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Qianhua Mutton Merino is a dual-purpose (meat and wool) breed of sheep that has been newly developed in China. In this study, we assessed the growth and development of the Qianhua Mutton Merino sheep breed under house feeding conditions by measuring the body weight and chest circumference of 2300 rams and ewes of this breed aged 0–24 months. Based on the fitting results of three nonlinear growth models, namely Logistic, Gompertz, and von Bertalanffy, in Qianhua Mutton Merino, we selected the von Bertalanffy model because of its highest fitting degree among all models (R2 > 0.977). The significant analysis of the combined fixation of each sheep body's weight and bust took place (A: mature body weight, B: adjustment parameter, K: instant relative growth rate). The results revealed that parameters A, B, and K of body weight and chest circumference have high heritability and thus could be used as target traits for genetic improvement. Moreover, the correlation strength among A, B, and K suggested that these parameters can be used as a reference to adjust the genetic parameters in the growth model to genetically improve the body size of Qianhua Mutton Merino during breeding. [ABSTRACT FROM AUTHOR]

Introduction: Chinese Holstein in South China suffer heat stress for a long period, which leads to evolutionary differences from Chinese Holstein in North China. The aim of this study was to estimate the genetic parameters of fertility traits for Chinese Holstein in South China. Methods: A total of 167,840 Chinese Holstein heifers and cows from Guangming Animal Husbandry Co., LTD farms were used in this study. The fertility traits analyzed were calving interval (CI), days open (DO), age of first service (AFS), age of first calving (AFC), calving to first insemination (CTFS), first insemination to conception (FSTC), gestation length (GL), non-return rate to 56 days (NRR), and number of services (NS). Results: The descriptive statistics revealed that the same trait in heifers performed better than in cows, which was consistent with the other studies. The heritabilities of fertility traits in this study ranged from close to 0 (for NS of cows) to 0.2474 (for AFC of heifers). The genetic correlation of NRR between heifers and cows was 0.9993, which indicates that the NRR for heifers and cows could be treated as one trait in this population. Conclusion: The heritabilities of fertility traits in Chinese Holstein in south China were quite different from the heritabilities of fertility traits in North China. NRR56, NS, AFC, and CI were suggested to be included into the selection index to improve fertility performance of Chinsese Holstein of south China. The results of this study could provide genetic parameters for the animal breeding program of Chinese Holstein in the south of China. [ABSTRACT FROM AUTHOR]

Simple Summary: Ovum pick up and in vitro embryo production (OPU-IVEP) is a critical technique in the dairy industry that is attracting a lot of attention, especially in China's dairy industry. The aim of the technique is to produce as many embryos with excellent genetic material as possible. However, there is a large variation in the ability of donor cows to produce embryos, and this ability is heritable. In this case, genetic selection and animal breeding will be beneficial to improving efficiency. Considering the large differences among different populations, the genetic parameters regarding the Chinese population are currently essential for genetic selection in the future. In this study, we analyzed the phenotypic and genetic characteristics of in vitro embryo production traits in Chinese Holstein cattle. The results of this study may help to understand the breeding potential of in vitro embryo production traits. Ovum pick up and in vitro embryo production (OPU-IVEP) is an essential technique in the dairy industry. The production efficiency of OPU-IVEP is significantly influenced by various factors, and phenotypic and genetic characteristics are highly variable in different populations. The objectives of this study were (1) to reveal the phenotypic characteristics, including population distribution, and impacts of donor age and month on in vitro embryo production and (2) to estimate genetic parameters for five in vitro embryo production traits in Chinese Holstein cattle. A total of 7311 OPU-IVEP records of 867 Holstein heifers from August 2021 to March 2023 were collected in this study. Five in vitro embryo production traits were defined, including the number of cumulus–oocyte complexes (NCOC), the number of cleaved embryos (NCLV), the number of grade I embryos (NGE), and the proportion of NCLV to NCOC (PCLV) and NGE to NCOC (PGE). A univariate repeatability animal model was employed to estimate heritability and repeatability, and a bivariate repeatability animal model was employed to estimate the genetic correlations among five in vitro embryo production traits. It was found that the in vitro embryo production traits were significantly influenced by season, as the NGE and PGE were significantly decreased from June to August. In addition, the production efficiency of OPU-IVEP was also influenced by donor age. On the observed scale, the estimates of heritability were 0.33 for NCOC, 0.24 for NCLV, 0.16 for NGE, 0.06 for PCLV, and 0.10 for PGE, respectively. On the log-transformed scale, the estimates of heritability of NCOC, NCLV, and NGE were 0.34, 0.18, and 0.13. The genetic correlations among NCOC, NCLV, and NGE ranged from 0.61 (NCLV and NGE) to 0.95 (NCOC and NCLV), considering both scales. However, there were low genetic correlations between NCOC and proportion traits (PCLV and PGE) on both the observed scale and the log-transformed scale. In the end, the variation in Chinese Holstein cattle was found to be considerable. The EBV value and average NCOC, NGE, and PGE for the top 10% donors presented extreme differences to those for the bottom 10% donors for NCOC (24.02 versus 2.60), NGE (3.42 versus 0.36), and PGE (30.54% versus 3.46%). Overall, the results of this study reveal that in vitro embryo production traits are heritable with low to high heritability, and the count traits (NCOC, NCLV, and NGE) and proportion traits (PCLV and PGE) reflect different aspects of in vitro embryo production and should be incorporated into genetic selection for improving the embryo production efficiency of dairy cattle. [ABSTRACT FROM AUTHOR]

Qingyuan partridge chicken is one of the most well‐known Chinese indigenous yellow broilers. In breeding programmes, five traits are usually selected when the chickens are 105 days old, namely body weight (BW), comb height (CH), shank length (SL), shank girth (SG) and feather maturity (FM). The objective of this study was to estimate the genetic parameters of these five traits, especially direct additive genetic correlations, to lay the foundation for balanced selection of Qingyuan partridge chickens. Approximately 9600 records were used for estimation. Variance components for these five traits were estimated using three multi‐trait models incorporating different effects via Gibbs sampling. Based on model 1 in which the random effects included direct additive genetic effects and residuals, the estimated direct heritabilities for BW, CH, SL, SG and FM were 0.29 ± 0.04, 0.53 ± 0.04, 0.47 ± 0.04, 0.43 ± 0.05 and 0.18 ± 0.03, respectively. The direct genetic correlations ranged from −0.08 to 0.46. When additionally considering maternal additive genetic effects (model 2), the estimates of direct heritabilities and absolute values of direct additive genetic correlations were smaller. The heritabilities were 0.14 ± 0.04, 0.40 ± 0.02, 0.34 ± 0.05, 0.27 ± 0.05 and 0.12 ± 0.03 for BW, CH, SL, SG and FM, respectively. The direct additive genetic correlations ranged from −0.33 to 0.36. More specifically, the direct additive genetic correlations between BW and CH, SL, SG and FM were 0.19 ± 0.13, 0.15 ± 0.15, 0.36 ± 0.15 and − 0.33 ± 0.21, respectively. The genetic correlations of FM with SL, SG and CH were − 0.15 ± 0.15, −0.08 ± 0.17 and 0.18 ± 0.15, respectively. The direct genetic correlations between CH and SG and SL were − 0.02 ± 0.11 and − 0.20 ± 0.11, respectively, and that between SL and SG was 0.19 ± 0.11. The total heritabilities and maternal additive genetic correlations ranged from 0.16 to 0.44 and from −0.13 to 0.61, respectively. The third model also included the maternal permanent environmental effect for BW. The estimates of direct heritability, direct additive genetic correlation, total heritability and maternal additive genetic correlation were only slightly different from those based on the second model. Therefore, the maternal additive genetic effect has a large effect on the estimation of genetic parameters, and it is better to consider this effect in the genetic evaluation of these five traits. Relatively high direct and maternal additive genetic correlations for most trait pairs suggested that it is better to jointly evaluate these five traits in breeding programmes. [ABSTRACT FROM AUTHOR]

Increasing soybean yield is essential for China. In order to secure the desire soybean yield gains, it is important to understand how changes in climate and technology impact soybean yield. First, we used historical climate and specific technology data assessed the impact of historical climate and technology on soybean yield in China. Second, combined with the historical yield linear trends, we projected future soybean yield under climate change and technology improvement. We collected the historical climate data (daily maximum and minimum temperatures, precipitation, and solar radiation) and actual crop data (soybean yield and agricultural management practices: sowing date, total agricultural machinery, effective irrigation area, pesticide application amount, and rural labor force) of 1312 soybean-growing counties in China from 1990 to 2017. Besides, we calibrated and validated the vegetative and reproductive stages, and the yield formation process genetic parameters of soybean of different maturity groups in DSSAT-CROPGRO-Soybean model by a five-year cycle based on soybean field experiment data. We defined agricultural management practices and genetic parameters as technology, and used Bayesian methods to conduct an impact assessment of historical climate and technology changes on soybean yield. We also projected soybean yield from 2021 to 2100 under climate change and different cases of technology improvement. From 1990 to 2017, more than 90% of the study counties showed an increase in soybean yield, although the yield increase slowed down after 2010. Agricultural management practices and genetic parameters changes increased soybean yield by 16% (−24 to 50%) and 6% (−14 to 24%), respectively, while climate change decreased soybean yield by 1% (−14 to 18%). The positive impacts of agricultural management practices were mainly attributed to pesticide application amount and total agricultural machinery. With changes in agricultural management practices alone, soybean yield showed a plateau or even a decrease after 2010. If the technology remains at the level it was in 2010s, soybean yield would decrease in the future in 49% of the counties. Based on climate, soybean yield, specific agricultural management practices and genetic parameters data, we quantified the impacts of historical climate and technology on soybean yield in China. Besides, we projected future soybean yield under climate change and different cases of technology improvement, and discussed possible solutions for future increasing soybean yield. This work has practical significance for understanding climate and technology impacts on soybean yield, and implementing countermeasures to address future climate change and increase yield. [Display omitted] • Understanding how changes in climate and technology impact soybean yield is essential for China. • The study aimed to assess the impact of climate and technology on soybean yield, and project future soybean yield. • Bayesian methods, and climate, soybean yield, agricultural management practices and genetic parameters data were used. • Historical technology increased soybean yield, however, yield in 49% counties would decrease in future if technology level remains as 2010s. • This work has practical significance for implementing countermeasures to address future climate change and increase yield. [ABSTRACT FROM AUTHOR]

Abstract: Genetic parameters and selection responses were obtained for fillet weight and fillet yield of Progift Nile tilapia (Oreochromis niloticus) in China after six generations of multi-trait selection for growth and fillet yield. A total of 9619 test fish representing 687 full-sib families in six generations (G1–G6) of Nile tilapia originating from the GIFT breed were sacrificed to record skin-on fillet weights. Some of these skin-on fillets were further processed by skinning (5971 test fish) and trimming (4633 test fish) to allow calculations of three estimates of fillet yield (based on skin-on, skinned and trimmed fillets). Recorded fillet weights were positively influenced by body weight and negatively influenced by age at recording. The heritability (h2) of skin-on fillet weight showed large variation in magnitude between generations (range of 0.00–0.45), but was of medium magnitude (0.30) when analyzing all data combined. The h2 of fillet yield, which varied between 0.08 and 0.30 in different generations, was relatively stable (0.17–0.23) for different estimates of fillet yield when analyzing across all generations. Including all data, the effects common to full-sibs (c2) accounted for 8% and 1–2% of the total phenotypic variance, respectively, for skin-on fillet weight and different estimates of fillet yield. The genetic correlations between different estimates of fillet yield were all very high (0.95–0.97 when analyzing all data) showing that it is sufficient to select based on skin-on fillet yield. The genetic correlation between skin-on fillet weight and body weight at harvest was also very high (0.97), while that between fillet yield and fillet weight was of moderate magnitude (0.33). The genetic correlation between fillet yield and body weight at harvest was not significantly different from zero. Genetic trend analysis based on all data predicted accumulated selection responses of 121g (1.87 phenotypic standard deviation units) larger skin-on fillet weight and 1.2%-units higher skin-on fillet yield after six generations of multi-trait selection. It is concluded that the ongoing program in China has resulted in considerable genetic improvement of fillet weight, and that genetic changes of fillet yield is a much slower process (0.2%-units per generation). Implications for commercial selective breeding programs are discussed. [Copyright &y& Elsevier]

Abstract: Genetic parameters and selection responses were obtained for growth of Progift Nile tilapia (Oreochromis niloticus) in China after six generations of multi-trait selection. About 64,000 tagged fingerlings representing 787 full-sib families in seven generations of Nile tilapia originating from the GIFT breed were tested in freshwater earthen ponds, floating cages in reservoirs and a brackish water earthen pond in Guangdong and Hainan Provinces of China. Individual body weight was recorded on 25,000 of these at the expected time of sexual maturation and 50,000 at harvest to estimate genetic parameters for growth rate. Heritability (h2) estimates for body weight showed large variation in magnitude (0.00–0.52) when analyzing data from each test environment and generation separately. Estimates obtained in floating cages and a brackish water pond was comparable or lower in magnitude than those obtained in freshwater earthen ponds. The h2 estimates for body weight at harvest became more stable (range 0.13–0.20) when data from previous generations were included in the analysis. Including all data, the effect common to full-sibs (c2) accounted for 10% of the total phenotypic variance for body weight at harvest. Genetic correlation between growth recorded at expected time of sexual maturation and at harvest was 0.8, but seemed to decrease in later generations. The genetic correlations between growth in freshwater earthen ponds and other test environments were of similar magnitude. Breeding candidates in the base population (G0) were ranked according to their individual breeding values for growth (recorded as body weight at harvest), while those in later generations (G1–G5) were ranked according to a selection index including individual breeding values for growth and family breeding values for fillet yield. The selection response for growth was, on average, 11.4% per generation of selection (range 7.4–18.7%) when estimated based on control groups representing the parental generations. A genetic trend analysis based on all data (h2 =0.20, c2 =0.10) predicted an accumulated selection response of more than 200g and an average selection response of 8.0% per generation of selection when using the LS mean of the G0 as a base line for the comparison. The average inbreeding coefficient (F) was estimated to be 5.0% after six generations of selection. The results are discussed in a practical context of developing selective breeding programs for tilapias and it is concluded that the ongoing selective breeding of Nile tilapia in China has resulted in considerable genetic improvement of growth (60–90% larger body weight at harvest) after six generations of multi-trait selection. [Copyright &y& Elsevier]

To estimate genetic parameters of growth traits in Japanese flounder Paralichthys olivaceus, full-sib and half-sib families were produced in three consecutive years at the Beidaihe Central Experiment Station in China. Each year 8-28 families were produced. The body weight, body length and body depth at 180, 240, and 360 days of age were measured for 5,224 individuals. Four animal models were used to examine the phenotypic variation of growth traits and were compared using the likelihood ratio test. The results showed that estimates for additive genetic effect heritabilities varied greatly depending on the model, trait and age. The maternal effect had a significant impact on phenotypic variation only for body depth at 180 days of age, which explained 49% of the phenotypic variance. The ratio of full-sib effect to phenotypic variation ranged from 0.09 to 0.22. Growth traits all exhibited low heritability (0.13-0.39), indicating that there is the potential for family selection breeding for these traits in Japanese flounder. Using the full model with the fixed, full-sib family, additive and maternal genetic effects, genetic correlations among the three traits for fish of the same age were estimated to be more than 0.80. Generally, the genetic correlations gradually increased as age increased. [ABSTRACT FROM AUTHOR]

Abstract: Variance components and further phenotypic and genetic parameters for reproduction traits including litter size at birth (LSB) and at weaning (LSW), gestation period (GP) and litter weight at birth (LWB) were estimated by use of the MTGSAM procedure fitting two-trait animal model (y = X b + Z a a + Z P P + e ) in Boer dams. The calculations were based on 1205 parities of 435 Boer dams at Boer Goat Breeding Station in Yidu, China, during 2002–2007. Influencing factors such as parity and age of dam, kidding year and season, litter size at birth, sex of kids and some significant interactions were investigated as the fixed effects by PROC GLM (SAS8.1). The results showed that kidding year, parity and age of dam significantly influenced all the reproduction traits. Kidding season only affected the traits of GP and LWB. Litter size at birth had significant effect on LWB. The mean values of LSB, LSW, LWB and GP were 1.76±0.67, 1.62±0.62, 6.54±2.51 kg and 151.7±4.43 days. The estimates of direct additive heritability for above traits were 0.12±0.01, 0.10±0.01, 0.14±0.02 and 0.09±0.01, respectively. The estimates of all the correlations among LSB, LSW and LWB were higher than 0.52, and the genetic correlations were the highest among all the correlations. The estimates of genetic correlations between GP and other traits were medium (0.33–0.48) and lower than the permanent environmental correlations (0.60–0.72). In conclusion, compared with other goat breeds, the Boer goat has good characteristic in prolificacy. The gestation period is not significantly different in dams with increase of litter size, which is similar to the multiple birth species such as pig. However, the heritability estimates for all these reproduction traits obtained in the Boer dams are lower than 0.14; both LSB and LWB are traits with the highest heritability among 4 reproduction traits estimated. High genetic and permanent environmental correlations indicate that these traits were mainly attributable to different genetic effects or influenced by the permanent environmental effect for the different parity. [Copyright &y& Elsevier]

The razor clam Sinonovacula constricta , one of most important mariculture bivalve species in China, suffered from the variable challenges such as ammonia stress, drastic salinity fluctuation, highly variable temperature. Ammonia stress represents a common stressor and now considered to be the main limiting factor in intensive culture systems of S. constricta , a potential strategy for the challenge is selecting strain that are genetically resistant to the ammonia stress. Here, we constructed full-sib families and performed two challenge experiments in different life stages to estimate genetic parameters of ammonia tolerance and growth traits in S. constricta. A total of 45 families including 26 families at 5-month-old and 19 families at 10-month-old were used to test the ammonia tolerance, as well as the growth-related traits (Shell length, Shell height, Shell width and Body weight) of individuals. The heritability estimates of the two experiments were similar and comparable, moderate estimates were observed for heritability of ammonia tolerance (0.20 ± 0.07–0.28 ± 0.04), while moderate to high heritability (0.36 ± 0.13–0.64 ± 0.37) were found for growth-related traits. Slightly low genetic (0.34 ± 0.32–0.42 ± 0.30) and phenotypic (0.01 ± 0.05–0.15 ± 0.04) correlations were detected between ammonia tolerance and growth traits in the early life style, while the correlations were also low in genetic (0.13 ± 0.29–0.39 ± 0.25) and in phenotypic (0.03 ± 0.04–0.13 ± 0.04) in the later life style. These findings confirm the existence of genetic variation for ammonia tolerance and growth traits and provide important information to guide effective selection of S. constricta. • Heritabilities of ammonia tolerance were estimated by two challenge experiments in different growth stages in S. constricta. • Moderate heritability for ammonia tolerance indicates potential prospects for genetic improvement. • Correlation between ammonia tolerance and growth-related traits was low. • The heritabilities were in a moderate-to-high level and correlation were high among growth-related traits. [ABSTRACT FROM AUTHOR]

Selective breeding refers to the selection of individuals or populations with superior genetic traits from a population or family, for the purpose of directionally screening and enriching the dominant traits of the target species, to acquire breeds with directional dominant traits. The mandarin fish (Siniperca chuatsi) is an important high-quality freshwater fish widely cultured in China. The selective breeding of this species to obtain desirable growth performance traits has garnered considerable attention by researchers. We constructed a basic breeding population by selecting high growth as the target trait. Subsequently, we conducted family selection through four successive generations. We used the growth data (initial and harvest body weights) of the four generations of mandarin fish to estimate the realized heritability, selection response, and genetic gain, on the body weight of mandarin fish. We obtained the following values from generations F1–F4: realized heritability 0.17–0.47, selection response 0.40–1.12, and genetic gain 6.94–17.25%. The average genetic gain was 12.14%. Moreover, after four generations of breeding, the average growth rate of the selective breeding population had increased by 16.3% compared with that of the control group. This indicated that selective breeding had resulted in good genetic progress regarding the growth traits of mandarin fish and desirable selection effects. The coefficient of variation for the harvest body weight of generations F1–F4 decreased with increasing generation number (18.68–10.10%). This shows that the degree of variation in body weight among families decreased over generations, tending towards genetic stability after selective breeding. Our results provide a scientific basis and technical support for mandarin fish breeding and may serve as a reference for breeding other aquaculture species. • This is the first report of realized heritability, selection response, and genetic gain for growth traits in mandarin fish. • The realized heritability of growth traits was moderate in mandarin fish. • Good genetic progress has been achieved through the selective breeding of mandarin fish. [ABSTRACT FROM AUTHOR]

• The controlled pollination families of P. massoniana can obtain high genetic gain. • Genotype-environment interaction affects the growth of P. massoniana families. • Tested families include genotypes adapted to different environments. The Masson pine breeding programme has advanced to the third cycle. However, breeding and deployment are based largely on plantation inventory zones rather than biological patterns of genotype by environment interaction (G × E) and consequently cannot deliver optimal genetic gains across the whole plantation estate. The present study analysed G × E in family tests of Masson pine planted in the eastern and central regions of China. Twenty-six controlled pollination families were selected at three experimental sites. Measurements were performed at 8 years of age for diameter at breast height, total height, and volume. The genotype and G × E (GGE) biplot was used to study the effects of G × E, and the type B correlation coefficients was used to evaluate the extent of G × E. Significant site, family and family × site effects on growth traits were found (p < 0.05). Family heritability (h f 2) and individual heritability (h s 2) ranged from 0.59 to 0.84 and 0.16 to 0.38. The type B correlation refers to genetic correlation between different environments. In this study, type B correlation coefficients between tested sites were all less than 0.8, indicating significant G × E among families at different sites. The volume of family 6 was highest at the TZS and XJ sites, and that of family 4 was highest at the SW site. 12 superior families and 49 superior individual trees were selected, and, as determined by comparison with the controls, the real gain (G) of volume was 23.70% and 279.53%, respectively. At the three sites, the individual volumes of families 6, and 15 were larger and more stable than those of other families, while family 4 was large and unstable. The analyses revealed that those families that perform best in all the tests can be planted in areas with similar environmental traits to the sites tested here. Excellent genotypes with stable and high yield can provide a basis for follow-up breeding work. [ABSTRACT FROM AUTHOR]

A base population containing broad genetic variation provides a fundamental resource for a successful genetic improvement program. Here, we assess quantitative data on growth traits taken from the base population of Pacific white shrimp. Body weight was scored at two ages (BW1 and BW2) from 2752 and 2452 individuals, representing 89 full-sib families. Estimated heritabilities (h 2 ± SE) for BW1, BW2 and survival (S) were 0.52 ± 0.09, 0.44 ± 0.07, and 0.01 ± 0.02, respectively. The genetic correlation between growth traits (BW1 and BW2) was 0.95, a result significantly different from zero. Genetic correlations between survival and body weight were low however, 0.26 (S vs BW1) and 0.18 (S vs BW2), respectively. The SA_1 strain from South Asia showed the best performance for both growth rate and survival in the test tank systems. High heritability estimates for growth traits confirm that a substantial component of additive genetic variance is available for growth in our L. vannamei culture line families in China prior to imposing genetic selection to improve relative productivity. • In this paper we report genetic parameters for growth in penaeid shrimp breeding of sourcing founding population based on domesticated strains. • Quantitative data of 89 full sib-families confirm that a substantial component of additive genetic variance is available for growth in our L. vannamei lines prior to a family selection breeding program to improve relative productivity. • We believe that results presented here are important for sourcing base populations in genetic improvement of aquaculture species, particularly for targeting exotic species. [ABSTRACT FROM AUTHOR]

Lactose and somatic cell score (SCS) are major economic traits of milk. However, for many countries, they are typically not directly considered in the national genetic evaluation of Simmental cattle. This study aimed to estimate the genetic relationships between lactose, SCS, and growth traits of Simmental cattle to provide information for the national genetic evaluation of the selection of traits of this cattle population. The data of 1781 animals with 6519 records obtained over a period of 41 years (1975-2016) were collected from Xinjiang Hutubi Farm, China. The analyzed traits included 305 days of milk yield (305MY), milk fat percentage (MFP), milk protein percentage (MPP), milk lactose percentage (MLP), total solids (TS), SCS, body height (BH), body length (BL), chest girth (CG), abdominal circumference (AC), rump width (RW), rump length (RL), leg circumference (LC), and cannon circumference (CC). The multiple-trait repeatability model was adopted to estimate (co)variance components using the average information-restricted maximum likelihood method implemented using the DMU statistical package. The heritability estimates for milk components and growth traits ranged from 0.09 (SCS) to 0.51 (BH). Genetic correlations for milk components ranged from 0.03 ± 0.14 (MFP and MLP) to 0.81 ± 0.08 (MFP and MPP). Genetic correlation between MLP and SCS was moderate and negative (-0.50 ± 0.15) compared with that among other traits. Genetic correlations between the milk components and growth traits ranged from 0.00 ± 0.07 (305MY and RW) to -0.64 ± 0.15 (MLP and BL). Genetic correlations of BL, LC, RW, and RL with MLP were moderate to high and negative ranging from -0.39 to -0.64. Somatic cell score showed the highest correlation with BL (0.41) followed by LC (0.21). An increase in MLP would result in an increase in 305MY or TS and a decrease in BL, LC, RW, and RL. Additionally, a decrease in SCS would occur with the selection of increased MLP and reduced BL. We conclude that selection based on easily and inexpensively measured growth traits could improve the milk quality from Simmental cattle., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

The objective of this study was to estimate group- and breed-specific genetic parameters for reproductive traits in Chinese Duroc, Landrace, and Yorkshire populations. Records for reproductive traits between April 1998 and December 2017 from 92 nucleus pig breeding farms, which were involved in the China Swine Genetic Improvement Program, were analysed. Due to weak genetic connectedness across all farms, connectedness groups consisting of related farms were used. Three, two and four connectedness groups for Duroc, Landrace and Yorkshire were firstly established according to the genetic connectedness rating among farms. For each connectedness group a five-trait animal model was implemented, and via restricted maximum likelihood procedure the genetic parameters were estimated for five reproductive traits i.e., total number born (TNB), number born alive (NBA), litter weight at farrowing (LWF), farrowing interval (FI) and age at first farrowing (AFF). The average of heritabilities among connectedness groups ranged from .01 (for FI in Yorkshire) to .30 (for AFF in Duroc). Estimates of repeatability for litter traits ranged from .14 to .20 and were consistent for each breed, and for FI, the estimates varied from .01 to .11 across breeds and groups. The estimated genetic correlations among litter traits (i.e., TNB, NBA and LWF) were all significantly high (>.56) and similar across breeds. Averaged genetic correlations over three breeds were -.25, -.27, -.18, -.04, -.10, -.02, and .28 for FI-TNB, FI-NBA, FI-LWF, AFF-TNB, AFF-NBA, AFF-LWF and FI-AFF, respectively. The standard errors of the estimates were all very low (<0.01) in most situations. Results from this study suggest that selection based on TNB which is currently used in dam line selection index can improve NBA and LWF simultaneously. However, care should be taken on FI and AFF as they are both greatly influenced by non-genetic factors such as management and measurement., (© 2019 Blackwell Verlag GmbH.)