genotypes in 0 and 24 h of estrus phase, respectively. Furthermore, non-significant differences were recorded in E2 concentration among the same genotypes at the same period. In conclusion, the GDF9 exon II SNPs increased the calving rate in Holstein-Friesian cows. The blood FSH and E2 concentrations were higher in the DZTB cows and control the superovulation. Finally, these SNPs can be regarded as markers to accelerate the breeding programs and used in embryo transfer and in vitro embryo production for Iraqi Holstein-Friesian cow breed. [ABSTRACT FROM AUTHOR]

This study address historical legacy of South Africa that has dual economies resembling low and high income beef sectors. Low-income herds are farmed mainly under communal village or land reform farms. The study focused on providing assisted reproductive technologies (ARTs) to the low-income sector including finding challenges to its implementation and adoption. The study was conducted in Limpopo, Mpumalanga and KwaZulu-Natal provinces using mixed methods that looked at cows and sectors stakeholders. Data collected and evaluated on cows included breed type, frame size, body condition, age parity, and lactation status. Cows were exposed to ART through synchronisation, oestrus detection, fixed time artificial insemination and pregnancy diagnosis. Qualitative data was collected to study perception of key stakeholders on ART implementation and adoption. Chi-Square Test was computed to determine the association among cow factors. Qualitative data was collected, coded and managed into themes using Nvivo Version 11. Themes that emerged were interpreted using critical social and systems thinking. Conception rate was not independent of provinces (P < 0.05), cow body condition score (BCS) and body frame size. KwaZulu-Natal cows had the highest conception rate at 66% (P < 0.05) than Limpopo (44%) and Mpumalanga (60%) provinces. Cows with a BCS higher than 3.5 had higher conception rate (P < 0.05) than those with BCS of

Killer whales, Orcinus orca, are a cosmopolitan species with large ecological and demographic variation across populations. Population-specific demographic studies are, therefore, crucial in accurately assessing the status and trends of local killer whale populations. Such studies require long-term datasets and remain scarce, particularly in the Southern Ocean where detailed population specific studies have only been conducted at a single archipelago – Îles Crozet. Here, we analysed 12 years of capture–recapture data (comprising nearly 90 000 identification photographs taken from 2006 to 2018) of killer whales at subantarctic Marion Island (46°54′S, 37°45′E) to estimate the abundance, survival and growth rate of this population. Demographic parameters were estimated using multistate capture recapture models, and Pradel Survival-Lambda and POPAN single-state models implemented in the program MARK. Annual survival probability (0.98 [95% CI: 0.96–0.99]) was constant over time, and no important differences between sexes and age-classes (calves, juveniles, adults) were found. This estimate of survival suggests a life expectancy of approximately 48 years. Realised mean population growth rate (λ) was 1.012 (0.987–1.037) with an estimated population size of 54 (54–60) individuals and a mean calving rate of 0.13 (0.06–0.20) calves born per year per reproductive female. The survival and reproduction rates of killer whales at Marion Island are similar to those of killer whale populations in the eastern North Pacific, Norway and Îles Crozet. However, subtle differences in survival and reproduction rates are present. These are likely the result of local differences in resource abundances, historical impacts on social structure and/or stressors. Also, the presence and scale of fisheries (legal and illegal) in the area may provide opportunities for direct interactions with fishing activities impacting survival and reproduction rates. [ABSTRACT FROM AUTHOR]

The study aimed to determine the effect of assisted reproductive technologies on cow productivity. The study was conducted with organized cattle farmers under communal and emerging farming systems from three provinces, namely; Limpopo, Mpumalanga and KwaZulu-Natal. Cow parameters evaluated were breed type, body frame size, parity, age, body condition score and lactation status. An ovsynch protocol was used during the oestrous synchronization process. All experimental cows were artificially inseminated with frozen-thawed Nguni semen. The study recorded a calving rate of 48%. The dominant cattle breed types were the Bonsmara, Brahman and Nguni. Chi-Square Test of Independence were computed between calving rate and individual factors. The data were further modelled using logistic regression model for SAS, modelling the probability for success. Calving rate was not independent of provinces, districts and body condition score (P

In most extensive beef production systems in South Africa, calves are weaned at specific dates. This implies that cows that calve late in the season wean younger and lighter calves. In the current study, Bonsmara cows were mated naturally after synchronization over six years (2009 - 2014) in an extensive production system on natural veld in the Central Bushveld bioregion. Within the herd, 50% of cows were synchronized prior to the commencement of the summer breeding season and they were mated naturally for 90 days. The results indicated that calving rate did not differ significantly between cows that were synchronized and non- synchronized. However, there was a significant difference between years in calving rate. Oestrous synchronization prior to natural breeding influenced the average days to conception. The difference in percentage of cows that calved within 293 days of the onset of the breeding season between those that were oestrous synchronized and non-synchronized was 15% in favour of the synchronized cows. Although calves from synchronized cows achieved higher average weaning weights, the cost implications of synchronization offset the benefit of higher calf weights. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate risk factors, serum minerals, and metabolites associated with non-infectious abortion and calving rates of Egyptian buffaloes. Data were obtained from 364 pregnant buffaloes of different ages and parities over 7 years from 2014 to 2020. Body condition score (BCS) was a risk factor regarding abortion and calving; the thinnest buffaloes were more likely to abort and less likely to calving than those with body energy reserves. In comparison with the spring season, aborting probability decreased 49.7% the odds ratio (OR = 0.503), while the chance of calving increased 72.1% (OR = 1.721) during winter. The parity was another significant factor related to abortion and calving rates; multiparous buffaloes were less likely to abort and more likely to calving than primiparous. Dry buffaloes had 88.2% (OR = 0.118) lesser odds of abortion and six times (OR = 6.012) more likely to give birth than those lactating. The sex of the fetus was not a risk factor regarding abortion or calving. Other variables significantly associated with abortion rate were glucose and copper in the sera of aborted buffaloes were significantly higher (p < 0.05), and those of urea, uric acid, total protein, total cholesterol, phosphorus, magnesium and iron were significantly (p < 0.05) lower than a normal pregnancy. In conclusion, the present results emphasize that the identification of the risk factors, serum minerals and metabolites associated with fetus abortion of Egyptian buffalo may provide useful information, which assists to construct suitable preventive measures to raise reproductive performance.

This study was conducted with the aim of determining the probable effects of different real interest rates (RIR: 5, 6 and 7%), some key breeding criteria such as calving rate (CR: 80, 85 and 90%) and mean lactation milk yield per milking cow (MLML: 5000, 6000 and 7000 kg) on the financial evaluation indicators such as Benefit Cost Ratio (BCR) for a dairy cattle farm investment project taken as model, consisted of 100 heads of Holstein cows, which was established and operated during 20 years period in Turkey. In the study, firstly, current investment and annual operating costs for that kind of dairy cattle farm were determined according to optimal workmanship, housing, maintenance, feeding and health protection and then revenues were calculated from current sale prices of raw milk, slaughtered/breeding animal and manure. For each assumed different real interest rate, calving rate and mean lactation milk yield per milking cow, the parities of unit (1 kg) sale price of raw milk to unit (1 kg) cost of concentrate feed (M/F-parity) (current unit cost of concentrate feed was assumed as to be 1.00 Turkish Lira (TL) were calculated to make BCR that is one of the financial evaluation criteria for the investment projects, as to be 1.00. Calculations showed decreasing each 1% of the real interest rate in Turkey, increasing each 5% of calving rate and increasing each 1000 kg of mean lactation milk yield per milking cow had, separately, about 5-12% positive effect on the parity of unit (1 kg) sale price of raw milk to unit (1 kg) cost of concentrate feed.

The aim of this study was to analyse the effect of supplementary feeding of DHA (Docosahexaenoic Acid) rich algae product (Algae STM Alltech Inc.) on production of milk, fat and protein as well as on reproduction of high yielding Holstein dairy herd. Field trial was set up on Top 10 dairy farm in western part of Slovakia, under commercial conditions. The data of high yielding dairy cows, separated in two groups of 30 (control) and 29 (trial) animals, were recorded for period of 3 subsequent months from October to December 2015. Animals were fed once a day Total Mixed Ration based diet with different feed mixture composition in trial group (+100 g Algae STM Alltech Inc. per cow and day). Performance data were collected in accordance with official milk recording system of Breeding Services of Slovak Republic s. e. and milk samples were collected once per month according to the A4 standard methodology. The control group showed higher level of milk production compared to trial. Our study indicated that the feeding of algae caused milk fat depression and generally lower protein content in milk. Significant impact of algae feeding was found also for the level of urea in milk. In addition, the supplementary feeding of DHA may represent effective strategy to increase the percentage of pregnancies per inseminations in lactating dairy cows.

This study aimed to evaluate the quality of frozen semen of Bali bull resulted from sexing procedure on calf or offspring production with desired sex. The tested sperm of Bali bull were collected from Bali bull raised at Regional Artificial Insemination Center of Riau Province (BIBD Riau). The study was carried out in 2 stages. The first stage was X and Y chromosome separation by albumin method. The extender used in the sexing procedure is trice citrate fructose and egg yolk. The second stage was mainly testing the sexed sperm collected in 60 Bali cow in Langkat Village, Bengkalis Regency. To determine the quality of post thawing frozen semen collected from the sexing procedure, the study evaluated motility, viability, mortality, abnormality and plasma membrane integrity of the spermatozoa. The pregnancy rate, calving rate, and birth accuracy of inseminated sexed sperm to offspring’ sex were also evaluated. The evaluation resulted in motility (66.3-75.3%), viability (70-78.5%), plasma membrane integrity (60-65.8%), abnormality (6.05-8.05%), mortality (20.05-30.05%), and pregnancy rate (83.33-90%). The calving rate on this study was 100% with the birth accuracy of 81.8% for male offspring and 40% for female offspring. As conclusion, the sexed sperm evaluated on this study have fairly good fertility.

• There is a social demand for improved animal welfare in food producing. • Animal welfare can be estimated by the Welfare Quality Protocol in dairy cows. • Reproductive performance is a componment of productivity in dairy cows. • Calving to first service interval and calving rate were related to welfare. • Improved welfare was related to higher reproductive performance. This study aimed to investigate the relationship between cow reproductive performance and welfare evaluated at the herd level using the Welfare Quality protocol. The 11 criteria, four principles (good feeding, good housing, good health and appropriate behavior, scale 0–100) and overall welfare category (excellent/enhanced/acceptable/not classified = poor welfare) were included as risk factors for calving to first service interval (CFSI) and calving rate (CR). The confounding factors cow breed, parity, season of calving and AI, calving to AI interval, rank of AI (1–3) and milk production were taken into account. The sample included 3951 AIs (2172 AI1, 1182 AI2, 597 AI3) in 124 French commercial dairy herds. Median CFSI was shorter for the cows bred in herds with a higher overall welfare category (median 75 and 76 days in enhanced and acceptable herds vs. 86 in poor welfare ones, P = 0.02). The scores for absence of injuries and expression of social behavior tended to be associated with CFSI (P < 0.10). Calving rate (34.5%) was not related to the overall welfare category. However, CR was positively related to the good housing score and a positive trend was observed with the scores for absence of prolonged hunger and absence of injuries. In conclusion, this study confirms a positive relationship between CFSI and welfare in dairy cows with no explicit links with specific aspects of animal welfare. [ABSTRACT FROM AUTHOR]

Calving rate in communal cattle influences both food security and socio-economics in rural households. A previous study indicated that scrotal damage caused by ticks could affect the fertility of communal bulls and reduce the annual calving rate. The objectives of the study were to investigate the annual calving rate in communal herds by counting calves during herd visits, perform breeding soundness examinations on bulls and identify adult ticks attached to their genitalia. This prospective longitudinal survey was based on participatory rural appraisal. Calving rates were estimated in cows (n = 2398) from 100 randomly selected communal herds in Moretele over 12 months in 2013, during routine visits by animal health technicians. Randomly selected bulls (n = 50) from these herds were tested for Brucella abortus, Trichomonas foetus and Campylobacter fetus subspecies venerealis. The calving rate was 35.86% (0.359). The mean scrotal circumference was 37.63 ± 3.42 cm. Total sperm motility was 78.73 ± 35.73%; progressive sperm motility was 27.39 ± 15.81% and non-progressive sperm motility was 51.34 ± 19.92%. Thirty-five of the 38 bulls examined for breeding soundness exhibited severe scrotal and preputial lesions caused by the adult ticks Amblyomma hebraeum and Hyalomma rufipes. Tick control methods used included spraying (n = 20), pour-on (n = 11), no control (n = 1) and various (n = 18). It was concluded that in Moretele genital tick damage had a more serious impact on the fertility of communal bulls than contagious diseases. Targeted acaricidal spot treatment of the genitalia of communal bulls to prevent infestation is recommended, as tick control strategies used by farmers appeared to be inadequate. [ABSTRACT FROM AUTHOR]

The study aimed to determine the effect of assisted reproductive technologies on cow productivity. The study was conducted with organized cattle farmers under communal and emerging farming systems from three provinces, namely; Limpopo, Mpumalanga and KwaZulu-Natal. Cow parameters evaluated were breed type, body frame size, parity, age, body condition score and lactation status. An ovsynch protocol was used during the oestrous synchronization process. All experimental cows were artificially inseminated with frozen-thawed Nguni semen. The study recorded a calving rate of 48%. The dominant cattle breed types were the Bonsmara, Brahman and Nguni. Chi-Square Test of Independence were computed between calving rate and individual factors. The data were further modelled using logistic regression model for SAS, modelling the probability for success. Calving rate was not independent of provinces, districts and body condition score (P < 0.05). Cows in Mpumalanga had more chances to calve than those in Limpopo and KwaZulu-Natal. Nguni cattle breed had more chances to calve down than Brahman (P = 0.815), but less chances than Bonsmara cattle breed (P = 1.630). It is recommended for rural farmers to farm with small framed animals because of their higher chances to calve down compared to other cattle breed. [ABSTRACT FROM AUTHOR]

Early embryonic development may be negatively affected by insufficient progesterone (P4) production. Therefore, the aim of our study was to increase P4 by gonadotropin-releasing hormone (GnRH) and/or human chorionic gonadotropin (hCG) treatments after inducing oestrus by prostaglandin (PG) treatment. Lactating Simmental dairy cows (n = 110), between 1 to 5 lactations, with an average milk production of 6,500 1/305 days, at 40–80 days postpartum were used and grouped as follows: (1) PG + GnRH treatment at AI (GnRH group), (2) PG + hCG treatment at day 7 after AI (hCG group), (3) PG + GnRH at AI + hCG treatment at day 7 after AI (GnRH/hCG group), and (4) spontaneous oestrus (C: control group). All animals were double inseminated (at the time of oestrus detection and 12 ± 2 h thereafter). Blood serum and milk samples were collected at the day of observed oestrus (day 0), and 14, 21 and 28 days after AI. Serum P4 was determined using a commercial radioimmunoassay (RIA) test (INEP, Zemun), and milk P4 was determined using enzyme-linked immunoassay (ELISA) test (NIV Novi Sad). Pregnancy status was confirmed by ultrasonography between days 28 and 35 after AI. Differences of serum or milk P4 medians, pregnancy (and calving) rate were determined using Dunn’s Multiple Comparison Tests and Z test, respectively. Serum P4 medians were significantly higher at days 14, 21 and 28 after AI in the hCG-treated animals, indicating increased luteal activity, with a similar tendency in whole milk P4 values. Treatment with hCG during the early luteal phase significantly contributed to the maintenance of gestation at days 28–35 after AI, and also increased the calving rate in Simmental dairy cows. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of semen diluent on calving rate (CR) following artificial insemination with liquid bull semen stored for up to 3 d postcollection. In experiment 1, the effect of storing liquid semen maintained at a constant ambient temperature in 1 of 7 different diluents [Caprogen (homemade), OptiXcell, BioXcell, BullXcell, INRA96, NutriXcell, or AndroMed (all commercially available)] on total and progressive motility was assessed on d 0, 1, 2, and 3 postcollection. In experiment 2, the field fertility of liquid semen diluted in Caprogen, BioXcell, or INRA96 and inseminated on d 1, 2, or 3 postcollection was assessed in comparison to frozen-thawed semen (total of n = 19,126 inseminations). In experiment 3, the effect of storage temperature fluctuations (4 and 18°C) on total and progressive motility following dilution in Caprogen, BioXcell, and INRA96 was assessed on d 0, 1, 2, and 3 postcollection. In experiment 1, semen stored in Caprogen, BioXcell, and INRA96 resulted in the highest total and progressive motility on d 1, 2, and 3 of storage compared with OptiXcell, BullXcell, NutriXcell, and AndroMed. In experiment 2, an effect of diluent on CR was found as semen diluted in BioXcell had a lower CR on d 1, 2, and 3 of storage (46.3, 35.4, and 34.0%, respectively) in comparison with Caprogen (55.8, 52.0, and 51.9%, respectively), INRA96 (55.0, 55.1, and 52.2%, respectively), and frozen-thawed semen (59.7%). Effects were found of parity, cow fertility sub-index, as well as the number of days in milk on CR. In experiment 3, when the storage temperature of diluted semen fluctuated between 4 and 18°C, to mimic what occurs in the field (nighttime vs. daytime), BioXcell had the lowest total and progressive motility in comparison to Caprogen and INRA96. In conclusion, diluent significantly affected sperm motility when stored for up to 3 d. Semen diluted in INRA96 resulted in a similar CR to semen diluted in Caprogen and to frozen-thawed semen, whereas that diluted in BioXcell resulted in a decreased CR. Consistent with this finding, semen diluted in BioXcell was less tolerant of temperature fluctuations than that stored in Caprogen or INRA96. Given that it can be used directly off the shelf, INRA96 may be a suitable alternative to Caprogen for the storage of liquid bull semen. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the effect of supplementary feeding of DHA (Docosahexaenoic Acid) rich algae product (Algae STM Alltech Inc.) on production of milk, fat and protein as well as on reproduction of high yielding Holstein dairy herd. Field trial was set up on Top 10 dairy farm in western part of Slovakia, under commercial conditions. The data of high yielding dairy cows, separated in two groups of 30 (control) and 29 (trial) animals, were recorded for period of 3 subsequent months from October to December 2015. Animals were fed once a day Total Mixed Ration based diet with different feed mixture composition in trial group (+100 g Algae STM Alltech Inc. per cow and day). Performance data were collected in accordance with official milk recording system of Breeding Services of Slovak Republic s. e. and milk samples were collected once per month according to the A4 standard methodology. The control group showed higher level of milk production compared to trial. Our study indicated that the feeding of algae caused milk fat depression and generally lower protein content in milk. Significant impact of algae feeding was found also for the level of urea in milk. In addition, the supplementary feeding of DHA may represent effective strategy to increase the percentage of pregnancies per inseminations in lactating dairy cows. [ABSTRACT FROM AUTHOR]

The current study was designed to evaluate the effect of different doses of pregnant mare serum gonadotropin (PMSG) on reproductive performance synchronized with prostaglandin F2α (PGF2α) in Chinese Holstein dairy cows. The study was conducted on one hundred cyclic dairy cows. Cows were equally divided into five treatment groups. Each group (n=20) was administered with an injection of PMSG (Serum Gonadotrophin for Injection, SanSheng Pharmaceutical, China) at dose rate of 2, 2.5, 3, 3.5, or 4 IU/kg BW, followed by an injection of PGF2α (Cloprostenol Sodium for Injection, SanSheng Pharmaceutical, China) 48 h later. Estrus was detected by a teaser bull three times daily after PGF2α administration. The cows were artificially inseminated 12 and 20 h after standing heat. On day 30 after artificial insemination, pregnancy rate was confirmed by transrectal ultrasonography while calving rate and multiple calvings were added up after successful parturition. There were no significant difference (P>0.05) in estrus response among all treatment groups. Similarly, interval from PMSG administration to estrus was decreased non-significantly (P>0.05) with the different doses of PMSG. Pregnancy rate was significantly lower (P0.05) among different regimens. The effects of PMSG dose on multiple calving was found to be statistically significant (P2.5 IU/kg) than in the lowest treatment group (2 IU/kg), however, later pregnancy rate was non-significant (P>0.05) in all groups. In summary, PMSG administration could successfully induce estrus and improve fertility of a dairy herd. Furthermore, low doses of PMSG aid in quick return of non-pregnant cows to subsequent next estrus.

Retrospective data from Sebele Dairy Farm were analysed for reproductive performance of Friesian/ Holstein cows. Three hundred records from 1989 to 1995 were used. The herd was zero grazed and the data was analysed for age at first calving (AFC), calf birth weights (BW), calving interval (CI), days open (DO), calving rate (CR), reproductive wastage (RW) and calving difficulty (CD); dystocia, after-birth retention and misrepresentation of foetus) and calving weights (CW). The effects of year of calving (YOC) and year of birth (YOB) were tested. The year of calving affected age at first calving (P<0.05) whereby in 1989/90 and 1990/91 cows were younger than the rest of the years. Calving weight at first calving was significantly affected (P<0.01) by year of calving. YOC had an effect (P<0.05) on both calving interval and days open. CW and CR were significantly affected (P<0.001 and more) by the year of calving. Reproductive wastage tended (P=0.065) to be affected by YOC while no effect (P>0.05) was observed for BW and CD. The year of birth of cows (YOB) had an effect (P<0.05) on age at first calving and it also significantly affected (P<0.01) CW of first calving heifers. Heifers born in the 1980's had lower live weight at calving than those born in the 1990's. Age categories (1=20-39 months; 2=40-69 months and 3=>70 months) tended (P=0.062) to influence the birth weights of calves. As cows' age increased, birth weights of their calves decreased. However, age category did not affect (P>0.05) calving interval or days open. Male calves were heavier (P<0.05) at birth than females (38.7±1.3 kg vs. 36.8±0.7 kg). CW was lower for heifers than for cows and represented 84% of the cows' weights. Heifers had higher (P<0.01) CR than cows (100 vs. 64.9%), however RW was higher (P<0.01) for heifers than cows (25.0 vs. 11.0%). RW was significantly correlated with birth difficulty (r=0.50; P<0.001). It seems that a low temperature-humidity index in the month of conception resulted in higher CR nine months later. It is recommended that when cows are zero grazed, feed quality should be assured by nutrient balancing and should not affect performance between years. [ABSTRACT FROM AUTHOR]

Background: Reproductive diseases limit the productivity of cattle worldwide and represent an important obstacle to profitable cattle enterprise. In this study, herd brucellosis and bovine genital campylobacteriosis (BGC) status, and demographic and management variables were determined and related to predicted calving rate (PrCR) of cattle herds in Adamawa, Kaduna and Kano states, Nigeria. Serum samples, preputial scrapings, questionnaire data, trans-rectal palpation and farm records were used from 271 herds. The Rose-Bengal plate test and competitive enzyme-linked immunosorbent assay were used for Brucella serology and culture and identification from preputial samples for BGC. A herd was classified as positive if one or more animals tested positive. The PrCR was determined as the number of calvings expected during the previous 6 and next 6 months as a percentage of the number of postpubertal heifers and cows in the herd. A multilevel linear regression model was used to estimate the herd-level effect of Brucella abortus seropositivity, Campylobacter fetus infection and other factors on calculated PrCR. Results: The reproductive performance of the cattle herds was generally poor: Only 6.5% of the nursing cows were pregnant and 51.1% were non-pregnant and acyclic; the mean annual PrCR was 51.4%. Brucella abortus and C. fetus infection of herds were independently associated with absolute reduction in PrCR of 14.9% and 8.4%, respectively. There was also a strong negative association between within-herd Brucella seroprevalence and PrCR. Presence of small ruminants, animal introduction without quarantine and the presence of handling facilities were associated with lower PrCR, whereas larger herd size, supplementary feeding, routine mineral supplementation and care during parturition were associated with higher PrCR. Conclusions: Brucellosis and BGC may be largely responsible for the poor reproductive performance of indigenous Nigerian cattle. Farmer education and measures to improve the fertility of cattle herds are suggested. [ABSTRACT FROM AUTHOR]

The objectives of this work were to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbred and crossbred cows with Angus and Brahman, to estimate heterosis and direct and maternal genetic breed effects, and to describe calf loss, cow removals from the project, the occurrence of calving difficulty, inadequate calf vigor at birth, and udder problems by cow breed groups. Cows (n = 404) were bom from 2002 to 2005. After their first exposure to bulls as young cows, in all subsequent breeding seasons crossbred cows were bred to bulls of the third breed, and straightbred cows were bred to bulls of the other two breeds. Calving records (n = 1,484) from 2005 to 2011 were used to create calving and weaning rate and calving interval (excluding the interval between 2 and 3 yr of age). Final models for these traits included sire breed-dam breed interaction, cow age within year, and random animal effects. Heterosis estimates for Romosinuano-Brahman calving and weaning rate were 0.06 ± 0.02 and 0.07 ± 0.03 (P < 0.05); those for Brahman-Angus were twice as large (0.13 ± 0.03 and 0.14 ± 0.03, respectively; P < 0.001). Estimates of Brahman direct effects on calving and weaning rate were -0.12 ± 0.04 and -0.14 ± 0.05 (P < 0.05); however, Angus direct effects were beneficial for both traits (0.1 ± 0.05, P < 0.05). The effect of heterosis was to reduce calving interval by -49.2 ± 9.9 and -37.2 ± 9.7 d for Romosinuano-Brahman and Brahman-Angus, respectively (P < 0.001). Romosinuano and Fj cows sired by Romosinuano and out of Angus dams had the most occurrences of difficult births as a proportion of cows that calved (0.028 and 0.025, P = 0.04). Angus-sired crossbred cows and Brahman cows had the most occurrences of udder problems as a proportion of lac-tating cows (0.14 to 0.21, P < 0.04). There were more Brahman-sired cows that died or were culled as a proportion of those cows that began the project (0.1 to 0.28, P < 0.02) than cows in the other breed groups. Romosinuano-Brahman and Romosinuano-Angus cow performance was acceptable, but for most traits, those pairs of breeds had lower heterosis than Brahman-Angus. [ABSTRACT FROM AUTHOR]

Reproductive performance of animals affects lifetime productivity. However, improvement of reproductive traits via direct selection is generally slow due to low heritability. Therefore, identification of indicator traits for reproductive performance may enhance genetic response. Previous studies showed that serum IGF-I concentration is a candidate indicator for growth and reproductive traits. The objective of our study was to estimate the variances or covariances of IGF-I concentration with reproductive traits. Data were collected from a divergent selection experiment for serum IGF-I concentration at the Eastern Agricultural Research Station owned by The Ohio State University. The study included a total of 2,662 calves in the 1989 to 2005 calf crops. Variance or covariance components were estimated for direct and maternal genetic effects, maternal environment effects, environment effects, and phenotypic effects using an animal model in a multiple-trait, derivativefree, restricted maximum likelihood (MTDFREML, Boldman et al, 1995) computer program. Direct additive genetic correlations suggest that selection for greater IGF-I concentration (heritability = 0.50 ± 0.07) could lead to increased conception rate (heritability = 0.11 ± 0.06, r = 0.32, P < 0.001) and calving rate (heritability = 0.13 ± 0.06, r = 0.43, P < 0.001) and decreased age at first calving in heifers (heritability = 0.35 ± 0.20, r = -0.40, P < 0.001). [ABSTRACT FROM AUTHOR]

A review of the smallholder dairy production in Malawi was conducted using livestock annual reports and other literature that was supplemented with primary data from a baseline survey conducted in December 2009. Smallholder dairy farming in Malawi operates with support from institutions that facilitate access to initial stock and dairy production technologies. Most farmers (94%) keep the animals in pens where feed is provided throughout the year. Results indicated unsatisfactory feeding, housing and health management practices, which negatively impact cow fertility. Dairy population trends suggest low replacement rates, which could be associated to low cow fertility and inadequate management skills. There are challenges related to access to breeding and health services, which further contribute to low productivity. Low fertility is evidenced by low calving rates (22-61%) and long calving interval (405-549 days). Existence of programmes on farmer capacity building provides an opportunity for improved management skills and cow productivity. It is concluded that dairy cow management and fertility have challenges and opportunities that are influenced by the extent to which farmers have access to important services such as extension, health, breeding and finance. [ABSTRACT FROM AUTHOR]

Objective. Modeling lactation curves for milk yield and for fat (%) and protein (%) and to determine the main factors affecting the lactation curve. Materials and methods. Official milk control data of 1532 Holstein dairy cows from 19 farms from the department of Antioquia, Colombia were used. Non-linear mathematical models proposed by Wood, Brody, Papajcsik and Bodero and Wilmink were calculated. Regression coefficients of the best fit non linear model selected was used for the effect on parity, time and year of birth was. Results. Lactation curves for milk yield and both fat and protein percentages estimated by Wood's model showed the best values for the comparison criteria used. Parity and year of parity effects were significant for the estimated parameters in the Wood's model. Conclusions. Wood's model showed the best fit in lactation curves for milk yield and for fat (%) and protein (%). The lactation curve for protein (%) was characterized by a very consistent production and no major fluctuations throughout lactation. [ABSTRACT FROM AUTHOR]

Multiparous beef cows were managed to achieve marginal (BCS = 4.7 ± 0.07; n = 106) or good (BCS = 6.6 ± 0.06; n = 121) body condition (BC) to determine the influence of forage environment on BW and BC changes, intramuscular fat percentage (IMF), rump fat (RF), and serum hormones during 2 yr. Cows within each BC were randomly assigned to graze either common bermudagrass (CB; n = 3 pastures/yr) or toxic endophyte-infected tall fescue (EI; n = 3 pastures/yr) during a 60-d breeding season. Blood samples were collected at d 0, 30, and 60 of the breeding season, and serum concentrations of prolactin (PRL), IGF-I, and cortisol (CORT) were quantified; PRL and progesterone (P4) also were quantified 10 d before the breeding season (d -10). Body weight and BCS were recorded during the breeding season (d 0, 30, and 60). Cow IMF and RF were measured via ultrasonography at the start and end of the breeding season. Cows with increased (>1 ng/mL) P4 at the beginning of the breeding season (cyclic) had greater (P < 0.02) concentrations of PRL on d 30 and 60 compared with anestrous cows. A forage environment × BC interaction tended (P = 0.07) to influence PRL. Cows grazing CB independent of BC had increased PRL compared with cows grazing EI. Prolactin was decreased in good-BC cows grazing El compared with cows grazing CB, and cows in marginal BC grazing El had the least concentrations of PRL. Concentrations of IGF-I were similar (P > 0.10) among good- and marginal-BC cows grazing CB, as well as good-BC cows grazing El; however, marginal-BC cows grazing El had reduced (P < 0.04) concentrations of IGF-I compared with all other groups. Cows in marginal BC grazing CB gained (P = 0.02) the most BW during the breeding season, whereas good-BC cows grazing El gained the least amount of BW. Marginal-BC cows grazing CB tended (P 0.06) to increase BC during the breeding season, whereas good-BC cows grazing either CB or El lost BC. Rump fat tended (P = 0.07) to increase during the breeding season in marginal-BC cows compared with cows in good BC. Calving rates were similar (P > 0.10) among good- (82%) and marginal- (84%) BC cows grazing CB, and good-BC cows grazing El (79%); however, marginal-BC cows grazing El had a reduced (P = 0.04) calving rate (61%). Cattle grazing El during the breeding season lost BC. That reduction in BC maybe communicated to the pituitary via hormones that include IGF-I or PRL or both, resulting in decreased calving rates. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we developed a defined culture medium that supported improved in vitro bovine embryo development and calving rate after embryo transfer (ET). In vitro-matured bovine oocytes from abbatoir-derived ovaries from Korean native, HanWoo cattle were fertilized with frozen–thawed spermatozoa and embryos were cultured in two-step culture media. In Experiment 1, embryos were cultured in media supplemented with 8mg/mL BSA, or 0.1mg/mL PVA and 8mg/mL BSA+2.77mM myo-inositol or 0.1mg/mL PVA+2.77mM myo-inositol. Although defined culture media containing PVA supported lower developmental competence compared to undefined media (containing BSA; 8% versus 34%, respectively), defined culture media containing 2.77mM myo-inositol increased rates of blastocyst formation up to 28%. In Experiment 2, the effect of energy substrate (1.5mM glucose or 1.2mM phosphate) in PVA–myo-inositol defined culture medium on in vitro embryo development was investigated. Defined culture media containing PVA, myo-inositol and phosphate supported better embryo development to blastocysts compared to medium supplemented with both glucose and phosphate (43% versus 31%). In Experiment 3, the effect of epidermal growth factor (EGF) in PVA+myo-inositol–phosphate two-step culture medium on in vitro embryo development was investigated. Among 0, 1, 10 and 100ng/mL EGF concentrations, the maximal effect was observed with 10ng/mL EGF (52% blastocyst formation). In Experiment 4, total cell number and calving rate were compared between defined PVA–myo-inositol–phosphate–EGF medium and undefined medium containing BSA, glucose and phosphate. No differences in total cell number of blastocysts obtained from the two groups were observed, however, the rate of viable offspring production was increased using the defined culture medium, compared to the undefined culture medium. In Experiment 5, the relative abundance of mRNA transcripts [interferon-tau (If-τ), glucose transporter-1 (glut-1) and insulin like growth factor 2 receptor (Igf2r)] were analyzed in blastocysts derived from undefined or defined culture media. Gene expression of If-τ, glut-1 was significantly increased in defined culture medium compared to undefined medium. In conclusion, chemically defined culture media without BSA or FBS improved developmental competence of in vitro cultured bovine embryos and delivery of viable calves after ET. [Copyright &y& Elsevier]

To determine the maternal and reproductive performance of F1 cows in the subtropics, 42 Brahman × Angus, 34 Senepol × Angus, and 50 Tuli × Angus cows were bred to Angus bulls to calve first and subsequently bred to Charolais bulls to calve as 3- to 8-yr-olds. Age at first calving did not differ among crossbred cows. Angus-sired calf birth weights were heavier (P<0.01) from Senepol × Angus than either Brahman × Angus or Tuli × Angus cows. Weaning weights of Angus-sired calves were heavier (P<0.01) from Brahman × Angus (213.5 kg) than either Senepol × Angus (194.9 kg) or Tuli × Angus (191.5 kg) cows. As 3- to 8-yr-old cows, calf birth weights were heavier (P<0.05) from Senepol × Angus compared with Brahman × Angus but not Tuli × Angus cows. Weaning weights of Charolais-sired calves were heaviest (P<0.05) from Brahman × Angus cows (268.9 kg), lightest from Tuli × Angus cows (233.4 kg), and intermediate from Senepol × Angus cows (245.0 kg). Calf crop born and calf crop weaned were lowest (P < 0.05) for Senepol × Angus cows (76.9 and 70.2%) and did not differ between Brahman × Angus (89.0 and 86.1%) and Tuli × Angus (94.7 and 86.5%) cows. Tuli × Angus cows tended (P < 0.10) to have a lower percentage of unassisted births and lower (P < 0.10) calf survival to weaning than Brahman × Angus cows but not Senepol × Angus cows. As 3- to 8-yr-olds, weaning weight per cow exposed was greatest (P<0.05) for Brahman × Angus (234.2 kg), least (P<0.05) for Senepol × Angus (173.0 kg), and intermediate (P<0.05) for Tuli × Angus (209.1 kg) cows. Also as 3- to 8-yr-olds, efficiency (205-d calf weight per 100 kg of cow exposed) was similar for Brahman × Angus (42.2) and Tuli × Angus cows (40.7), and both were greater (P < 0.01) than for Senepol × Angus cows (33.8). These data indicate that, in the subtropics, maternal and reproductive performance of Tuli × Angus cows, but not Senepol × Angus cows, was comparable to Brahman × Angus cows, except for lower calf survivability and weaning weight. [ABSTRACT FROM AUTHOR]