Inter-calving Interval Research Articles

Effect of prostaglandin treatment on the estrus behaviour, follicular and luteal morphometry and serum hormone profile in sub-estrus buffaloes during non-breeding season.

Sub-estrus buffaloes do not exhibit estrus signs despite being cyclic contributing to extended service periods and inter-calving intervals causing significant economic loss. The present study described the effect of synthetic prostaglandin (PGF2α) on estrus behaviour, follicular and luteal morphometry, and serum estradiol (E2) and progesterone (P4) profile in sub-estrus buffaloes during the non-breeding season. The incidence of sub-estrus was 38.4% during the non-breeding season. The sub-estrus buffaloes (n = 33) were divided into two groups, viz., Control (n = 16) and PGF2α treatment (Inj. Cloprostenol 500 μg, i.m., n = 17). Estrus induction response was significantly greater in the treatment (100 vs. 18.75%, p < .001), and a relatively greater proportion of animals conceived in the treatment group (29.41 vs. 6.25%, p = .08). The time elapsed to induction of estrus and insemination following treatment was significantly lower in the treatment group than control. A significant increment in the follicle diameter (9.72 ± 0.45 vs. 13.00 ± 0.45 mm, P < .0001) and serum estradiol (E2) concentration (66.01 ± 11.92 vs. 104.9 ± 13.21 pg/mL, p = .003) observed at the post-treatment period in the PGF2α treatment group. At the same time, CL diameter was reduced significantly at a higher regression rate in the PGF2α treated buffaloes than those of control. Of the responded buffaloes, only 30% showed high-intensity estrus attributed to the expulsion of cervico-vaginal mucus (CVM), uterine tonicity, micturition, and mounting response by a teaser bull. From this study, it can be concluded that the administration of PGF2α could induce estrus in the sub-estrus buffaloes during the non-breeding season. Behavioural changes, along with sonographic observation of POF, regressing CL, and serum E2 and P4 concentration would be useful to determine the right time of insemination in sub-estrus buffaloes during non-breeding season.

Association of Mycobacterium avium paratuberculosis serostatus with age at first calving, calving interval, and milk production in dairy cows

Mycobacterium avium ssp. paratuberculosis (MAP) is the causative agent of bovine paratuberculosis, also known as Johne's disease. This infection is responsible for negative effects, ranging from reduction of milk production to reproductive compromise and increased susceptibility to other diseases such as mastitis. Contradictory information on the association between this infection and reproductive performance has been reported in dairy cows. The aim of this work was to investigate associations between individual cow MAP seropositivity and lifetime reproduction and production performance. The MAP serum ELISA (IDEXX MAP Ac) results from all the 13,071 adult cows present on 191 farms and corresponding birth- and calving-date records obtained from the National Association for Genetic Improvement of Dairy Cattle were used. Cows and farms were classified as positive or negative, based on ELISA results. Outcomes assessed were age at first calving (AFC), intercalving intervals (ICI) from first to fourth interval, and average milk production per day of productive cycle (Milk-305/ICI, a ratio between 305-d corrected milk production and the number of days of the respective calving interval). Multilevel mixed models were used to investigate the association of cow MAP status with AFC, ICI, and Milk-305/ICI. Three levels were considered in the models: "measurement occasion," the first level, was nested within cows and cows were nested within farms. The "measurement occasion" is the time point to which all the observed measures (between 2 successive parturitions, such as milk production and somatic cell count) were referred. Our results indicate that MAP-positive cows have a significantly lower 14-d mean AFC than MAP-negative cows. The overall average ICI in our study was 432.5 d (standard deviation: 94.6). The average ICI, from first to fourth, was not significantly affected by MAP seropositivity. No significant effect of MAP positivity was found on the overall ICI. In relation to Milk-305/ICI, MAP-positive cows did not produce significantly less milk than negative cows across their productive lifetime. We observed higher but nonsignificant Milk-305/ICI (kg/d) in MAP-positive cows. In our study, the proportion of MAP-positive cows within lactations remained similar across all lactations, suggesting that seropositivity did not increased drop-off rate.

Lactation traits and reproductive performances of Sahraoui female camel in two breeding systems at Algerian Sahara.

The main objective of this study is to determine the impact of the camel livestock system on individual and herd performances of milk production, lactation curve, fats, and protein concentrations. For this purpose, 13 she-camels of Sahraoui breed from the south eastern Algeria and belonging and semi-intensive system (N = 6) and intensive system (N = 7) were studied. Recording and sampling of milk were carried out at regular intervals during a full lactation. The lactation curve was estimated using Wood's gamma function and the t-test of independent groups was carried out to compare lactation performances, lactation curve, and reproductive parameters. The overall average daily milk (DMY), fat (DFY), and protein (DPY) yield were 6.77 ± 0.82kg/day, 4.15 ± 0.91%, and 4.49 ± 0.20%, respectively. The mean of total milk yield (TMY) was 2696.39 ± 343.86kg during a mean lactation length (LL) of 398.38 ± 20.65days. The peak of milk production (6.79 ± 0.68kg) was reached at 93.9 ± 55.8days after calving. The open day (DO) and inter-calving interval (ICI) recorded in this study were 348.38 ± 30.33 and 723.38 ± 30.33days, respectively. There is no significant difference (p > 0.05) between intensive and semi-intensive breeding systems for TMY (2795.39 ± 261.88kg vs. 2580.89 ± 414.43kg), DMY (6.96 ± 0.66kg vs. 6.55 ± 1.00kg), and LL (402.14 ± 21.18days vs. 394 ± 21.03days). However, the total amount of fat was significantly higher in intensive system (182.02 ± 33.91kg) and the DPY content was significantly higher in semi-intensive system (4.60 ± 0.13%). The parameters α, β, and γ of lactation, fat, and protein curves between the two systems showed a highly significant difference (p < 0.01) for the parameters (α and β) for the milk production curve, significant (p < 0.05) for the time to reach peak yield, and no significance for the other parameters. The corresponding values of the coefficient of determination (R2) were 0.62, 0.35 for milk yield (p > 0.05), 0.12, 0.13 (p > 0.05) for fat, and 0.03, 0.11 (p < 0.05) for protein, in the intensive and semi-intensive systems, respectively. In addition, DO and ICI were not significantly different between the livestock systems, but were higher in the intensive system than the semi-intensive system (337.17 ± 26.26 vs. 712.17 ± 26.26, respectively). The study concluded that the intensive system had a higher milk performance with a more efficient lactation curve. The incomplete gamma model (Wood) used in this study was inappropriate for estimating milk yield, but acceptable for fat and protein.

Genome-wide association study of age at puberty and its (co)variances with fertility and stature in growing and lactating Holstein-Friesian dairy cattle

Reproductive performance is a key determinant of cow longevity in a pasture-based, seasonal dairy system. Unfortunately, direct fertility phenotypes such as inter-calving interval or pregnancy rate tend to have low heritabilities and occur relatively late in an animal's life. In contrast, age at puberty (AGEP) is a moderately heritable, early-in-life trait, that may be estimated using an animal's age at first measured elevation in blood plasma progesterone (AGEP4) concentrations. Understanding the genetic architecture of AGEP4 in addition to genetic relationships between AGEP4 and fertility traits in lactating cows is important, as is its relationship with body size in the growing animal. Thus, the objectives of this research were 3-fold. First, to estimate the genetic and phenotypic (co)variances between AGEP4 and subsequent fertility during first and second lactations. Second, to quantify the associations between AGEP4 and height, length, and body weight (BW) measured when animals were around 11 mo old (SD = 0.5). Third, to identify genomic regions that are likely to be associated with variation in AGEP4. We measured AGEP4, height, length, and BW in around 5,000 Holstein-Friesian or Holstein-Friesian x Jersey crossbred yearling heifers, across 54 pasture-based herds managed in seasonal calving farm systems. We also obtained calving rate (CR42: success or failure to calve within the first 42 d of the seasonal calving period), breeding rate (PB21: success or failure to be presented for breeding within the first 21 d of the seasonal breeding period) and pregnancy rate (PR42: success or failure to become pregnant within the first 42 d of the seasonal breeding period) phenotypes from their first and second lactations. The animals were genotyped using the Weatherby's Versa 50K SNP array (Illumina, USA). The estimated heritabilities of AGEP4, height, length, and BW were 0.34 (0.30, 0.37), 0.28 (0.25, 0.31), 0.21 (0.18, 0.23), and 0.33 (0.30, 0.36), respectively. In contrast, the heritabilities of CR42, PB21 and PR42 were all < 0.05 in both first and second lactations. The genetic correlations between AGEP4 and these fertility traits were generally moderate ranging from 0.11 to 0.60, whereas genetic correlations between AGEP4 and yearling body conformation traits ranged from 0.02 to 0.28. Our genome wide association study (GWAS) highlighted a genomic window on chromosome 5 that was strongly associated with variation in AGEP4. We also identified 4 regions, located on chromosomes 14, 6, 1 and 11 (in order of decreasing importance), that exhibited suggestive associations with AGEP4. Our results show that AGEP4 is a reasonable predictor of estimated breeding values (EBVs) for fertility traits in lactating cows. While the GWAS provided insights into genetic mechanisms underpinning AGEP4, further work is required to test genomic predictions of fertility that use this information.

Relationship of Body Condition Score at Calving with Reproductive Performance, some Blood Metabolites and some Pathological Conditions in Holstein Cows

The study was conducted at The Great Diwaniyah cows station, located at the southern entrance of Al-Dagarah district - Al-Diwaniyah Governorate, from 6/12/2021 to 25/2/2023, to examine the relationship between body condition score (BCS) and reproductive traits, blood biomarkers, and metabolic diseases in Iraqi Holstein-Friesian cows. The 50 cows in parity2 were divided by body condition at calving into three groups (BCS1 = 2.5-3 point (17 cows), BCS2 = 3-4 point (20 cows), and BCS3 = 4 -5 point (13 cows)) based on 1-5 point scal. They were milked twice a day, morning and evening, by an automatic milking machine. The study found a substantial decrease (P≤0.01) in days open for BCS1 (77.18 days) compared to BCS2 (84.05 days) and BCS3 (88.23 days). The BCS2 group had considerably fewer days available (P≤0.01). Compared to BCS3. The study found a significant decrease (P≤0.01) in inter-calving interval for BCS1 group (354.59 days) compared to BCS2 and BCS3 groups (360.95 and 365.69 days, respectively). BCS2 group showed considerably shorter duration (P≤0.01) compared to BCS3 group. The study found no significant influence on inseminations per pregnancy or pregnancy length in the three cow groups. The study found that the BCS2 group had significantly higher glucose concentration (62.19 mg/100 ml) post-calving compared to BCS3 group (57.86 mg/100 ml), but BCS1 group did not differ significantly (59.30 mg/100 ml). The study found a substantial rise (P≤0.01) in BHB concentration (0.922 mmol/L) in the BCS3 group compared to BCS2 and BCS1 (0.743 and 0.674 mmol/L, respectively). BCS3 group showed a substantial increase (P≤0.01) in NEFA concentration (0.590 mmol/L) compared to BCS2 and BCS1 groups (0.476 and 0.461 mmol/L, respectively). During peak production, BCS2 group had a significant increase (P≤0.05) in glucose concentration (64.04 mg/100 ml) compared to BCS3 group (58.97 mg/100 ml), while BCS1 group did not differ significantly (60.97 mg/100 ml). BCS3 group showed a substantial increase (P≤0.01) in BHB concentration (0.434 mmol/L) compared to BCS2 and BCS1 groups (0.297 and 0.318 mmol/L, respectively). The study found a substantial increase (P≤0.01) in NEFA concentration in the BCS3 group (0.290 mmol/L) compared to BCS2 and BCS1 (0.205 and 0.215 mmol/L, respectively). The study found a significant (P≤0.05) increase in ketosis in Holstein cows with BCS2 and BCS3 groups, with rates of 1 (5.0%) and 2 (15.38%), respectively, compared to the BCS1 group with no injury. No significant changes were seen in placental retention, metritis, mastitis, and neonatal mortality between cows. According to the study, bodily condition during calving is linked to reproductive features, blood metabolites, and disease infection in cows.

Observations on the first Inter-Calving Interval for six, particularly early breeding female white rhinos at Ziwa Rhino Sanctuary, Uganda

Observations on the first Inter-Calving Interval for six, particularly early breeding female white rhinos at Ziwa Rhino Sanctuary, Uganda

Description of cattle production systems in different agro-ecological zones of Narok County, Kenya

Cattle farming is an integral part of the livelihoods of farmers in Narok County. However, very few studies have been conducted to describe livestock production in different agroecosystems in Kenya. The objective of this study was to determine cattle production systems and characteristics under different agro-ecosystems. The study was conducted through the administration of semi-structured questionnaires to 817 farmers in three sublocations from Narok south sub-county. The main livestock production systems were pure pastoral, communal grazing and zero-grazing where indigenous cattle were the predominant breed kept (86.8%) with a few farmers keeping crossbreeds or exotic breeds. However, sheep (75.1%) goats (79.4%), chicken (68.6%) and donkeys (32.9%) were also kept. The mean lactation period for cattle was 9.5 months with average inter-calving interval of 14.1 months. More households (45.1%) grazed cattle within their own pastureland compared to pure pastoralism (12.5%), communal grazing (8.0%), zero grazing (0.9%), or combination (33.5%). Approximately 37.1% of the respondents herded their cattle, 13.1% were on free grazing, 36.6% both free grazing and herding whereas 13.2% used paddocks. The mean land area under pasture was estimated at 53.9 acres. The main source of drinking water was within the grazing field (63.6%) with 36.4% having had to take livestock elsewhere. Most households (85.7%) practicing mixed farming could easily access veterinary services compared to 57.2% and 55.1% in agro-pastoral and pure pastoral system respectively (p&lt;0.0001). The main veterinary interventions were deworming, vaccination, and antibiotic administration. Most households (98.6%) had sprayed their livestock with 98.9% sourcing the products from agrovet outlets. More respondents (63.8%) in agro-pastoral compared to 61.5% and 49.7% from pastoral and mixed farming respectively were aware of East Coast Fever disease (p&lt;0.0001). Cattle were principally fed on natural pasture either produced from owned or leased lands with farmers getting unequal access to veterinary services.

Estimates of dairy herd health indicators of mastitis, ketosis, inter-calving interval, and fresh cow replacement in the Piedmont region, Italy

Test-day milk analysis has largely been used to study health and performance parameters in dairy cows. In this study, we estimated four health indicators of dairy cows using test-day data. Our purpose was to estimate (1) mastitis incidence rate, prevalence, and the probability of recovery; (2) the incidence proportion of ketosis; (3) the duration of inter-calving interval; and (4) the risk of a fresh cow being replaced, in a large cohort of dairy herds in the Piedmont region (Italy).We retrospectively analysed test day records of 261,121 lactating cows and 1315 herds during five years (2015–2020). Mastitis was defined by somatic cell count and ketosis by fat-to-protein ratio. Calving dates were used to calculate ICI and to estimate the removal of a fresh cow from the herd. Mixed-effect generalized linear models were used to adjust for unmeasured herd-level risk factors.The risk of mastitis increased by 120% with parity (Odds ratio [OR] = 2.20, confidence interval [CI]: 2.17 – 2.23), by 7% by months in milking (OR = 1.07, CI: 1.07 – 1.07), and even more if the cow was already affected during the same lactation (OR = 8.74, CI: 8.67 – 8.82). Lactose concentration on the previous test day was the best positive prognostic factor for mastitis recovery (OR = 1.12, CI: 1.08 – 1.17). Ketosis risk was the highest between 3rd and 4th lactations and itself increased the risk of having ICI longer than 440 days (OR = 1.12, CI: 1.02 – 1.22), and fresh-cow removal (OR = 1.75, CI: 1.58 – 1.93). Also, the removal of fresh cows was more likely when mastitis (OR = 1.31, CI: 1.19 – 1.45) or long ICI (OR = 1.34, CI: 1.22 – 1.48) occurred. For each health indicator, herd-level risk factors had an important role (18–56% of within-herd covariance).Our results indicate that milk analysis could be also useful for predicting mastitis, its cure rate, and ketosis. Cow-level risk factors are not enough to explain the risk of these issues. By studying a large population over a long period, this study provides an updated estimate of dairy cow health indicators in Piedmont (north-western Italy), useful for benchmarking dairy herds.

Non-invasive assessment of ovarian activity in free-ranging eastern black rhinoceros (Diceros bicornis michaeli) in Kenya

Eastern black rhinos (Diceros bicornis michaeli) are a critically endangered species living in diverse habitats across Africa. In Kenya, once threatened with extinction due to massive poaching pressures, increased protection has resulted in losses being less than 1% annually today. Still, some populations have failed to achieve desired population growth targets. At Ol Jogi Wildlife Conservancy, some individuals are experiencing sub-optimal reproduction based on historical calving records and long inter-calving intervals (>3years). Hormones drive the reproductive process, so non-invasive assessments of endocrine patterns can be useful indicators of individual reproductive health. In this study, we analysed longitudinal fecal progestagen metabolite (fPM) concentrations in all breeding female eastern black rhinos at Ol Jogi (n = 17) and compared the prevalence of irregular estrous cycles (longer or shorter than 20-40days) and anestrous periods (interluteal period more than twice the length of a normal follicular phase, i.e. > 10days) between optimal (inter-calving interval < 3years) and sub-optimal (>3years) reproducing individuals. Ten rhinos were pregnant during at least part of the study period. A total of 12 complete cycles were observed in seven females with an average length of 36 ± 3days and equal numbers of regular and irregular cycles. Single anestrous periods averaging 67 ± 13days were observed in five females. Surprisingly, a majority of cycles in optimal reproducing individuals were categorized as irregular based on fPM profiles. Overall, results suggest that irregular ovarian activity and isolated bouts of anestrus do not have negative impacts on reproductive performance in this subpopulation at Ol Jogi. A high priority is to continue using noninvasive hormone monitoring to evaluate how ecological or other variables influence reproductive success in this and other eastern black rhino subpopulations in Kenya.

The prevalence, antimicrobial sensitivity, and factors associated with camel mastitis in Isiolo County, Kenya.

The one-humped camels (Camelus dromedarius) adapt very well to arid and semi-arid (ASALs) environments and continue to thrive and produce milk even during severe droughts when cattle, sheep, and goats experience high mortalities. These attributes make the dromedaries very vital for the survival of pastoralists, especially in the ASALs of Africa. Mastitis is among the most important diseases of camels and can cause significant economic losses, thereby endangering the livelihoods of pastoralists. This study aimed to estimate the prevalence, risk factors, and antimicrobial sensitivity of mastitis-causing pathogens in lactating camels in Isiolo County, Kenya. This was a cross-sectional study conducted in July and August 2021. A questionnaire was administered to the camel keepers to capture data on herd-level factors. Lactating camels were then examined for any visible signs of clinical mastitis and as well as to capture data on other animal-level factors such as age, weight, and body condition score. A composite milk sample was collected aseptically from randomly selected camels in a herd. The samples were initially tested for somatic cell counts (SCC) using Somatos mini® automatic cell counter. Culture and sensitivity testing was then carried out on any milk sample that had SCC ≥ 200,000 cells/mL. The descriptive analysis was initially used to summarize the continuous and categorical farm and camel factors, while mixed regression models were used to explore the association between/across mastitis and the farm as well as camel-level factors. A total of 210 lactating camels from 23 herds were selected and sampled in this study. The average age of camel keepers was 48.3 ± 16.3 years and they were involved in rearing camels for a mean of about 14.3 ± 8.6 years. The total number of camels in a herd ranged from 10 to 287, with the mean total herd milk production being 34.5 ± 24.9 L/day. The mean daily milk production per camel was 2.8 ± 1.7 L while the range for days in milk was between 21 and 787 days. The average age of camel first calving and the inter-calving interval was 56.3 ± 9.9 and 27.7 ± 9.9 months, respectively. The median parity of the dam was three and the body condition score was two. About 39.7% (83/210) of the sampled camels had clinical mastitis during the current lactation. The overall prevalence of mastitis (SCC ≥ 200,000 cells/mL) in camels was 17.6%. The main pathogens isolated were Streptococcus and Staphylococcus bacteria. Streptococcus isolates were mainly sensitive to ampicillin and resistant to cefaclor. All 18 Staphylococcus isolates were sensitive to tetracycline, while 12/18 isolates were resistant to ampicillin. The factors that were significantly associated with mastitis were the age of the respondent (p = 0.038), the number of years involved in camel rearing (p = 0.024), presence of clinical mastitis since calving (p = 0.039), body condition score (p = 0.040), and age of the dam at the time of examination (p = 0.072). Results from this study revealed that mastitis is an important condition among camels in the pastoral communities of Isiolo County, Kenya. Thus, pastoralists should continue to be aware of and trained on mastitis occurrence and its control in the pastoral ecosystem to reduce potential economic losses.

Reproduction and Fertility of Buffaloes in Nepal.

Water buffalo (Bubalus bubalis) in Nepal contributes 57% of the total milk and 36% of the total meat production in the country. The productive efficiency of Nepalese buffaloes is quite low, due mainly to subfertility and infertility. Delayed puberty and prolonged inter-calving intervals, attributed mainly by anestrus due to silent cyclicity and ovarian acyclicity, are the major forms of infertility in Nepalese buffaloes. Moreover, buffaloes in Nepal show a distinct seasonal breeding pattern, with July to December as the active breeding season, and with April to June and January to March as the low and transitional breeding seasons, respectively. Endoparasitic infection and poor nutritional status, which are more severe during the low season, are found to be the major factors causing anestrus and compromising its treatment response in buffaloes. Various hormonal protocols for timed artificial insemination (TAI) have been attempted, with a varying pregnancy outcome. Recently, an integrated technique including anthelmintic treatment, nutritional supplementation and hormone-based fertility management programs for TAI has been developed and implemented successfully. A wider adoption of this technique as a package of practices could be key to improving the reproductive efficiency of buffaloes in Nepal.

Husbandry practice, health, productive and reproductive status of lulu cattle in Mustang, Nepal

Lulu is the only indigenous cattle of taurine (Bos taurus) breed that is reared in northern part of central to western Nepal. There have been no recent studies on husbandry practice, health status, productive and reproductive performance of Lulu cattle in Nepal. Therefore, this study was conducted to know the husbandry practice, health, productive and reproductive status of Lulu cattle in Mustang district. Household survey was conducted in Lulu cattle rearing households (n=183) in Mustang; fecal sample of Lulu cow was collected from each household and examined for endoparasitic infection. Body condition score (BCS), hair coat, anemic and milk production status were recorded only from lactating cows (n=242). All of the respondents kept their cows in loose housing system. Among them, 90.2% grazed their cattle, 21.3% provided some cultivated pastures, 3.3% supplemented commercial feed and none of the farmers fed mineral supplementation to their cattle. All the milk produced was used only for home consumption. Only 22% of respondents dewormed their cattle regularly and 29% never dewormed; only 12% vaccinated against foot and mouth disease (FMD) every year and 25% never vaccinated. Cattle of 79.8% households had endoparasitic infection. Among 242 lactating cows, 13.2% cows had poor BCS (&lt;2.75), 95.5% had rough hair coat and 20.4% had anemic (pale) eye mucous membrane. Total 8.3% cows had the history of abortion. Mean (±SD) peak milk yield and lactation length were 2.01±0.30 liter/day and 9.84±0.86 months, respectively. Most of the cows calved in summer (72%) followed by autumn (12%), spring (11%) and winter (5%). Mean (±SD) age of first calving, calving to conception interval, inter-calving interval, dry period and the number of services per conception were 36.0±0.48 months, 3.99±0.68 months, 12.97±1.34 months, 2.71±0.45 months, and 1.47±0.77, respectively. In conclusion, Lulu cattle has the potentiality to increase its productive and reproductive performance through improved health and husbandry practices.

An assessment of the medium-term reproductive success of an extralimital white rhinoceros population

The white rhinoceros (Ceratotherium simum) is threatened primarily due to continued poaching for its horns. In South Africa, partly to promote the conservation of the species, white rhinos have been introduced into areas where they did not occur historically (i.e. where they are considered extralimital). Few studies have investigated the conservation contribution of extralimital white rhinos to the overall national herd. We aimed to determine whether the white rhinos introduced to a private game reserve in the Eastern Cape province have been successful from a reproductive perspective. We calculated inter-calving intervals, age at first calving, sex ratios of calves, and recruitment rates for white rhinos at a single site between 1992 and 2019. The average net annual population growth rate for the population was 10%, which is higher than the recommended 5% by the Biodiversity Management Plan for white rhinos. Trends in density-dependent parameters such as age at first calving and inter-calving intervals also indicated that the study population is still well below the density at which ecological constraints may manifest. We demonstrate that an extralimital white rhino population in the Eastern Cape can be successful from a reproductive perspective.

Effects of dehorning on population productivity in four Namibia sub-populations of black rhinoceros (Diceros bicornis bicornis)

The black rhinoceros (rhino) (Diceros bicornis) is critically endangered, with poaching being one of several threats to the species’ survival. Many reserves across several countries, including Namibia, South Africa, and Zimbabwe, now dehorn their rhinos in an attempt to reduce poaching. Historical data collected by the Namibian Ministry of Environment, Forestry, and Tourism and Save the Rhino Trust were used to investigate whether dehorning has an effect on age at first reproduction (AFR), inter-calving interval (ICI), birth sex ratios, calf survival, cause of death, and lifespan. These were assessed in four Namibian sub-populations (hereafter referred to as ‘populations’) of black rhino (denoted A, B, C, and D) which have undergone varying levels of dehorning. No significant difference was found in any of the variables between dehorned and horned individuals. Population was a significant predictor of AFR (LRT = 7.433, p = 0.024) and ICI (LRT = 13.281, p = 0.004), although pairwise comparisons only found populations A and B to be significantly different (AFR: z = −2.736, p = 0.017, ICI: z = −3.705, p = 0.001). Additionally, a significantly higher number of males than females were born in population D (p = 0.021, CI = 0.544, 0.960). The main cause of death across all individuals was poaching, although there was no significant difference in the proportion of rhinos poached between dehorned and horned individuals (X2 = 0.638, p = 0.424, n = 265). No evidence was found to suggest that dehorning has any effect on AFR, ICI, birth sex ratios, calf survival, or lifespan in the black rhino, which is reassuring in the continued use of dehorning as an anti-poaching technique in this species.

Reproductive Steroid Hormone Patterns in Baleen of Two Pregnant Humpback Whales (Megaptera novaeangliae).

Case studies of two pregnant humpback whales whose hormones were analyzed in baleen may illuminate when humpback whales ovulate, gestate, and give birth. These physiological metrics could assist in accurate population growth assessments and conservation of the species. This study shows that baleen hormone analysis can be a useful tool for understanding whale reproductive physiology.

Reproductive and Productive Performance of Crossbred and Terai Cattle in Bardiya District of Nepal

To compare the reproductive and productive performance of exotic crossbreds and indigenous Terai cattle under farmers' management condition, a household survey was carried out in 218 households of Bardiya, Nepal. Total of 262 cows [Jersey cross (n=107), Holstein cross (n=24) and indigenous Terai cattle (n=131)] were considered to determine the production and reproduction parameters. The age at first calving in months was the lowest in Jersey crossbred (27.8±1.8) followed by Holstein cross (29.5±4.0) and Terai cattle (45.7±3) (P&lt;0.05). However, the number of services per conception, calving to conception interval (in months) and inter-calving interval (in months) were shorter in Terai cattle (1.3±0.7, 3.4±1.4 and 12.6±1.9) compared to Jersey cross (1.7±1.3, 4.4±2.2 and 13.5±3.1) and Holstein cross (1.8±0.9, 5.7±2.8 and 14.9±4.7), respectively (P&lt;0.05). Total 6.5% of cattle had a history of reproductive problems; Incidence of repeat breeding tended (P&lt;0.1)) to be higher in Jersey cross (8.4%) and Holstein cross (8.3%) than in Terai cattle (3.0%). Daily peak milk yield (L/day) was significantly lower in Terai cattle (1.7±1.1) than Jersey cross (13.5±3.1) and Holstein cross (14.9±4.7). The lactation length (months) was significantly shorter in Terai cattle than exotic crossbreds. Consequently, the length of dry period (in months) was significantly longer in Terai cattle (5.2±2.1) than in Jersey cross (2.5±0.9) and Holstein cross (2.2±0.7). The reproductive performance parameters in exotic crossbred cows under the farmers' management condition were satisfactory; however, their productivity was low. Thus, the good reproductive traits and variations in productivity of Terai cattle can be utilized in cross breeding programs.

Low Birthweight Beef Bulls Compared with Jersey Bulls Do Not Impact First Lactation and Rebreeding of First-Calving Dairy Heifers—A Case Study in New Zealand

Dairy heifers in New Zealand are typically naturally mated by Jersey bulls to produce low-value non-replacement offspring sold for slaughter a few days after birth. Producing a beef-sired calf from a dairy heifer will increase the value of these calves for beef production but may compromise the subsequent career of the animals, in terms of milk production, rebreeding success, health, or survival of the heifer. This study aimed to determine the impact of low birthweight Angus and Hereford bulls versus breed-average Jersey bulls on the reproduction and production traits of first-calving dairy heifers. The experiment included 304 heifer-calf pairs over 2 years. Calves sired by Angus and Hereford bulls were 3.5–4.4 kg and 3.7–6.8 kg heavier than Jersey-sired calves and had a 4.2% and 9.3% incidence of assistance at birth for normally presented calves over the 2 years, respectively. No normally presented Jersey-sired calves were assisted. There was no difference in body condition score, pre-calving live weight, milk production, pregnancy rate, inter-calving interval, re-calving day, and 21-day re-calving rate of heifers mated to the different breeds of bulls. The results indicate that the Angus and Hereford bulls with low birthweight and high direct calving ease estimated breeding values (EBV) can be used to produce calves of greater value than Jersey-sired calves without impacting dairy heifer production. However, a small increase in assistance at calving could be expected.

Ginsenoside Rb1 Mitigates Escherichia coli Lipopolysaccharide-Induced Endometritis through TLR4-Mediated NF-κB Pathway.

Endometritis is the inflammatory response of the endometrial lining of the uterus and is associated with low conception rates, early embryonic mortality, and prolonged inter-calving intervals, and thus poses huge economic losses to the dairy industry worldwide. Ginsenoside Rb1 (GnRb1) is a natural compound obtained from the roots of Panax ginseng, having several pharmacological and biological properties. However, the anti-inflammatory properties of GnRb1 in lipopolysaccharide (LPS)-challenged endometritis through the TLR4-mediated NF-κB signaling pathway has not yet been researched. This study was planned to evaluate the mechanisms of how GnRb1 rescues LPS-induced endometritis. In the present research, histopathological findings revealed that GnRb1 ameliorated LPS-triggered uterine injury. The ELISA and RT-qPCR assay findings indicated that GnRb1 suppressed the expression level of pro-inflammatory molecules (TNF-α, IL-1β and IL-6) and boosted the level of anti-inflammatory (IL-10) cytokine. Furthermore, the molecular study suggested that GnRb1 attenuated TLR4-mediated NF-κB signaling. The results demonstrated the therapeutic efficacy of GnRb1 in the mouse model of LPS-triggered endometritis via the inhibition of the TLR4-associated NF-κB pathway. Taken together, this study provides a baseline for the protective effect of GnRb1 to treat endometritis in both humans and animals.

Service Sire Effects on Body Condition Score, Milk Production, and Rebreeding of Mixed-Aged Dairy Cows Bred to Angus and Hereford Bulls—A Case Study in New Zealand

Beef-breed bulls are used in dairy herds to produce a calf of greater value for finishing than calves sired by dairy bulls. There is limited research about which beef-breed bulls are most appropriate, and whether any negative impact on cow performance in terms of milk production and rebreeding should be considered. The aim of this case study was to compare the body condition score, milk production, and rebreeding performance of mixed-aged dairy cows bred to a selection of Angus and Hereford beef-breed bulls. Body condition score, post-calving live weight, milk production, rebreeding performance, and survival of 952 mixed-aged dairy cows artificially bred to 65 Angus and Hereford bulls were compared. There was no effect of service sire on post-calving live weight, days in milk, milk production, or inter-calving intervals of mixed-aged cows. Service sire had an effect on the calving day due to differences in gestation length (p &lt; 0.001), although this did not translate into an effect on days in milk. A longer gestation length negatively influenced pregnancy rates, and greater birth weight of the calf negatively influenced survival to rebreeding (p &lt; 0.05), indicating the potential for an effect of service sire. Selection of beef-breed service sires for dairy cows should include emphasis on lighter calves and shorter gestation lengths. The general absence of the service sire effect on the parameters measured in this study indicated that any of the service sires used in this experiment would be appropriate for use over dairy cows.

Effect of Bovine Tuberculosis on Selected Productivity Parameters and Trading in Dairy Cattle Kept Under Intensive Husbandry in Central Ethiopia.

Bovine tuberculosis (BTB) has substantial impact on fertility, milk, and meat productivity in cattle. However, these assumptions are based on outdated data. Recent global studies on the impact of BTB on cattle productivity are scarce and show sometimes inconclusive and/or contradicting results. This pilot study is the first longitudinal study performed in urban upgraded dairy cattle in Ethiopia that are kept under intensive husbandry. We assessed whether BTB has an impact on various animal productivity parameters and animal movement. Animals (N = 890) included in the study were tested for BTB at least once using the comparative intradermal tuberculin test (CIDT). Fertility, mortality, and offtake were assessed in 21 dairy farms where herd follow-ups over 3 years were performed. In addition, an independent abattoir survey was conducted to assess carcass weight and visible TB-like lesions upon meat inspection. Animal movements (purchasing and offtakes) were documented for each farm. The impact of BTB status on the intervals been birth, service, and calving times and the intercalving intervals was analyzed using a Cox proportional hazards model. The hazard ratio associated with BTB-positive animals was smaller than 1 for all fertility parameters, suggesting that BTB status increases the time between events; however, the effect was small and only statistically significant (95% level) for the time between calving and service. Offtakes included a higher percentage of reactor animals (58%) as compared with non-reactor animals (42%) (p = 0.0001). Overall, reactors were eliminated from the farms within 238.6 days after receiving test results, which was 54.9 days faster than for negative animals. The majority of owners purchased animals within their town or its surrounding. Nearly a quarter of reactors were sold directly to other farms. Animals were also sold further away, including other regions, raising the question of disease spread and the need for an animal tracing mechanism. In the abattoir survey, a total of 349 carcasses were weighed, of which 8% showed visible TB-like lesions and 53.6% had fasciolosis. Negative adult bull carcasses were 7.5 kg heavier than reactor bulls.