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Data from Bering-Chukchi-Beaufort Seas bowhead whales (Balaena mysticetus), harvested during 1973–2021 by aboriginal subsistence hunters, were used to estimate reproductive parameters: length at sexual maturity (LSM), age at sexual maturity (ASM), pregnancy rate (PR), and calving interval. Sexual maturity (N = 187 females) was determined from the presence/absence of corpora in the ovaries, or a fetus. Using sampling bias-corrected logistic regression, LSM was estimated at 13.5 m, 95% CI [13.0, 13.8]. There was a downward trend in LSM over time, statistically significant with one method but marginal with another. A growth model translated this estimate to an ASM estimate of 23.5 years, 95% CI [20.4, 26.7]. Pregnancy rate was determined from mature females (N = 125), and from a subset limited to certain autumn-caught whales (n = 37) to reduce bias. The PR was estimated at 0.46 globally, 95% CI [0.36, 0.55] and 0.38 for the autumn sample, 95% CI [0.20, 0.51]. Both estimated PRs are consistent with a 3-year calving interval, because the larger estimate includes two cohorts of pregnant whales harvested in spring, and bowhead whale gestation is longer than 12 months. These analyses represent the most conclusive empirical estimates of ASM, LSM, and PR for this bowhead whale stock from the largest available data sets to date.

The aim of this study was to assess the impact of genotype-environment interaction (GEI) on the manifestation of traits such as age at first calving (AFC), age at first service (AFS), and calving interval (CI) through the application of the reaction norm model in Holstein cattle raised in Paraná state, Brazil. Utilizing data from the milk testing service of the Paraná Association of Holstein Cattle Breeders (APCBRH), this study analyzed records from 179,492 animals undergoing their first, second, and third lactations from the years 2012 to 2022. These animals were part of 513 herds spread across 72 municipalities in Paraná. The environmental gradient was established by normalizing contemporary group solutions, derived from the animal model, with the 305-day-corrected milk yield serving as the dependent variable. Subsequently, reaction norms were determined utilizing a Random Regression Model. Spearman’s correlation was then applied to compare the estimates of breeding values across different environmental gradients for the studied traits. The highest EG (+ 4) indicates the least challenging environments, where animals experience better environmental conditions. Conversely, lower EG (-4) values represent the most challenging environments, where animals endure worse conditions. The only trait that exhibited a moderate heritability magnitude was AFC (0.23) in the least challenging environmental condition. The other traits were classified as having low heritability magnitudes regardless of the evaluated environmental gradient. While minimal evidence was found for the influence of GEI on CI, a clear GEI effect was observed for AFC and AFS across all environmental gradients examined. A reversal in genotype ranking occurred under extreme environmental conditions. The findings suggest that the best-performing genotype under one environmental gradient may not necessarily excel under another. [ABSTRACT FROM AUTHOR]

Understanding reproductive output and success is integral to the conservation and management of threatened species and populations. Little is known about the reproductive parameters of Australian humpback dolphins (Sousa sahulensis), a species subject to cumulative pressures from anthropogenic threats due to their coastal distribution and strong site fidelity. This study assesses several reproductive parameters, including crude birth, recruitment, fecundity, and calf survival rates, in addition to interbirth intervals of Australian humpback dolphins inhabiting the near‐urban embayment of Moreton Bay, Queensland. Between 2014 and 2020, 106 adult females were photographically identified during 222 boat surveys. Of these, 75.5% (n = 80) were observed with calves. Birth seasonality was apparent and coincided with austral autumn and winter months. Interbirth intervals ranged between 1 and >6 years, with an average of 3.1 (SD = 1.1) years if offspring survived. Findings indicate declining fecundity rates (p <.05, M = 0.12, SD = 0.02), relatively low recruitment rates (M = 0.04, SD = 0.01) and calf survival rates to 1 year of age (M = 0.63, SD = 0.15). This study provides a useful baseline that can inform viability assessments and conservation measures, for both this population and others throughout the species range. [ABSTRACT FROM AUTHOR]

Numerous in-depth studies have described the fertility traits, growth performance and milk yield traits of dairy animals, which are considered indicators of welfare, but there are limited studies examining these traits within the framework of cause-effect relationships, especially in buffaloes. The aim of this study was to determine the changes in some milk, growth and fertility traits of Anatolian buffaloes over the years in some dairy farms where the Buffalo Breeding Project in Public Conditions was implemented in Samsun province and, to investigate the effects of first calving age (FCA) and calving interval (CI) on milk and growth traits. The study was conducted in 27 buffalo farms (3295 buffalo cows and 3317 buffalo calves) located in Bafra district, the region with the highest buffalo population in Samsun province, Türkiye. The data was taken from records previously kept within the scope of the relevant project. The data such as growth characteristics [birth weight (BW), 6th and 12th-mo live weight (LW) values of calves born between 2013-2020] and lactation traits of cows [lactation milk yield (LMY) and lactation duration (LD)] and FCA and CI values were analyzed by analysis of variance. The effect of years on LMY of buffalo cows was found to be significant, and significant positive changes were determined from year to year. In addition, the BW, 6th-mo, and 12th-mo LW values of calves also varied from year to year. As the FCA value of buffaloes increased, the BW, 6th-mo, and 12th-mo LW values of calves and LMY of cows increased. Similarly, CI values affected the BW values of calves (P

Simple Summary: Calving interval data by the National Association of Hungarian Holstein Friesian Breeders in Hungary were processed. According to our results the relatively low proportion of genetic variances indicates that the selection of Holstein-Friesian cattle for reproductive traits (such as calving interval) may render low magnitudes and long-term responses. Nevertheless, the economic importance of these traits should not be overlooked. Our results on genetic trends, according to which the average calving interval decreased a little during the examined period, suggest that, despite the relatively low genetic determination, it is possible to achieve some improvement in reproductive traits. Calving interval (CI) data (N = 37,263) from 17,319 cows born 2008–2018 in six herds were assessed. The data were made available by the National Association of Hungarian Holstein Friesian Breeders in Hungary. The effects of some genetic and environmental factors, population genetic parameters, breeding value (BV) of sires, and phenotypic and genetic trends of the CI were estimated. The GLM method was used for studying different effects on the CI. BLUP animal model was used for heritability (h2) and BV estimation. Linear regression analyses were applied for the trend calculation. The mean of the CI was 412.2 ± 2.0 days. The h2 of the CI proved to be low (0.07 ± 0.01 and 0.08 ± 0.01). There were relatively high differences among the sires in the estimated BV. Based on the phenotypic trend calculation, the CI of cows showed decreasing direction by an average of 1.80 days per year (R2 = 0.94; p < 0.01). In the case of genetic trend calculation, the average BV of sires in the CI has decreased −4.94 and −0.31 days per year (R2 = 0.91 and 0.41; p < 0.01). [ABSTRACT FROM AUTHOR]

BACKGROUND: Traditional dairy farms produce low milk. Reproductive performance is very important for their economic viability. "Days open" is one of the reproductive performance measures, including the time between parturition and the next conception of a dairy cow. OBJECTIVES: This study aims to investigate days open and some reproductive characteristics, and examine the effect of these characteristics on days open in traditional dairy farms. METHODS: In this study, a questionnaire was used to collect data from 870 dairy cows belonging to 363 traditional dairy farms. This research was carried out in Miandoab County, in West Azerbaijan province, Iran. To determine the effects of ovarian cyst, dystocia, abortion, and parity of dam on days open, the multiple linear regression analysis in SPSS software was used. RESULTS: In the cows, the mean days open in the last calving was 132.28 days, and the mean insemination for each pregnancy was 2.27 inseminations. Prevalence of dystocia, abortion, and ovarian cysts was 78%, 1.26%, and 1.95%, respectively. The results of Cox regression showed that parity, abortion, ovarian cysts, and dystocia significantly increased days open. The dystocia in the cows was prevalent mostly due to unknown causes and the owner's hasty intervention during the natural parturition process. CONCLUSIONS: Dystocia, parity, abortion, and ovarian cysts have a significant effect on days open in traditional dairy farms. By training livestock farm workers on issues related to the reproductive management of dairy cows and their parturition period, we can expect an improvement in the reproductive performance of traditional dairy farms. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the (co)variance components and genetic parameters for milk yield adjusted to 305d (MY305), calving-to-conception interval (CCI), number of services per conception (NSC) and calving interval (CI) of Honduran Holstein cows, by fitting a bivariate animal model using Maximum Restricted Likelihood procedures. Model included the fixed effects of calving number, the contemporary calving group (farm-season-year of calving and the cow age as covariate). The estimated means and standard deviations for MY, CCI, NSC and CI were, 5098.60 ± 1564.32 kg, 168.27 ± 104.71 days, 2.46 ± 1.69 services, and 448.73 ± 109.16 days, respectively; and their estimated heritabilities were 0.21 ± 0.05, 0.03 ± 0.028, 0.02 ± 0.024 and 0.06 ± 0.04, respectively. The genetic correlations between MY305 and CCI, NSC and CI were positive and antagonist, with values of 0.64 ± 0.52, 0.99 ± 0.56, and 0.32 ± 0.24 respectively. Even though moderate to low heritability was estimated for MY305, systematic selection for milk yield, with a reduction in reproductive efficiency, if considered as the only selection criterion is important to be considered. By including reproductive traits and considering permanent environment effects into the breeding program, might yield a slow, but constant and permanent improvement over time. [ABSTRACT FROM AUTHOR]

Simple Summary: In Bangladesh, buffalo dairy farming is gaining traction for its cost-effectiveness and the nutritional benefits of buffalo milk. This study aims to examine how environmental factors like age, number of past calvings, season of calving, intervals between calvings, and dry periods influence milk yield and lactation patterns. Through monitoring 384 buffaloes from seven populations across different ecological zones, significant impacts of various factors on milk production and reproduction were observed. Findings indicate that such environmental considerations are crucial for enhancing buffalo dairy farming, suggesting that a focus on these aspects could substantially benefit genetic improvement programs. Household buffalo dairy farming is gaining popularity nowadays in Bangladesh because of the outstanding food value of buffalo milk as well as the lower production cost of buffalo compared to cattle. An initiative has recently been taken for the genetic improvement of indigenous dairy buffaloes. The present study was carried out to determine the influence of some environmental factors like age, parity, season of calving, calving interval, dry period on the lactation yield, and lactation curve of indigenous dairy buffaloes of Bangladesh. A total of 384 indigenous dairy buffaloes from the 3rd and 4th parity of seven herds under two different agroecological zones covering four seasons were selected and ear tagged for individual buffalo milk recording. A milk yield of 300 days (MY300d) was calculated following the International Committee for Animal Recording (ICAR) and the data were evaluated using the generalized linear model (GLM). In production traits, the mean of calculated lactation period (CLP), calculated lactation yield (CLY), and milk yield of 300 days (MY300d) of the overall population were 267.28 days, 749.36 kg, and 766.92 kg, respectively, whereas calving interval (CI) and dry period (DP) as reproductive traits were 453.06 days and 185.78 days, respectively. The season of calving, age of buffalo cows, population or herd, agroecological zone, calving interval, and dry period had significant effects on production traits (p < 0.05 to p < 0.001). The season of calving, level of milk production of 300 days, population, and agroecological zone significantly affected the reproduction traits (p < 0.01 to p < 0.001). Parity was found to be non-significant for both types of traits. The average peak yield of test day (TD) milk production was highest at TD4 (4.47 kg, 98th day of lactation). The average MY300d of milk production was the highest in the Lalpur buffalo population (1076.13 kg) and the lowest in the buffalo population of Bhola (592.44 kg). The correlations between milk production traits (CLP, CLY, and MY-300d) and reproduction traits (CI and DP) were highly significant (p < 0.01 to p < 0.001). Positive and high correlation was found within milk traits and reproduction traits, but correlation was negative between milk traits and reproduction traits. Therefore, these non-genetic factors should be considered in the future for any genetic improvement program for indigenous dairy buffaloes in Bangladesh. [ABSTRACT FROM AUTHOR]

A dairy cow in a stable herd will typically have 3.4 lactation numbers, and many dairy farmers do not keep their dairy cows for extended lactation number past the sixth lactation. As a result, there is limited study on the influence of later lactation number or parity (6--10) on lactation traits. In order to determine the effect of lactation number of crossbred Holstein Friesian cows on their calving interval, calves weight, gestation length, lactation milk yield, and number of services per conception, this study was carried out. The record data at the dairy farm operated by Haramaya University was gathered and organized. A retrospective analysis was conducted on the number of services per conception, gestation length, lactation length, lactation milk yield, calving interval, and calf birth weight of dairy cows using records of 1863, 1742, 1280, 1280, 1329, 1170, and 848, respectively. The numbers of lactations per conception and gestation length were not impacted by lactation number, but it did have a significant impact on the total lactation milk yield, lactation length, calving interval, and calf birth weight. According to the findings of this study, crossbred Holstein Friesian cows could continue to produce milk up until their eighth lactation without experiencing a discernible drop in yield. As a result, lactation number ought to be considered a crucial trait in dairy cattle performance. To determine how lactation number affects other lactation traits like dry period, days open, and milk composition, more research needs to be done. [ABSTRACT FROM AUTHOR]

This study aims to compare the reproductive performance of the Ongole cross (PO) and OngoleLimousin cross (Limpo) on smallholder farmer in Bekri district, Central Lampung regency, Lampung province, a Indonesia. This study used 30 PO cows, 30 Limpo F1 (first filial) cows and 30 Limpo F2 cows. Sample cows had at least two parities and had never had a history of reproductive disorders. This study used primary and secondary data related to sample cows. Primary data was obtained from interviews with farmers and secondary data was obtained from the Department of Plantations, Livestock and Fisheries of Central Lampung regency, and inseminator recording. Data were described descriptively and analyzed using a one-way Analysis of Variance in Statistical Product and Service Solution (SPSS) version 23. The result showed that the services per conception of Limpo F2 cows was higher (p <0.05) than for PO and Limpo F1 cows. Days open and calving interval for Limpo cows (F1 and F2) were longer (p <0.05) than for PO cows. Days open and calving interval for Limpo F1 cows were not significantly different (p >0.05) than for Limpo F2 cows. Reproductive performance of PO cows was better compared to Limpo F1 and Limpo F2 cows. However, there was a data discrepancy between reproductive performance and data on rearing systems, feed quality, and signs of estrus observed by farmers. It could be concluded that PO cows had better reproductive performance than Limpo cows. [ABSTRACT FROM AUTHOR]

This study aims to compare the reproductive performance of the Ongole cross (PO) and Ongole-Limousin cross (Limpo) on smallholder farmer in Bekri district, Central Lampung regency, Lampung province, a Indonesia. This study used 30 PO cows, 30 Limpo F1 (first filial) cows and 30 Limpo F2 cows. Sample cows had at least two parities and had never had a history of reproductive disorders. This study used primary and secondary data related to sample cows. Primary data was obtained from interviews with farmers and secondary data was obtained from the Department of Plantations, Livestock and Fisheries of Central Lampung regency, and inseminator recording. Data were described descriptively and analyzed using a one-way Analysis of Variance in Statistical Product and Service Solution (SPSS) version 23. The result showed that the services per conception of Limpo F2 cows was higher (p 0.05) than for Limpo F2 cows. Reproductive performance of PO cows was better compared to Limpo F1 and Limpo F2 cows. However, there was a data discrepancy between reproductive performance and data on rearing systems, feed quality, and signs of estrus observed by farmers. It could be concluded that PO cows had better reproductive performance than Limpo cows.

Dairy production relies predominantly on a few, selectively bred, high-yielding dairy breeds, resulting in a surplus of low-value male offspring. This situation leads to a conflict between a growing demand for milk and low appreciation for dairy calves. Extending lactation could reduce the number of calves born. This study aimed to assess the current use of extended lactation in dairy production in Southern Germany, identify the perceived potential, and determine the biological potential extended lactation has to reduce calf numbers. A survey from 2020 with 310 farmers was analysed. A total of 145 (46.8%) farmers used extended lactation. The use of extended lactation on farms correlated significantly with breed, milk yield, interest in continuing or implementing the use of extended lactation, and the indicated feasibility of extended lactation. The perceived potential was assessed by 39.8% of farmers as “high” to “very high”. A total of 17 (12.8%) farmers currently not using extended lactation were identified as potential adopters. Together with existing adopters, this could result in 52.3% of farms using extended lactation, which could biologically reduce calf numbers by 7.3% or 14.1% p.a., when extended by three or six months, respectively. This adoption potential shows that extended lactation can reduce calf numbers considerably, addressing both ethical and economic concerns in dairy farming and benefiting farmers as well as society.

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The aim of this study was to determine the fertility, herd life and milk yield characteristics of Simmental (SIM) cows of Austrian origin, which have increased the interest of cattle breeders in Türkiye in recent years. From the records of the farm between 2011 and 2021, the first calving age (FCA), calving interval (CI), herd life (HL), productive life (PL), lactation length (LL), lactation milk yield (LMY) and 305 days milk yield (305-dMY) were calculated. A total of 307 FCA, 619 CI, 212 HL and PL, 447 LL, 271 LMY and 497 305-dMY data were used. The means of FCA, CI, HL, PL, LL, LMY and 305-dMY for SIM cows were 842.35±5.30 days (28.1 months), 422.98±3.18 days, 75.48±1.72 months, 47.15±1.73 months, 363.52±3.52 days, 10,596±152 kg and 8647.0±58.0 kg, respectively. Based on the long FCA and CI averages of Austrian-origin SIM cattle, although it can be interpreted that there are some problems in terms of reproductive efficiency in the farm, finding long HL and PL and high milk yield, it can be said that the farm contributes to the increase of milk yield per cow by turning the negativity caused by the reproductive efficiency into an advantage.

Abstract Background Breeding objectives are designed to achieve targeted dairy cow production goals, which can be affected by production type, farmer preferences, environmental factors and genetic factors individually or in combination. Breeding practices, such as both controlled and uncontrolled, and artificial insemination (AI) are the tools used to obtain the desired breeding objectives. The lower reproductive performance of indigenous dairy cows affects the total milk production and calf crops that are produced during their lifetime. Designing appropriate breeding objectives and breeding practices can improve the reproductive performance of dairy cows and their overall production performance. Materials and methods The current study was conducted with the objective of evaluating the breeding, practices and performance of indigenous dairy cattle in the south western part of Ethiopia. The districts of Gesha and Chena were purposefully chosen. The study design for the 384 household surveys was a cross‐sectional survey with a simple random sample approach. Data analysis was carried out by MS‐Excel (2010) and the general linear model procedure of SAS of 2008. Results The current study revealed that methods of breeding were predominantly natural‐controlled mating, followed by natural‐uncontrolled mating and AI in descending order. Breeding objectives were input function, output function, sociocultural and economic functions and assets and security functions in decreasing order of rank. Reproduction performance indexes of indigenous dairy cows age at first service (3.72 ± 0.05 years), age at first calving (AFC) (4.71 ± 0.07 years), calving interval (CI) (1.58 ± 0.03 years), days open (DO) (4.26 ± 0.11 months), services per conception in natural mating (1.4 ± 0.08) and AI (2.73 ± 0.14), age of bull at maturity (4.17 ± 0.74 years), interoestrus interval (23.18 ± 0.61 days), calves crop (7.53 ± 0.22) and the life span of indigenous dairy cow (11.94 ± 0.26 years) were significant (p

Calving interval (CI) data (N = 37,263) from 17,319 cows born 2008–2018 in six herds were assessed. The data were made available by the National Association of Hungarian Holstein Friesian Breeders in Hungary. The effects of some genetic and environmental factors, population genetic parameters, breeding value (BV) of sires, and phenotypic and genetic trends of the CI were estimated. The GLM method was used for studying different effects on the CI. BLUP animal model was used for heritability (h2) and BV estimation. Linear regression analyses were applied for the trend calculation. The mean of the CI was 412.2 ± 2.0 days. The h2 of the CI proved to be low (0.07 ± 0.01 and 0.08 ± 0.01). There were relatively high differences among the sires in the estimated BV. Based on the phenotypic trend calculation, the CI of cows showed decreasing direction by an average of 1.80 days per year (R2 = 0.94; p < 0.01). In the case of genetic trend calculation, the average BV of sires in the CI has decreased −4.94 and −0.31 days per year (R2 = 0.91 and 0.41; p < 0.01).

This research aimed to determine the performance of swamp buffalo reproduction and production at the small-scale holder farmer in Sragen Regency, Central Java, Indonesia, from June to September 2021. The method used in this research was a survey with a census (complete) sample determination. Data collection applies to interviews, observations and literature studies. Research parameters used in reproductive performance were calving interval (CI), service per conception (S/C), age of the first estrus, age of first birth and postpartum estrus. In contrast, production performance parameters were chest circumference, body length and estimated body weight. The result of research on reproductive performance showed that the average CI were 13.2±0.9 months, S/C 1.25±0.4 time, age of first estrus 2.7±0.6 years, age of first birth 3.7±0.5 years and postpartum estrus were 30–60 days. The result of research on the production of male buffalo body length was 205.3±1.7, and the body length of female buffalo was 127.2±4.3 cm, whereas the chest circumference of female was 205.3±1.7 cm and the chest circumference of the male was 189±2.8 cm. The estimated body weight of females and males were 516.7±7.7 kg and 445.2±11.9 kg. Based on the result of the research, the characteristics of swamp buffalo reproduction and production in Sragen Regency were classified as good.

This study aimed to determine the prevalence and factors that influence the incidence of retained placenta in dairy cows reared under an all-day cowshed housing system at KUD Tani Wilis, Sendang District, Tulungagung. This study used 216 dairy cows, that had already calved, that had been identified to have medical and reproductive records for data exploration. Data collected included the sex and weight of calf, single or twin calves, age of the dam, cowshed structure (floor, puddles on the floor, gutter, distance of cowshed to waste disposal, type of floor and roof, and sunlight exposure), feed of the dam (forage, concentrate, mineral supplements), frequency of retained placenta cases on calving intervals and days open of the dams. The prevalence of retained placenta was presented descriptively. Factors related to the retained placenta and its effect on calving interval and days open were analyzed by Chi-square test using Statistical Product and Service Solution (SPSS) software version 20 for Windows. The result showed that the prevalence rate of retained placenta was 19.91% of all dairy cow populations in the district. Furthermore, the sex of the calf, age of the dam, sunlight exposure, and the quantity of feed (forage and concentrate) were related to the retained placenta (p

This research aims to determine reproductive data on Sumatran elephants (Elephas maximus sumatranus) in the ETC and ERU of Way Kambas National Park, Indonesia during 1988-2021. Data recorded from the elephant population at both locations (ETC and ERU) includes the number, gender of elephants, elephant calves, ages and birth dates. Calving intervals and service periods were calculated from calving records of cows with a minimum parity of two. Data collection produced data on 47 elephant calves from 13 female elephants with at least twice the parity and 12 primiparous cows. Elephant reproductive records at ETC and ERU were: age (37.44 ± 9.03 vs. 29.75 ± 3.30 years), parity (2.78 ± 1.09 vs. 2.50 ± 0.58), and age at first birth (18, 11 ± 3.92 vs. 17.75 ± 0.50 years). While the calving interval was 1857.56 ± 870.81 vs. 1833.00 ± 305.18 days, and service period respectively 1229.44 ± 846.18 vs. 1210.50 ± 283.59 days, respectively. It can be concluded that the calving interval and service period for captive elephants at ETC and ERU were not much different and were within the normal range. Young cows showed better reproductive efficiency than older cows. Monitoring calves is very important. Further assistance is needed to improve elephant mobile veterinary services, increase diagnostic laboratory capacity, and educate camp managers, veterinary assistants, and mahouts about elephant diseases, their monitoring and treatment. In addition, the use of reproductive technology such as monitoring ovulation using ultrasound and carrying out artificial insemination was expected to increase reproductive efficiency. [ABSTRACT FROM AUTHOR]

Background: Breeding objectives are designed to achieve targeted dairy cow production goals, which can be affected by production type, farmer preferences, environmental factors and genetic factors individually or in combination. Breeding practices, such as both controlled and uncontrolled, and artificial insemination (AI) are the tools used to obtain the desired breeding objectives. The lower reproductive performance of indigenous dairy cows affects the total milk production and calf crops that are produced during their lifetime. Designing appropriate breeding objectives and breeding practices can improve the reproductive performance of dairy cows and their overall production performance. Materials and methods: The current study was conducted with the objective of evaluating the breeding, practices and performance of indigenous dairy cattle in the south western part of Ethiopia. The districts of Gesha and Chena were purposefully chosen. The study design for the 384 household surveys was a cross‐sectional survey with a simple random sample approach. Data analysis was carried out by MS‐Excel (2010) and the general linear model procedure of SAS of 2008. Results: The current study revealed that methods of breeding were predominantly natural‐controlled mating, followed by natural‐uncontrolled mating and AI in descending order. Breeding objectives were input function, output function, sociocultural and economic functions and assets and security functions in decreasing order of rank. Reproduction performance indexes of indigenous dairy cows age at first service (3.72 ± 0.05 years), age at first calving (AFC) (4.71 ± 0.07 years), calving interval (CI) (1.58 ± 0.03 years), days open (DO) (4.26 ± 0.11 months), services per conception in natural mating (1.4 ± 0.08) and AI (2.73 ± 0.14), age of bull at maturity (4.17 ± 0.74 years), interoestrus interval (23.18 ± 0.61 days), calves crop (7.53 ± 0.22) and the life span of indigenous dairy cow (11.94 ± 0.26 years) were significant (p < 0.01) between two districts, whereas the values of age of bull at maturity and number of services per conception in natural mating were significant (p < 0.05) between districts. Conclusions: Using AI and major reproduction performances, such as AFC, CI and DO of indigenous dairy cows in the study area, were very low. Therefore, concerned bodies should intervene to improve reproduction performance through the utilization of AI techniques, with the integration of forage development activities and improvements in livestock health care. [ABSTRACT FROM AUTHOR]

Household buffalo dairy farming is gaining popularity nowadays in Bangladesh because of the outstanding food value of buffalo milk as well as the lower production cost of buffalo compared to cattle. An initiative has recently been taken for the genetic improvement of indigenous dairy buffaloes. The present study was carried out to determine the influence of some environmental factors like age, parity, season of calving, calving interval, dry period on the lactation yield, and lactation curve of indigenous dairy buffaloes of Bangladesh. A total of 384 indigenous dairy buffaloes from the 3rd and 4th parity of seven herds under two different agroecological zones covering four seasons were selected and ear tagged for individual buffalo milk recording. A milk yield of 300 days (MY300d) was calculated following the International Committee for Animal Recording (ICAR) and the data were evaluated using the generalized linear model (GLM). In production traits, the mean of calculated lactation period (CLP), calculated lactation yield (CLY), and milk yield of 300 days (MY300d) of the overall population were 267.28 days, 749.36 kg, and 766.92 kg, respectively, whereas calving interval (CI) and dry period (DP) as reproductive traits were 453.06 days and 185.78 days, respectively. The season of calving, age of buffalo cows, population or herd, agroecological zone, calving interval, and dry period had significant effects on production traits (p < 0.05 to p < 0.001). The season of calving, level of milk production of 300 days, population, and agroecological zone significantly affected the reproduction traits (p < 0.01 to p < 0.001). Parity was found to be non-significant for both types of traits. The average peak yield of test day (TD) milk production was highest at TD4 (4.47 kg, 98th day of lactation). The average MY300d of milk production was the highest in the Lalpur buffalo population (1076.13 kg) and the lowest in the buffalo population of Bhola (592.44 kg). The correlations between milk production traits (CLP, CLY, and MY-300d) and reproduction traits (CI and DP) were highly significant (p < 0.01 to p < 0.001). Positive and high correlation was found within milk traits and reproduction traits, but correlation was negative between milk traits and reproduction traits. Therefore, these non-genetic factors should be considered in the future for any genetic improvement program for indigenous dairy buffaloes in Bangladesh.

This research aimed to identify the reproductive characteristics of Gayo buffaloes in the Mesidah Sub-district, Bener Meriah Regency. There were three locations of the current study namely Perumpaken Benjadi, Wer Tingkem, and Simpur, which were determined using the purposive sampling technique. A survey was used as the research method to obtain primary data and secondary data. Primary data were collected through direct interviews with buffalo livestock owners. They were asked a set of questions that had been prepared in a questionnaire. Secondary data were obtained from related agencies in Bener Meriah Regency. The number of respondents was 92 from four villages in the Mesidah Sub-district, Bener Meriah Regency. Breeders as respondents were selected using a purposive sampling method, with minimum requirements that they had raised two buffaloes that had given birth more than once and that the breeders had at least four years of farming experience. The research data were analyzed using descriptive statistic. The results showed that the Gayo buffaloes in the Mesidah Sub-district, Bener Meriah Regency, had reproductive characteristics that met the standards. This can be seen from the obtained data which were almost the same as the average age of the reproductive characteristics of buffaloes in Indonesia. Gayo buffaloes in the Mesidah Sub-district experienced the first estrus (puberty) at 33.83 months old, first mating at 34.61 months old, and first calving at 45.29 months. The average gestation period was 10.51 months, the calving interval was 15.5 months, and the average service period was 3.66 months, while maintenance management was carried out extensively. Based on the results, it can be concluded that the reproductive characteristics of Gayo buffaloes in the Mesidah Sub-district, Bener Meriah Regency, still meet the standards. The average reproductive characteristics of Gayo buffaloes are generally the same as the average characteristics of other buffaloes in Indonesia.

This study aimed to determine the reproductive performance of female buffalo in Boyolali Regency, Central Java, Indonesia. The sampling method used was the purposive sampling method. The number of respondents was 30 buffalo farmers with a total sample were 100 female buffalo. Collecting data using interview, observation, and literature study methods and analyzing descriptively. The data that has been obtained is then calculated into percentages, averages, and standard deviations, then analyzed descriptively. Buffalo farmers are rice farmers who are still productive with a dominant age of less than 65 years. The main feed given was rice straw, and 64% of buffalo received additional field grass when grazing. The farming experience of farmers was quite long, which is more than 15 years, and was classified as a small-scale farm with the number of buffalo less than 5 heads. The management system used by buffalo farmers is mostly (90%) semi-intensive. The values of gestation length, postpartum estrus, and postpartum estrus were 308.0±7.4 days, 102.2±6.2 days, and 406.8±8.9 days, respectively. The age of first calving for buffalo in the study in Boyolali Regency was 3.60 ± 0.3 years. This study concluded that the reproductive performance of buffaloes in smallholder farms in Boyolali Regency, Central Java Province was in good condition

This study aimed to determine the prevalence and factors that influence the incidence of retained placenta in dairy cows reared under an all-day cowshed housing system at KUD Tani Wilis, Sendang District, Tulungagung. This study used 216 dairy cows, that had already calved, that had been identified to have medical and reproductive records for data exploration. Data collected included the sex and weight of calf, single or twin calves, age of the dam, cowshed structure (floor, puddles on the floor, gutter, distance of cowshed to waste disposal, type of floor and roof, and sunlight exposure), feed of the dam (forage, concentrate, mineral supplements), frequency of retained placenta cases on calving intervals and days open of the dams. The prevalence of retained placenta was presented descriptively. Factors related to the retained placenta and its effect on calving interval and days open were analyzed by Chi-square test using Statistical Product and Service Solution (SPSS) software version 20 for Windows. The result showed that the prevalence rate of retained placenta was 19.91% of all dairy cow populations in the district. Furthermore, the sex of the calf, age of the dam, sunlight exposure, and the quantity of feed (forage and concentrate) were related to the retained placenta (p <0.05). In addition, retained placenta increased along with extending of days open and calving interval. It could be concluded that the factors that influenced the prevalence of retained placenta were the sex of the calf, the age of the cow, the feed and concentrate, and the cowshed that is not facing the sun. [ABSTRACT FROM AUTHOR]

Context: Cow survival is an important trait for dairy farm profitability and animal welfare, yet it is difficult to improve because of its complexity arising, in part, from varied reasons for culling and delay in getting actual culling data, which leads to low accuracy and instability of genetic predictions. Aims: To explore the benefits of partitioning the cow survival trait into 'early survival' (survival coded as a binary trait from the first to the second lactation) and 'late survival' (survival from the second to later lactations) on genetic predictions in addition to predictors of culling decisions. Methods: The raw phenotypic survival records for 1 619 542 Holstein and 331 996 Jersey cows were used in our study. All cows within each herd were allocated to either a reference or validation set. The accuracy and stability of genetic predictions were compared across lactations in the validation set. Further, we estimated the phenotypic and genetic correlation between overall, early or late cow survival and production, type, workability, and fertility traits using bivariate sire models. Key results: The heritability of overall survival in Jerseys (0.069 ± 0.003) was higher than in Holsteins (0.044 ± 0.001). The heritability of early survival was higher than that of late survival in Holstein (0.039 ± 0.002 vs 0.036 ± 0.001) and Jersey (0.080 ± 0.006 vs 0.053 ± 0.003). The genetic correlation between early and late survival was high in both breeds (0.770 ± 0.017 in Holstein and 0.772 ± 0.028 in Jersey). Adding survival information up to the sixth lactation had a large effect on genetic predictions of overall and late survival, whereas the predictions of early survival remained the same across lactations. Milk and protein yields, somatic cell score, fertility and temperament were highly correlated with early survival in Holstein and Jersey. However, the genetic correlations between production, type or workability traits and late survival were generally weaker than those and early survival. Conclusions: Early and late survival should be considered as different traits in genetic evaluations, because they are associated with different culling decisions. Implications: Partitioning cow survival into early and late survival and analysing them as two correlated traits could improve the accuracy and the stability of estimated breeding values compared with analysing overall survival as a single trait. Survival in dairy cows is an important welfare and economic trait that is affected by many factors. The reasons for culling a cow from the first to the second lactation are often different from the ones influencing survival of cows in later lactations. To incorporate this possible difference for genetic evaluations, we explored the benefits of partitioning the cow survival trait into 'early survival' and 'late survival'. This could improve the accuracy and the stability of genetic predictions. [ABSTRACT FROM AUTHOR]

The economic benefit of dairy cattle breeding units is a function of milk production volume, reproductive efficiency and herd health that various environmental and physiological factors such as nutrition, parity and offspring sex can play a role in the incidence of these traits. the main aim of this study was to investigate the effect of calf sex on production, reproductive and udder health traits in Isfahan Holstein cows. The data included 37,038 Holstein cows from the first to fifth lactation period from 13 industrial herds during the years 2005 to 2017. To investigate the effect of calf sex on the production and health traits, the mixed linear model procedure and on the reproduction traits, GLIMMIX procedure of SAS9.4 software were used. The results showed that cows with female calf had higher 305-days of milk (90.7 kg) in compared to cows with male calf (P<0.01). For percentage of 305-d fat and protein and the number of days from calving to first service, the effect of calf sex different was low but significant (P<0.05). However, no significant difference was observed between male and female calves for other traits. According to the results, it seems necessary to consider the effect of calf sex in the genetic evaluation of Isfahan Holstein cows and also cost-benefit analysis of the use of sexed semen in herds. [ABSTRACT FROM AUTHOR]

This research aims to determine reproductive data on Sumatran elephants (Elephas maximus sumatranus) in the ETC and ERU of Way Kambas National Park, Indonesia during 1988-2021. Data recorded from the elephant population at both locations (ETC and ERU) includes the number, gender of elephants, elephant calves, ages and birth dates. Calving intervals and service periods were calculated from calving records of cows with a minimum parity of two. Data collection produced data on 47 elephant calves from 13 female elephants with at least twice the parity and 12 primiparous cows. Elephant reproductive records at ETC and ERU were: age (37.44 ± 9.03 vs. 29.75 ± 3.30 years), parity (2.78 ± 1.09 vs. 2.50 ± 0.58), and age at first birth (18, 11 ± 3.92 vs. 17.75 ± 0.50 years). While the calving interval was 1857.56 ± 870.81 vs. 1833.00 ± 305.18 days, and service period respectively 1229.44 ± 846.18 vs. 1210.50 ± 283.59 days, respectively. It can be concluded that the calving interval and service period for captive elephants at ETC and ERU were not much different and were within the normal range. Young cows showed better reproductive efficiency than older cows. Monitoring calves is very important. Further assistance is needed to improve elephant mobile veterinary services, increase diagnostic laboratory capacity, and educate camp managers, veterinary assistants, and mahouts about elephant diseases, their monitoring and treatment. In addition, the use of reproductive technology such as monitoring ovulation using ultrasound and carrying out artificial insemination was expected to increase reproductive efficiency.

The purpose of the research was to study the main indicators of the reproductive ability of Black-and-White cows, depending on the proportion of Holstein genes. As the material for the research there were taken the data of breeding and zootechnical records of cows of Black-and-White breed of CJSC Semenovsky Breeding Plant of the Mari El Republic. The results of the research showed that with an increase in the proportion of thorough-bredness on the Holstein breed the reproductive ability of cows improved. Thus, the first-calf heifers with a low proportion of Holstein genes (up to 12.5 %) had the latest age of the first fruitful insemination and the first calving (21.9 months and 32.3 months). With an increase in thorough-bredness up to 87.6 % and more, the age for the first insemination decreased by 7.7 months (31.8 %), the age of the first calving - by 7.4 month (21.8 %), fertility index increased by 5.8 (14.6 %). At the same time, the duration of the service period in high-blooded animals increased by 18.8-26.4 days (15.8-23.8 %). The duration of the calving interval in all genetic groups exceeded the optimal time and changed in accordance with the change in the service period. The longest calving interval was in cows with the thorough-bredness degree of 87.6 % (13.8 months), which was 0.1-0.7 months longer than in animals of other genetic groups. There was a low coefficient of reproductive ability of the studied animals of all genetic groups ‒ 0.91-0.93. The significant influence of Holstein genes on the age for the first fruitful insemination (ɳ2 = 9.57 %), the first calving (ɳ2 = 8.80 %) and the fertility of cows (ɳ2 = 1.98 %) (P≤0.05) was established. The effect of the genotype on the duration of the service period and calving interval was weak (ɳ2 = 0.09 % and ɳ2 = 0.26 %) and unreliable.

Copyright of Kocatepe Veterinary Journal / Kocatepe Veteriner Dergisi is the property of Afyon Kocatepe University, Faculty of Veterinary Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a herd of Japanese Black (JB) breeding cattle with sporadic reproductive disorders was continuously monitored for an additional year to assess the effects of the urinary zearalenone (ZEN) concentration and changes in parameters (AMH and SAA) with time-lag variables and herd fertility (reproductive performance). This herd had high (exceeded the Japanese dietary feed regulations) urinary ZEN and rice straw ZEN concentrations (1.34 mg/kg). Long-term data of the herd with positive ZEN exposure revealed a decreasing ZEN concentration in urine and a gradual decrease in the AMH level with age. The AMH level was significantly affected by the ZEN value 2 months earlier and the AMH level in the previous month. The changes in ZEN and SAA values were significantly affected by the ZEN and SAA values in the previous month. Additionally, calving interval data between pre-monitoring and post-monitoring showed a significantly different pattern. Furthermore, the calving interval became significantly shorter between the time of contamination (2019) and the end of the monitoring period (2022). In conclusion, the urinary ZEN monitoring system may be a valuable practical tool for screening and detecting herd contamination in the field, and acute and/or chronic ZEN contamination in dietary feeds may affect herd productivity and the fertility of breeding cows. [ABSTRACT FROM AUTHOR]

Photo-identification data for southern right whale cow–calf pairs on the South African calving grounds provide one of the longest abundance time-series for any whale population worldwide. Following a very steady increase from a heavily depleted state, surveys since 2015 reflect many notably low counts. These data are analysed to investigate whether these low counts can be explained by changes in reproduction-related parameters. This necessitates a modification to an earlier reproduction model for these whales, fit to photo-identification data to allow for early abortions; hence, a whale pregnant one year can again be pregnant the next. This can account for an increase in calving intervals in a way that differs from a whale resting for another year or an increase in late-abortion probability. This modification was able to account for the low number of sightings of cow–calf pairs over the 2015 to 2020 period (excepting for 2018), though the estimated probability of sighting a cow–calf pair in 2018 is somewhat low given a nearly unchanged annual survey effort. Hence, low numbers of sightings of females with calves for five of the years from 2015 to 2020 can be explained by changes in reproduction-related parameters rather than an increased natural mortality which is inconsistent with the photo-identification data. Changing environmental (particularly feeding) conditions seems to be the likely cause, possibly associated with a changed distribution of these whales. The estimated number of all whales in the population in 2020 is 6 470 (SE 285), with the number of parous females estimated to have increased 15-fold over the last four decades. [ABSTRACT FROM AUTHOR]

Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales (Balaena mysticetus) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ15N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8–5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation.

The specialized herds of the high tropics of Nariño are characterized by semi-intensive breeding models, that is, feeding based on grazing and supplementation. The objective was to analyze the milk production of grazing Holstein cows under conditions of the high tropics, taking into account the energetic and protein metabolites, and their relationship with the dry matter intake (CMS/Kg/d), the body condition (BC), and the reproductive variables. Three periods of lactation were evaluated, thus, between 4-10 days (P1), 45-55 days (P2), and between 185-200 days (P3). The investigation was carried out in four dairy production farms. The forage supply consisted of a mixture of Lolium hybridum, Cenchrus clandestinus Hoschst ex Chiov, Holcus lanatus and Trifolium repens, plus commercial concentrate. A total of 24 Holstein animals (six per productive system) from three births onwards were used, from which blood samples were obtained to determine: non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), triglycerides, cholesterol, glucose, total protein (PT), and blood urea nitrogen (BUN). The results showed that milk production during P1 is influenced by CC and body weight (Kg) by +0.04 liters of milk per unit of change in this variable. In P2, the positive incidence variables were PT, BUN, glucose, NEFA, BHB, triglycerides, and cholesterol, and in P3, the increase in CMS made it possible to show that as lactation progresses in more than 180 days, the animals substantially improve their body condition; likewise the NEFA and BHB indicators are related to a better reproductive response.

Simple Summary: Fertility is one of the most important traits for productivity in extensive beef production systems, since it has a major effect on the number of calves born and, as a result, the quantity of weaned calves produced per year. However, it is difficult to improve this trait under extensive conditions, mainly due to the lack of reliable and easy-to-obtain selection criteria. In this study, fertility was analyzed using reproductive efficiency, which was calculated as the deviation between the optimal and real parity number of females at each age. We demonstrated a high h2 value (0.30) using a classic repeatability model and a random regression model (ranging from 0.24 to 0.51), which suggests that the latter model can be recommended to improve fertility in beef breeds raised under extensive environmental conditions such as the Retinta. In addition, we performed the first GWAS analysis looking for SNP genetic markers associated with this character in cattle, which showed five markers significantly associated with the trait located on BTA4 and BTA28. Finally, the functional analysis revealed the presence of five candidate genes located within these regions, which were previously shown to be related to fertility in cattle and mice models. In this study, we analyzed the variation of reproductive efficiency, estimated as the deviation between the optimal and real parity number of females at each stage of the cow's life, in 12,554 cows belonging to the Retinta Spanish cattle breed, using classical repeatability and random regression models. The results of the analyses using repeatability model and the random regression model suggest that reproductive efficiency is not homogeneous throughout the cow's life. The h2 estimate for this model was 0.30, while for the random regression model it increased across the parities, from 0.24 at the first calving to 0.51 at calving number 9. Additionally, we performed a preliminary genome-wide association study for this trait in a population of 252 Retinta cows genotyped using the Axiom Bovine Genotyping v3 Array. The results showed 5 SNPs significantly associated with reproductive efficiency, located in two genomic regions (BTA4 and BTA28). The functional analysis revealed the presence of 5 candidate genes located within these regions, which were previously involved in different aspects related to fertility in cattle and mice models. This new information could give us a better understanding of the genetic architecture of reproductive traits in this species, as well as allow us to accurately select more fertile cows. [ABSTRACT FROM AUTHOR]

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Background: No dairy breed or crossbreed has superior overall performance in all environments; therefore, it is necessary to determine which crossbreed is the most suitable for the Mexican tropic and what proportion of European breed is optimum for reproduction. Objective: To assess the effect of the proportion of Bos taurus (Bt) genes on reproductive performance of Holstein×Zebu (HZ) and Brown Swiss×Zebu (BZ) cows, and compare reproductive performance of these genotypes in a dual-purpose production system. Methods: Cows were maintained in a rotational grazing system on African star grass (Cynodon plectostachyus) in Veracruz, Mexico. Cows were milked twice daily. Calves were kept tied to the side of their dams while the cows were milked. Results: The percentage of Bt genes did not affect (p>0.05) fertility traits (age at first calving, days to first service after calving, services per conception, conception rate at first service, days open until conception, gestation length, and calving interval) of BZ cows. In contrast, HZ cows with less than 75% Holstein (H) genes were 0.3 years younger (p

Is generally known there is antagonistic relationship between production and reproduction traits. We observed this relationship in dataset of 1 197 478 daily milk records of Holstein cows on the first lactation only, first time calved during years 2003-2009. We found increased milk production and prolonged calving interval during this period. We observed highest milk production (7604 kg) on standardized 1st lactation for cows with longest calving interval in compare to cows with shortest calving interval (7079 kg). Positive significant correlation (0.56775, P

The aim of this paper was to study the influence of calving interval on the number of somatic cells from milk in Romanian Black and White cows. The study was conducted on a total of 125 lactations from 92 cows. Data were recorded and statistically analyzed by ANOVA/MANOVA method determining the means and dispersion indices. The results indicated that calving interval influenced significantly (p < 0.05) changes in the somatic index between calving interval below 350 days and calving interval between 351 and 450 days (0.33). Milk produced from cows with calving interval below 350 days had the smallest somatic index (5,33) which corresponds to a number of somatic cells around 214000 cells/ml. Cows with calving interval between 351 and 450 days had the highest value of the somatic index 5.67, which corresponds to a concentration of 468000 somatic cells/ml.

Context: Dairy farming in Brazil is characterised by heterogeneity in production techniques, herds and kinds of producers; nonetheless, it has expanded in recent years. The data available in the scientific literature regarding breeds used in the system are inconsistent and may not represent the current genetic, productive and reproductive profile of Brazilian herds. Aim: This study was developed to understand differences between animals used in experiments and those in breed control assessments. We aimed to evaluate data of Holstein, Gyr, Guzerat, Jersey, Sindhi, Brown Swiss, Holstein × Gyr and Holstein × Guzerat cattle on the traits 305-day milk yield, fat and protein contents, lactation length, age at first calving, and calving interval by comparing research literature and national official control records. Methods: National breeders' associations (NBAs) for each breed or cross were asked to send their official control from 2019 for comparison with 15 years of published data that we retrieved from the literature. Key results: Holsteins showed the closest mean for milk yield between literature and NBA data. In Holstein × Gyr crosses, increasing the proportion of Gyr genes decreased milk yield. Jersey data showed the greatest variance between the literature and NBA. For Brown Swiss milk fat, literature values were 12.7% above NBA values. Holsteins had the longest lactation (305 days), and 5/8 Holstein × Gyr the shortest (262 days). For age at first calving, Jerseys were the youngest (26.3 months) and Guzerats the oldest (45.7 months). Jersey cows showed the shortest (best) mean calving interval (12 months), and Sindhi the longest (17 months). NBA data were not available for comparison for some traits in some breeds/crosses. Conclusions: Holstein was the most productive breed. Holstein × Gyr crosses, because of adaptation and management, were able to express their productive and reproductive potentials. There was variance between literature and NBA data. Implications: We expected that the literature data would somewhat represent the NBA data; however, for most traits, NBA data do not coincide (or do not exist). Literature data need to be collected to represent more closely what is happening at the field level in the national dairy industry. This study is a systematic analysis of the Brazilian dairy industry comparing data from scientific literature and breeders' association official controls, in order to understand differences between animals used in experiments and those in breed control assessments. There was a considerable lack of official data for most traits, and a large difference between official data and the literature. Literature data need to be collected that better represent what is happening at the field level in the national dairy industry. [ABSTRACT FROM AUTHOR]

Copyright of Indonesian Journal of Veterinary Science / Jurnal Kedokteran Hewan is the property of Universitas Syiah Kuala, Faculty of Veterinary Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to assess the reproduction parameters of modern dairy cattle in the west of Algeria. Our experimentation included 2270 dairy cows selected from three different farms; two of them situated in the Sidi Bel Abbes region (Taleb and Sidi Lahcen) and the third farm situated in the region of Temouchent (Oued Sebbah). These cows were followed from January 2017 to December 2018 to determine their reproduction performance. Our results recorded that the mean cows' age during the first calving was 30± 2.2 months with an extreme of 22 to 43 months. The interval registered between the first calving and mating was 85.0 ± 6.3 days with extremes of 40 to 110 days. In our results, an average of 94.6 ± 7.5 days with extremes of 38 to 152 days was recorded between calving and the fertilizing protrusion. The cow's interval between calving was 423 ± 63.2 days with extremes of 301 to 601 days. Modern infrastructure, food in terms of quality and quantity as well as employing a qualified workforce in farms can significantly improve the performance of our animals. [ABSTRACT FROM AUTHOR]

Dairy production relies predominantly on a few, selectively bred, high-yielding dairy breeds, resulting in a surplus of low-value male offspring. This situation leads to a conflict between a growing demand for milk and low appreciation for dairy calves. Extending lactation could reduce the number of calves born. This study aimed to assess the current use of extended lactation in dairy production in Southern Germany, identify the perceived potential, and determine the biological potential extended lactation has to reduce calf numbers. A survey from 2020 with 310 farmers was analysed. A total of 145 (46.8%) farmers used extended lactation. The use of extended lactation on farms correlated significantly with breed, milk yield, interest in continuing or implementing the use of extended lactation, and the indicated feasibility of extended lactation. The perceived potential was assessed by 39.8% of farmers as "high" to "very high". A total of 17 (12.8%) farmers currently not using extended lactation were identified as potential adopters. Together with existing adopters, this could result in 52.3% of farms using extended lactation, which could biologically reduce calf numbers by 7.3% or 14.1% p.a., when extended by three or six months, respectively. This adoption potential shows that extended lactation can reduce calf numbers considerably, addressing both ethical and economic concerns in dairy farming and benefiting farmers as well as society.

This study was conducted to find out how much losses the breeders get when their cattle experience a decline in day open (DO), service per conception (S/C), and calving interval (CI).There were 108 lactating dairy cows from the dairy farm, Wagir District, Malang Regency.The data that has been taken is then processed by analysis using linear regression method.The results of the analysis prove that reproductive management has an effect of 82% on farmer expenditure.For each setback DO per day, the farmer pays Rp. 609,05.Meanwhile, for each additional S/C the farmer pays Rp. 99,921.7.For each setback the farmer CI will incur a fee of IDR 228,54 / day.So that the equation found is expendses = 609,05 (DO) + 99,921.7 (s / c) +228,54 (CI).

Large calving intervals in water buffalo cows is attributed to the existence of periods of the year when sexual activity is absent. It is considered that if fertilization did not occur before the buffalo cows entered in the winter season, when kept indoors, then it will take a significant longer time until they enter again in heat and the calving interval will be negatively influenced. The work was conducted over 4 years and consisted of the evaluation of ovarian response following administration of a prostaglandin hormone (PGF2α) during the winter period for a number of 61 buffalo cows, between 5 and 14 years of age. In 22 buffalo cows that showed oestrus within 5 days of PGF2α administration, two artificial inseminations were performed at 12 hours intervals. In 39 buffalo cows that did not show any signs of oestrus, a second dose of PGF2α was administrated 11 days after the first administration, after which they were artificially inseminated at 48 and 78 hours, respectively. Of the 22 buffalo cows that showed oestrus, 19 cows became pregnant, and out of the 39 buffalo cows with prolonged treatment, only 20 heads remained pregnant. The treatment of sexual inactivity in water buffalo cows during indoor hosing by hormonal methods with PGF2α leads to the shortening of the calving interval, the cost of hormonal treatments being balanced by the increase in the number of calves obtained and the milk production.

The aim of the current research was to determine the influence of calving year and season on calving interval (CI) in Romanian Brown breed. A total of 250 data recorded from 150 lactations of 50 Romanian Brown cows raised between 2018 and 2020 were included in the current study. The year proved to exert a significant effect (p≤0.01) on calving interval, this parameter recording an increased tendency. Comparable values were recorded according to season of calving (p>0.05). Concluding, year of calving was the main influential factors for this particularly reproductive trait. In this respect, additional studies should be performed in order to include other factors, validate their influence and properly manage of its.

Objective The objective of this study was to define a new composite trait for Holstein dairy cows and evaluate the possibility of joint improvement in milk and fertility traits. Methods A data set consisting 35,882 fertility related records (days open [DO], calving interval [CI], and number of services per conception [NSC], and total milk yield in each lactation [TMY]) was collected from 1998 to 2016 in Polish Holstein-Friesian breed herds. In this study TMY, DO, CI, and lactation length of each cow was used to obtain composite milk and fertility traits (CMF). Results Moderate heritability (0.15) was estimated for composite trait that was higher than heritability of female fertility related traits: DO 0.047, CI 0.042, and NSC 0.014, and slightly lower than heritability of TMY 0.19. Favourable genetic correlations (−0.87) were estimated between CMF with TMY. Spearman rank correlation coefficients between breeding value of CMF with DO, CI, and TMY were high (>0.94) but with NSC were moderate (0.64). Selection on CMF caused favourable correlated genetic gains for DO, CI, and TMY. Different selection indices with different emphasis on fertility and milk production were constructed. The amount of correlated genetic gains obtained for DO and total milk production according to selection in CMF were higher than of genetic gains obtained for DO and TMY in selection indices with different emphasis on milk and fertility. Conclusion The animal selection only based on a composite trait - CMF proposed in current study would simultaneously lead to favourable genetic gains for both milk and fertility related traits. In this situation CMF introduced in current study can be used to overcome to limitations of selection index and CMF could be useful for countries that have problems in recording traits, especially functional traits.