Use of a culture medium (McCoy®), as a method for evaluating Bos indicus × Bos taurus embryos

The aim of this study was to use culture medium (McCoy®) as a test to evaluate the classification of embryos after a primary grading using stereoscopic microscopy to further confirm whether embryos have been correctly scored by stereoscopic microscopy evaluating the level of apoptosis. Forty‐six Bos indicus embryos were collected with a non‐surgical method and evaluated with stereoscopic microscopy for scoring in three categories (good, fair and poor). Cell proliferation and apoptosis were assessed and compared between the control group (n = 14) at the onset of the experiment and in an experimental group (n = 32) after stored for 4 h in a culture medium. Embryos were processed using TUNEL and BrdU markers to determine the apoptosis and cell proliferation. Seventy‐four per cent of good quality embryos developed favourably after the 4 h of culture; 60% of fair embryos maintained their evolution, while 100% of poor quality embryos presented degenerative changes from the beginning. No statistical differences were found between the experimental and the control groups in the count of positive BrdU and apoptotic nuclei. In poor quality embryos, a higher number of apoptotic cells were found relative to good and fair embryos, both in the experimental and control groups (P < 0.05). These results suggest that the culture medium may be used for a short time as a fast, practical and non‐invasive alternative to further confirm whether embryos have been correctly scored by stereoscopic microscopy.     

野牦牛(Bos mutus)的生态适应性

本文介绍了野牦牛的分布及其生态条件,并且从体型、被毛、血液生理生化、血液蛋白多态性、血清同工酶、组织代谢类型等方面阐述野牲牛对高寒、缺氧生态环境的适应性.     

野牦牛（Bos mutus）的生态适应性

本文分析了野牦牛的分布及其生态条件，并且从体型，被毛，血液生理生化，血液蛋白多态性，血清同工酶，组织代谢类型等方面阐述野牦牛对高寒，缺氧生态环境的适应性。     

Absolute copy number differences of Y chromosomal genes between crossbred （Bos taurus x Bos indicus） and Indicine bulls

Background： The Y chromosome in mammal is paternally inherited and harbors genes related to male fertility and spermatogenesis. The unique intra-chromosomal recombination pattern of Y chromosome and morphological difference of this chromosome between Bos taurus and Bos indicus make it an ideal model for studying structural variation, especially in crossbred （Bos taurus x Bos indicus） bulls. Copy Number Variation （CNV） is a type of genomic structural variation that gives information complementary to SNP data. The purpose of this study was to find out copy number differences of four Y chromosomal spermatogenesis-related candidate genes in genomic DNA of crossbred and purebred Indicine bulls. Result： Four Y chromosomal candidate genes of spermatogenesis namely, sex determining gene on Ychromosome （SRY）, DEAD box po/ypeptide 3-Y chromosome （DDX3 Y）, Ubiquidn specific peptidase 9, Y-linked （ usPgY）, testis-specific protein on Y chromosome （TSPY） were evaluated. Absolute copy numbers of Y chromosomal genes were determined by standard curve-based quantitative real time PCR. Copy numbers of SRYand TSPYgenes per unit amount of genomic DNA are higher in crossbred than Indicine bulls. However, no difference was observed in DDX3Yand usPgYgene copy numbers between two groups. Conclusion： The present study demonstrates that the structural organization of Y chromosomes differs between crossbred and Indicine bulls which are reproductively healthy as observed from analysis of semen attributes. The absolute copy numbers of SRY and TSPY genes in unit mass of genomic DNA of crossbred bulls are significantly higher than Indicine bulls. No alteration in absolute copies ofDDX3Yand usPgYgene was found between the genome of crossbred and Indicine bulls. This study suggests that the DDX3Yand USPgYare likely to be single copy genes in the genome of crossbred and Indicine bulls and variation in Y chromosome length between crossbred and Indicine bulls may be due to the copy number variation of SRY gene and TSPYarray.     

Evaluation of candidate genotype of leptin gene associated with fertility and production traits in Hardhenu (Bos taurus × Bos indicus) cattle

The present study was conducted on Hardhenu cattle to screen genomic region of leptin gene with an objective to find the association of genotypes with fertility and production traits. The association analysis with traits under study was analysed by least squares analysis of variance by taking SNPs genotype as fixed effects in the statistical model. The genotypic frequencies with respect to targeted loci g.92450765 G > A indicated that AG (0.54) genotype was highest in Hardhenu cattle. Chi-squared tests showed that g.92450765G > A SNP meet with the Hardy–Weinberg equilibrium (p > .05).The association analysis revealed significant association of genotypes with total milk yield (TMY) and 305 days milk yield (MY) (p < .05). Service period (SP) and calving interval (CI) were also found significantly associated with genotypes (p < .05). Whereas, lactation length (LL), dry days (DD) and age at first calving (AFC) did not divulge any significant association with genotype. The AG and GG genotypes were associated with higher milk yields as compared to AA genotype, indicating that allele G was associated with superior milk performance. However, AA genotyped cattle found to be favourable with SP, CI and artificial insemination (AI) per conception compared to AG and GG genotyped cows. Chi-square analysis revealed that genetic variants of g.92450765 G > A SNP of leptin gene differ significantly with regard to reproductive disorders incidence (p < .05). The frequency of GG genotype (88.89%) in the affected animal group was very high followed by AG. The animals with GG genotype were found to be more susceptible to reproductive disorders as suggested by the higher odd ratio value (16.00) in logistic model. These observations and their differential association with the fertility and production traits can be utilized as an aid to selection for genetic improvement of antagonistic traits in dairy cows.     

大额牛(Bos frontalis)的生物学特征及研究开发利用潜力

大额牛(Gayal)仅分布于我国云南省西部高黎贡山的独龙江和怒江流域,以及印度的阿萨姆邦、东孟加拉、不丹和缅甸北部钦邦海波1500m以上的山区,是一种半家养半野生的珍稀动物。大额牛又称之为独龙牛,“独龙牛”一词来源于傈僳语“曲阿尼”,汉译为“独龙牛”,独龙族语将独龙牛叫为“阿布”,为体大有野性之意。     

Analysis of Two Chinese Yak(Bos grunniens) Population Using Bovine Microsatellite Primers

Two Chinese domestic yak populations representing the Plateau type and the Huanhu Alpine type were analysed with 12 bovine microsatellite primers. All primer pairs functioned in the yak genome and polymorphism was found at all loci. The allele size ranges and frequencies of the two yak populations were similar and there was considerable overlap with the allele size ranges observed in cattle. Data for European cattle breeds was obtained from the Cattle Diversity Database(CaDBase)to interpret the heterozygosity and genetic distance estimates in yak populations. Heterozygosity estimated for the two yak populations was comparable to that of European cattle while Nei's Genetic Distance DA between the two yak populations was less than distances between the most closely related German cattle breeds. Bovine microsatellite primers proved to be a valuable tool for characterization of yak populations.     

Comparison Study of Growth Performance,Nutrient Digestion,Rumen Fermentation and Blood Physiological Indexes between Yaks (Bos grunniens) and Cattle (Bos taurus) under Low-Concentrate Barn Fattening北大核心CSCD

This study was aimed to compare the growth performance, nutrient digestion, rumen fermentation and blood physiological indexes between yaks (Bos grunniens) and cattle (Bos taurus) under low-concentrate barn fattening, which provide data reference and technical support for breed and feeding technology selection of fattening beef cattle in the Qinghai-Tibetan Plateau. In this experiment, six healthy yaks [(211 ±6) kg] and six healthy Qaidam cattle [(210±7) kg], all castrated and 4 years of age, were selected and raised in individual metabolic cages. The experimental diets consisted of concentrate (2.0 kg / d per head) and forage (ad libitum) . The pre-experiment lasted for 10 days, and the trial lasted for 95 days. The results showed as follows: 1) total dry matter intake were significantly lower in yaks than cattle (P<0.05), whereas average daily gain was not different between yaks and cattle (P>0.05), therefore, feed / gain was significantly lower in yaks than cattle (P<0.05) . 2) There was no difference between yaks and cattle in apparent digestibilities of nutrients (P>0.05) . 3) Ruminal pH tended to be higher (P = 0.083), and the concentrations of iso-volatile fatty acids (VFAs) were significantly greater in yaks than cattle (P<0.05), whereas the concentrations of total volatile fatty acids (TVFA), acetate, propionate and butyrate were not significantly different between yaks and cattle (P>0.05) . 4) Concentrations of ammonia nitrogen, free amino acid nitrogen and soluble protein nitrogen in rumen were significantly greater in yaks than cattle (P<0.05) . 5) The red blood cells (RBC) amount, hemoglobin (HGB) content, hematocrit (HCT) and red blood cell volume distribution width (RDW-CV) were significantly lower (P < 0. 05), whereas mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) content and platelets (PLT) amount were significantly higher in yaks than cattle (P<0.05) . In conclusion, yaks have lower feed intake, but have a greater feed conversion efficiency than cattle, therefore, yaks can produce a greater economic benefits than cattle under low-concentrate barn fattening system. © 2023 Authors. All rights reserved.     

The Agersoe cattle: the last remnants of the Danish island cattle (Bos taurus)?

A phenotypically interesting strain of cattle existed on the small island of Agersoe, on the west coast of Zealand, Denmark, in the beginning of the last decade. The cattle share a great resemblance to the extinct Danish breed, the Island cattle. The objective of this study was to genetically characterize the Agersoe cattle, using microsatellites, amplified fragment length polymorphism (AFLP) and mtDNA markers, and analyse the genetic variability within the breed and the genetic relationship to 14 European breeds with focus on the Red Danish and Jutland breed. The results show diversity in nuclear markers comparable to that of modern breeds and that the Agersoe cattle are separable from the two native breeds. The absence of inbreeding and the degree of genetic diversity are taken as a sign of recent admixture. The Agersoe cattle did not exhibit a consistent association with any of the European breeds. Several arguments based on this survey have been put forward in favour of characterizing the Agersoe cattle as being the last remnants of the Danish Island Cattle.     

The major histocompatibility complex of West African cattle. Typing of lymphocyte antigens (BoLA) of Baoulé cattle (Bos taurus) and Sudanese zebus (Bos indicus) of Burkina Faso (West Africa)

Lymphocyte antigen (BoLA) typing on 247 Baoule cattle (Bos taurus) and 106 Sudanese zebus (Bos indicus), allowed us to determine gene frequencies of 43 class 1 specificities, as international "W" and European "EU", as African local from Kenya "KN" and Burkina Faso "BF". In comparing these frequencies, it appears that some specificities could be considered as significant breed markers for Baoule cattle and zebus.     

Seroprevalence of Brucella infection in yaks (Bos grunniens) on the Qinghai?CTibet plateau of China

The seroprevalence of Brucella infection in yaks was surveyed on the Qinghai-Tibet plateau of China in 2010. A total of 621 serum samples was collected from six counties and were tested by serum agglutination test. The results showed that 56 (9%) of the samples were positive for Brucella. The results of the present investigation indicate that brucellosis is common in yaks on the Qinghai-Tibet plateau of China.     

A Comparative Study on the Oestrous Response to PGF2α Analogue Treatment,and Conception Rates According to Time of Artificial Insemination,in Zebu (Bos indicus) and Baoulé (Bos taurus) Cattle

The oestrous response, interval and conception rates were studied after synchronization with a prostaglandin analogue (cloprostenol) and artificial insemination (AI) performed at different times in 50 Zebu (Bos indicus) and 83 Baoulé (Bos taurus) cattle indigenous to Burkina Faso. The overall proportion of cows responding to synchronization was 70% (93/133). Although the response was higher for the Baoulé cattle, at 73.5% (61/83), than for the Zebu, at 64% (32/50), the difference was not statistically significant (p>0.05). The mean oestrous interval from treatment to the onset of oestrus (TOI) was shorter in the Zebu (54.1 h, SD 6.7) than in Baoulé (65.2 h, SD 12.9) cattle (p<0.001). Of the Zebu (n = 32) that responded, 65.7% presented oestrus over a period of 12 h ranging from 48 h to 60 h after treatment. For the Baoulé cows, the highest proportion of animals in oestrus over a period of 12 h was 41% between 60 h and 72 h after treatment. The frequency distribution of onset of the oestrus indicated that up to 64.5% of the Zebu and 79.5% of the Baoulé cattle showed onset of oestrus during the daytime. For Zebu and Baoulé cows inseminated 13 h or 18 h after the onset of oestrus, conception rates were 56% and 57% (p>0.05) and 33% and 64% (p<0.05), respectively. Based on these findings, it appears that the oestrous response to synchronization was adequate for both Zebu and Baoulé cattle and that the time to onset of oestrus varied according to genotype. It was also concluded that conception rates were satisfactory for both genotypes but that, for Baoulé cattle, AI performed 18 h after oestrus significantly increased conception rates compared to AI at 13 h after oestrus.     

Effect of cow parity and synchronization method with PGF2α on conception rates of Bos indicus cows in Cameroon

The objective of this work was to evaluate the effect of two synchronization methods with prostaglandins F2α (PGF2α) on heifers and multiparous cows. Fourty-three Bos indicus cows (white and Red Fulani) were divided into four groups in a two-by-two factorial structure, parity x method of synchronization. The synchronization methods consisted of a two-dose regime which involved injection of animals on day 0 with PGF2α (Lutalyse) at 5 ml per cow intramuscularly. On day 11, the injection was repeated at the same dosage. On day 14 (72 h after the second injection), a fixed-time artificial insemination (AI) was done. On day 15 (96 h after the second injection), a second insemination was done. The one-and-a-half-dose regime consisted of an injection similar to the first treatment mentioned above on day 0. Thereafter, cows were observed for heat, and anyone showing heat was inseminated. A second dose was given on day 11 to all animals not having shown any heat. A fixed-time AI was done on days 14 and 15. Blood samples were collected on the day 0 of insemination for each cow while day 11 and day 21 after insemination. Progesterone was analysed by means of standard ELISA progesterone kits to determine its profiles after insemination. Results show no evidence of the effect of treatments on conception rates (P?>?0.05). Similarly, heifers and multiparous cows had similar conception rates (P?>?0.05). Between 3 weeks and 3 months of pregnancy, there was a loss of embryos of 28 % in heifers and 20 % in multiparous cows, but the difference between the two groups was not significant (P?>?0.05). It recommended that farmers do not synchronize animals with poor body condition score (BCS). They should also monitor weight gains of heifers, remove them from the herd when they have been mixed with young growing bulls and put them in a breeding herd. The two-dose regime is better to be used in areas where the inseminator cannot easily be available.

     

Do cattle (Bos taurus) retain an association of a visual cue with a food reward for a year?

Use of visual cues to locate specific food resources from a distance is a critical ability of animals foraging in a spatially heterogeneous environment. However, relatively little is known about how long animals can retain the learned cue–reward association without reinforcement. We compared feeding behavior of experienced and naive Japanese Black cows (Bos taurus) in discovering food locations in a pasture. Experienced animals had been trained to respond to a visual cue (plastic washtub) for a preferred food (grain‐based concentrate) 1 year prior to the experiment, while naive animals had no exposure to the cue. Cows were tested individually in a test arena including tubs filled with the concentrate on three successive days (Days 1–3). Experienced cows located the first tub more quickly and visited more tubs than naive cows on Day 1 (usually P < 0.05), but these differences disappeared on Days 2 and 3. The performance of experienced cows tended to increase from Day 1 to Day 2 and level off thereafter. Our results suggest that Japanese Black cows can associate a visual cue with a food reward within a day and retain the association for 1 year despite a slight decay.     

Effect of protein supplementation on reproductive and productive performance in <Emphasis Type="Italic">Bos indicus</Emphasis> × <Emphasis Type="Italic">Bos taurus</Emphasis> heifers raised in the humid tropics of Costa Rica

In order to evaluate the effect of protein supplementation on the productive and reproductive performance of heifers, 45 Bos indicus × Bos taurus heifers, 673 ± 146 days of age and weighing about 340 kg, were divided into two groups. The control group (n = 23) continued without supplementation, but the supplemented group (SG; n = 22) received concentrate at a rate of 1% BW kg per day. Animals were adapted to the concentrate over a 15-day period and then supplemented for 30 days, after which estrus was synchronized using a progesterone implant. Back fat thickness (BFT) was assessed by ultrasound. The SG had better average daily weight gain than the nonsupplemented group (0.63 ± 0.16 vs. 0.51 ± 0.13 kg/day, P < 0.05) and tended to show a better percentage ovulation (P < 0.10, 77% vs. 57%, respectively). However, this tendency was not reflected in the final pregnancy rates. No differences were observed between groups in dry matter intake and body condition scores. SG with a high BFT (>0.70 cm) showed a better ovulation percentage than those with low BFT (<0.69 cm; P < 0.01). Additionally, the pregnancy rate of supplemented heifers with high BFT tended to be better than heifers with low BFT in this same group (67% vs. 30%, respectively, P < 0.10). It is concluded that protein supplementation improved reproductive performance and that ultrasonography to measure BFT may be used to estimate reproductive performance.     

The effect of the control of endo- and ectoparasites on weight gains in crossbred cattle (<Emphasis Type="Italic">Bos taurus taurus</Emphasis> × <Emphasis Type="Italic">Bos taurus indicus</Emphasis>) in the central region of Brazil

Endo- and ectoparasite infections are among the most important causes of disease and production losses in beef cattle in tropical and subtropical regions. Nevertheless, most treatments are given without epidemiological information and without evaluating their effect on the development of the animals. In this work we present the results of a study of the effect of treatments against endo- and ectoparasites in crossbred steers, during three cycles of field trials in the Brazilian Cerrado region. Three anthelmintic treatments during the winter and three acaricidal treatments during the spring/summer provided significant additional weight gain in three and two experimental trials, respectively. In the trials, steers treated for gastrointestinal nematodes gained a mean of 33 kg more and those treated for ectoparasites had additional mean weight gains of 13 kg compared with non-treated steers.     

Human–animal interaction,stress, and embryo production in <Emphasis Type="Italic">Bos indicus</Emphasis> embryo donors under tropical conditions

This study investigated the effect of human–animal interaction (HAI) and the stress response on the quality of embryo production in superovulated Nelore (Bos indicus) cattle, under tropical conditions. Thirty-two females underwent a superovulation protocol for 5 days. Cortisol concentrations were determined in blood plasma collected on days 0, 4, and 5. Artificial insemination was performed on days 4 and 5, and nonsurgical embryo flushing on day 11. Embryo production and viability were determined. Human stimulation, animal behaviors, accidents, and handling time were recorded to assess HAI. Cattle age was negatively correlated with accidents, frequency of aversive behaviors, and negative stimuli by stockperson during transit through corral compartments to receive superovulation treatments. The factor analysis revealed two distinct groups. The first group was called stressed and had higher cortisol concentration than the nonstressed group, 16.0 ± 2.1 and 12.5 ± 1.0 ng/mL, respectively. Comparisons between these groups showed that the frequency of voice emissions by the stockperson and the number of accidents were higher in the stressed group, and also, the mean handling time was longer in the stressed group than for the nonstressed. As a result, viability rate of the embryos was 19% lower in the stressed group (P < 0.05). This indicates that intensive negative HAI is likely related to stress, which affects embryo production in a superovulation program.