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1.
PLoS One ; 16(10): e0257249, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34648524

RESUMO

OBJECTIVES: Antibiotics are important for improving animal health and production. However, the deposition of its residues in food of animal origin intended for human consumption at non-permissible levels has generated global health concern and the need to tackle this using the "One Health Approach". This study assessed the knowledge and practice of 286 cattle handlers in Kwara State, Nigeria. METHODS: A web-based cross sectional online survey using a semi-structured questionnaire was conducted from November to December, 2019. Univariate, bivariate and multivariate analyses were performed at 95% confidence interval to determine predictors of good knowledge and practices towards Antibiotic Residues in Meat and Milk among cattle handlers. RESULTS: This study revealed that majority (52.7% n = 165/286) of the cattle handlers were not aware of antibiotic residues. Knowledge and practices regarding antibiotic residues were generally poor among the study population; 36.7% and 35.5% had satisfactory knowledge and practice respectively. The age (p = 0.026), gender (p = 0.006) and business duration (p = 0.001) of participants were significantly associated with their knowledge of antimicrobial residues. The effect of education on knowledge was modified by age. The odds of having poor knowledge on antibiotic residues increased 4 times among participants who were ≤40 years old than those above 40 years (Stratum Specific OR = 3.65; CI = 1.2, 11.1; p = 0.026). Knowledge levels of participants were statistically associated with their practice levels p<0.05 (OR = 2.43; CI = 1.45. 4.06; p = 0.0006). CONCLUSION: This implies that poor knowledge is a risk factor to having poor practice among cattle handlers. Deliberate efforts towards educating cattle farmers on best farm practices in antibiotic use would prevent antibiotic residues in meat and milk. Also, an effective surveillance system for monitoring the use of veterinary drugs in Kwara State, Nigeria is crucial.


Assuntos
Criação de Animais Domésticos , Antibacterianos/análise , Bovinos , Fazendeiros , Leite/química , Carne Vermelha/análise , Adulto , Animais , Bovinos/fisiologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Nigéria , Drogas Veterinárias/análise
2.
Semina Ci. agr. ; 42(05): 3057-3063, set.-out. 2021. tab
Artigo em Inglês | VETINDEX | ID: vti-764913

RESUMO

The goal of this study was to evaluate the rejection rates of Zebu bulls during behavioral assessment (libido and serving ability) and the importance of this step in bull breeding soundness evaluation (BBSE). A totalof 1,534 bulls reared in the state of Rio Grande do Sul, Brazil, of Nelore (1,340), Brahman (76), Guzerá (98), and Tabapuã (210) breeds were evaluated. The evaluation consisted of four steps. Step I was the general physical examination, Step II genital tract examination, Step III semen evaluation, and Step IV behavioral assessment of libido and the ability to complete copulation. To evaluate the relationship between the binary variables of approved or rejected during different steps of the BBSE, and age groups (young and mature bulls), chi-square tests and logistic regression were used. The general rejection rates in the BBSE were 5.64% and 15.20% for young and mature Zebu bulls, respectively. Problems with the sexual behavior (libido and/or serving ability) of bulls accounted for the rejection of 0.46% and 2.29% of young and mature Zebubulls, respectively. The lack of libido and serving ability was shown to be an important problem concerning the total number of possible causes of Zebu bull rejection during the BBSE. This result suggests that the behavioral step should be performed regularly, rather than being complementary to the standard BBSE in Zebu cattle.(AU)


O objetivo deste estudo foi avaliar as taxas de reprovação de touros zebuínos durante a avaliação comportamental (libido e habilidade física) e a importância desta etapa no Exame Andrológico em Touros (EAT). Foram avaliados 1.534 touros, criados no estado do Rio Grande do Sul, Brasil, das raças Nelore(1.340), Brahman (76), Guzerá (98) e Tabapuã (210). A avaliação constou de quatro etapas. Etapa I foi o exame físico geral, Etapa II o exame do trato genital, Etapa III a avaliação do sêmen, e a Etapa IV a avaliação comportamental de libido e habilidade física para completar a cópula. Para avaliar a relação entre a variável binária aprovado ou reprovado durante as diferentes etapas do exame andrológico e as faixas etárias (touros jovens e adultos), foram utilizados os testes de qui-quadrado e de regressão logística. As taxas gerais de reprovação no EAT foram de 5,64% e 15,20% para os touros Zebu jovens e adultos, respectivamente. Problemas no comportamento sexual (libido e/ou habilidade física) dos touros foram responsáveis pela reprovação de 0,46% e 2,29% dos touros zebuínos jovens e adultos, respectivamente. A falta de libido e de habilidade física mostrou-se um problema importante em relação ao número total de possíveis causas de reprovação de touros zebuínos no EAT. Esse resultado sugere que a etapa comportamental deve ser realizada regularmente, ao invés de ser apenas complementar ao EAT padrão em bovinos zebuínos.(AU)


Assuntos
Animais , Masculino , Bovinos , Bovinos/fisiologia , Comportamento Sexual Animal/fisiologia , Libido/fisiologia , Andrologia
3.
BMC Vet Res ; 17(1): 311, 2021 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-34563192

RESUMO

BACKGROUND: Metabolic profile evaluation is a tool widely used in ruminant nutrition as metabolic cues that relate nutrition to physiology. Metabolic and hormonal traits change during pre-partum and lactation according to parity in dairy cows, but studies of beef cows under grazing are scarce. The present study aimed to evaluate how metabolic and hormonal traits change over time, their relationship to performance, and determine if these factors differ according to the parity order of grazing beef cows. Thirty-six pregnant Nellore cows (12 nulliparous, 12 primiparous, and 12 multiparous) were used. The study started at 60 d prepartum until 203 d of lactation. RESULTS: The initial body weight (BW) and final BW were higher for multiparous cows (P > 0.05). An interaction occurred between parity and day (P < .0001) for body condition score. Nulliparous and primiparous body condition score were reduced from - 60 prepartum to 30 postpartum, then stabilized 60 postpartum (P < 0.05), while multiparous maintained body condition score from - 60 days until 60 days postpartum (P > 0.05). Calf BW, final BW, and average daily gain did not differ between parities (P > 0.05). Effect of day (P < 0.05) was detected for non-esterified fatty acids, triglycerides, total cholesterol, LDL, VLDL, progesterone, and insulin. An interaction was observed between parity and days for glucose, HDL, ß-hydroxybutyrate, creatinine and IGF-1 (P < 0.05). Parity affected serum urea nitrogen, total proteins, albumin, and globulins (P < 0.05). Parity and day relative to calving did not impact total T3 and T4 (P > 0.05). CONCLUSIONS: Hormonal and metabolic profile is strongly influenced by the stage of lactation. Time effects (pre-partum and lactation period) were more pronounced in nulliparous since they displayed more unbalanced metabolic and hormonal traits and lowered BCS pre- and postpartum.


Assuntos
Bovinos/sangue , Bovinos/fisiologia , Metabolismo Energético/fisiologia , Hormônios/sangue , Paridade/fisiologia , Animais , Peso Corporal/fisiologia , Feminino , Lactação , Gravidez
4.
PLoS One ; 16(8): e0248453, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34370740

RESUMO

The aim of this study was to determine the association between concentrations of progesterone (P4) during previous the estrous cycle with the intensity of spontaneous or estrogen-induced estrous expression and pregnancy per artificial insemination (P/AI). A total of 1,953 AI events from lactating Holstein cows were used, consisting of 1,289 timed AI events from experiment 1 (Exp. 1) and 664 AI events from experiment 2 (Exp. 2). In Exp. 1, cows were bred after a timed AI protocol based on estradiol and P4. In Exp. 2 animals were bred upon spontaneous estrus detection. In both experiments cows were continuously monitored by an automated activity monitor (AAM), in Exp.1 a relative increase of activity was calculated (i.e., percentage of increase activity at estrus compared to cow's baseline activity) and in Exp.2, activity data from each cow were computed into an index value that ranged from 0 to 100. In Exp.2 duration (hours) of estrus were calculated and defined as the total time above the threshold (35 index). The intensity of estrous expression was determined for each event and classified as either high or low intensity using the median of each experiment. Blood samples were collected for P4 analysis in Exp. 1 at -4 d, 0 d, and 7 d relative to timed AI, and in Exp. 2 immediately following estrus (0 d), 7 d, 14 d, and 21 d post-AI. Concentration of P4 was classified as greater or lower according to the median value in each experiment. Cows with lower concentrations of P4 at AI had greater estrous expression in Exp. 1 (363.6 ± 5.2 vs. 275.9 ± 8.0% relative increase) and Exp. 2 (76.7 ± 1.9 vs. 67.4 ± 4.7 index; and 12.5 ± 0.5 vs. 9.3 ± 1.8 hours). Cows with a greater intensity of estrous expression at timed AI had greater concentrations of P4 at -4 d than cows with lower intensity estrus or no estrous expression (4.6 ± 0.2 vs. 3.6 ± 0.2 vs. 3.7 ± 0.2 ng/mL). Cows with greater concentrations of P4 at -4 d had greater P/AI (32.8 ± 4.4 vs. 22.4 ± 4.5%), whereas cows with lesser concentrations of P4 at d0 for either timed AI (35.2 ± 3.4 vs. 19.6 ± 4.6%) or spontaneous estrus (31.8 ± 2.8 vs. 23.4 ± 3.2%) had greater P/AI. Cows with greater concentrations of P4 7 d post-timed AI had greater P/AI compared with cows that had lower concentration of P4 (39.1 ± 2.9 vs. 24.7 ± 2.6%). Similarly, cows that had lower concentrations of P4 at 7 d, 14 d and 21 d post-spontaneous estrus tended to have lower P/AI when compared with cows with greater concentrations of P4. Overall, concentrations of P4 prior to and at AI were associated with greater estrous intensity and P/AI at both spontaneous and timed AI events.


Assuntos
Bovinos/fisiologia , Ciclo Estral/sangue , Estro/sangue , Fertilidade/fisiologia , Progesterona/sangue , Animais , Bovinos/sangue , Ciclo Estral/fisiologia , Estro/fisiologia , Sincronização do Estro , Feminino , Inseminação Artificial/veterinária , Gravidez
5.
BMC Vet Res ; 17(1): 287, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34454480

RESUMO

BACKGROUND: Lactating dairy cows are the greatest livestock contributor of methane, a major global greenhouse gas (GHG). However, good feeding management with adequate mineral intake can offers an effective approach to maintaining high levels of milk production and the health of dairy cows over the entire course of lactation, while also helping to reduce methane emission. The study described here investigated the plasma concentrations of both macroelements (Ca, Na, K, Mg, P) and microelements (Zn, Cu, Fe, Mn), as well as enteric methane emission and milk composition in high-yielding dairy cows in different lactation periods. The experiment was performed on Holstein-Friesian dairy cows with the average milk yield of 41 (± 9) L/day in a Polish commercial farm with modern dairy systems. A total of thirty high-yielding dairy cows were randomly assigned into three groups differing by lactation stage: early stage (Early, days 25-100), middle stage (Middle, days 101-250), and late stage (Late, day 250 and later). Dietary treatment for all cows was a total mixture ration (TMR) with maize and alfalfa silage the main forage components. RESULTS: The greatest milk yield and methane production were recorded in early-stage lactating cows, but the greatest methane intensity per kg of corrected milk was recorded in the late stage of lactation. Plasma concentrations of macroelements and microelements did not differ by lactation stages, but increased plasma concentrations of Zn and Fe and decreased plasma levels of Mg were noted during lactation. A positive correlation was found between plasma levels of Mg and other macroelements (Ca, Na, K), and between the concentrations of Fe and Zn, P in plasma, but no correlation between methane emission and mineral status was detected in the different lactation stages. CONCLUSIONS: Our results showed different mineral requirements and enteric methane emissions in each lactation stage. The feeding strategy and mineral utilization were adequate to maintain the health, mineral status, and milk production of the Holstein cows during the entire lactation period, and suggest an effective way of reducing methane emission.


Assuntos
Bovinos/fisiologia , Lactação/fisiologia , Metano/biossíntese , Animais , Bovinos/metabolismo , Indústria de Laticínios , Dieta/veterinária , Feminino , Leite/química , Minerais/sangue
6.
Genes (Basel) ; 12(6)2021 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-34203058

RESUMO

The existing research on dairy cow mammary gland genes is extensive, but there have been few reports about dynamic changes in dairy cow mammary gland genes as milk yield decrease. For the first time, transcriptome analysis based on short time-series expression miner (STEM) and histological observations were performed using the Holstein dairy cow mammary gland to explore gene expression patterns in this process of decrease (at peak, mid-, and late lactation). Histological observations suggested that the number of mammary acinous cells at peak/mid-lactation was significantly higher than that at mid-/late lactation, and the lipid droplets area secreted by dairy cows was almost unaltered across the three stages of lactation (p > 0.05). Totals of 882 and 1439 genes were differentially expressed at mid- and late lactation, respectively, compared to peak lactation. Function analysis showed that differentially expressed genes (DEGs) were mainly related to apoptosis and energy metabolism (fold change ≥ 2 or fold change ≤ 0.5, p-value ≤ 0.05). Transcriptome analysis based on STEM identified 16 profiles of differential gene expression patterns, including 5 significant profiles (false discovery rate, FDR ≤ 0.05). Function analysis revealed DEGs involved in milk fat synthesis were downregulated in Profile 0 and DEGs in Profile 12 associated with protein synthesis. These findings provide a foundation for future studies on the molecular mechanisms underlying mammary gland development in dairy cows.


Assuntos
Bovinos/genética , Lactação , Glândulas Mamárias Animais/metabolismo , Transcriptoma , Animais , Bovinos/fisiologia , Metabolismo Energético , Feminino
7.
Pol J Vet Sci ; 24(2): 225-233, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34250771

RESUMO

This study details the relationship between maternal plasma oxidant-antioxidant enzymes with colostrum quality, serum gamma glutamyl transferase (GGT), immunoglobulin G (IgG) and IgM concentrations of calves in the different calving seasons. Holstein breed cows between two and eight lactations and their calves were enrolled in the study. Holstein cows calving in winter (n=45) and their calves (n=45) were assigned to the winter group, while cows calving in summer (n=45) and their calves (n=45) were assigned to the summer group. Samples for malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) were collected on day -21±3 before expected calving and also on calving day (Day 0). IgG and the specific gravity of the colostrum were determined after calving. Serum GGT and IgG and IgM were measured before the feeding, with colostrum, of calves (0 hours) and also in the 24th hour following the feeding of colostrum. Plasma MDA levels at -21±3 and 0 days in the summer cows were determined to be higher. GSH-Px activity was higher in the winter cows. IgG levels and the specific gravity of the colos- trum were also higher in the winter cows. Calf IgG levels at the 24th hour of life were higher in the winter cows. In the winter group, IgM levels at 0 and 24 hours were also higher. While MDA was negatively correlated with IgG, IgM, GGT, IgG and the specific gravity of colostrum, GSH-Px activity had a positive correlation with IgG, IgM, GGT, IgG and the specific gravity of colostrum. The observed differences in plasma MDA, GSH-Px, calf serum IgG and IgM levels, and colostrum quality between both groups suggest a possible seasonal effect. The relationship between maternal oxidant-antioxidant enzymes, colostrum quality, and passive calf immunity revealed that these enzymes could be used as indicators in the evaluation of calf health and colos- trum quality.


Assuntos
Antioxidantes/metabolismo , Bovinos/fisiologia , Colostro/fisiologia , Imunidade Materno-Adquirida/fisiologia , Estresse Oxidativo/fisiologia , Estações do Ano , Animais , Feminino , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Parto , Gravidez , gama-Glutamiltransferase/sangue , gama-Glutamiltransferase/metabolismo
8.
PLoS One ; 16(7): e0253479, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34288912

RESUMO

The aim of this study is to describe the kinematic gait characteristics of straight line walk in clinically sound dairy cows using body mounted Inertial Measurement Units (IMUs) at multiple anatomical locations. The temporal parameters used are speed and non-speed normalized stance duration, bipedal and tripedal support durations, maximal protraction and retraction angles of the distal limbs and vertical displacement curves of the upper body. Gait analysis was performed by letting 17 dairy cows walk in a straight line at their own chosen pace while equipped with IMU sensors on tubera sacrale, left and right tuber coxae (LTC and RTC), back, withers, head, neck and all four lower limbs. Data intervals with stride by stride regularity were selected based on video data. For temporal parameters, the median was calculated and 95% confidence intervals (CI) were estimated based on linear mixed model (LMM) analysis, while for limb and vertical displacement curves, the median and most typical curves were calculated. The temporal parameters and distal limb angles showed consistent results with low variance and LMM analysis showed non-overlapping CI for all temporal parameters. The distal limb angle curves showed a larger and steeper retraction angle range for the distal front limbs compared with the hind limbs. The vertical displacement curves of the sacrum, withers, LTC and RTC showed a consistent sinusoidal pattern while the head, back and collar curves were less consistent and showed more variation between and within cows. This kinematic description might allow to objectively differentiate between normal and lame gait in the future and determine the best anatomical location for sensor attachment for lameness detection purposes.


Assuntos
Bovinos/fisiologia , Marcha/fisiologia , Caminhada/fisiologia , Animais , Fenômenos Biomecânicos , Feminino , Coxeadura Animal/diagnóstico , Coxeadura Animal/fisiopatologia , Dispositivos Eletrônicos Vestíveis/veterinária
9.
PLoS One ; 16(7): e0255153, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34310659

RESUMO

Sustainability in livestock farming requires monitoring of autochthonous breeds which are well adapted to the local environment. The morphometric measurements seem to be the first approach which can provide useful information on the suitability of animal genetic resources for selection. In this work, thirteen morphometric variables were used for the phenotypic characterization of 130 adult autochthones cattle randomly selected from 30 local farms in Guelma. There were cases from four commonly accepted and traditional ecotypes: Guelmois, Cheurfa, Sétifien and Fawn. The results showed several and significant positive correlations between the different variables. Correlations were analyzed using Varimax orthogonal rotation PCA and three factors were extracted, which explain more than 75% of the total variation in the four ecotypes. Stepwise discriminant analysis showed that 6 of the 13 variables had discriminatory power to define the phenotypic profile of the ecotypes. Canonical discriminant analysis indicated that the Sétifien ecotype is separate from the other three ecotypes. Mahalanobis distances were significant between the different ecotypes except for the distance between the Guelmois and Fawn ecotypes. The cross-validation procedure assigned 91.42% of the Sétifien animals to their genetic group, while the percentages of animals assigned to the Cheurfa, Guelmois and Fawn ecotypes were 80.00%, 65.71% and 53.33% respectively. The multivariate approach has proven to be effective in differentiating the four ecotypes, with clear morphological differences from the Sétifien ecotype that may benefit from a genetic improvement program for more sustainable genetic resources preservation.


Assuntos
Bovinos/anatomia & histologia , Argélia , Animais , Bovinos/fisiologia , Análise Discriminante , Ecótipo , Cornos/anatomia & histologia , Cornos/fisiologia , Análise Multivariada , Análise de Componente Principal , Tórax/anatomia & histologia , Tórax/fisiologia
10.
BMC Vet Res ; 17(1): 255, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34311720

RESUMO

BACKGROUND: During maturation, spermatozoa acquire motility and fertilizing capacity as they transit through the epididymis. In recent years, two-dimensional gel electrophoresis has been employed in proteomics studies conducted in rat, boar and human. However, there has not been a complete information regarding the proteins associated with sperm maturation in the epididymis. In this study, we employed iTRAQ proteomics to investigate proteins associated with sperm maturation between yak and cattleyak epididymis. RESULTS: After a successful sampling and protein extraction, the iTRAQ coupled with LC-MS/MS mass spectrometry and bioinformatics analysis were performed. We identified 288 differentially abundant proteins (DAPs) between yak and cattleyak epididymis; 151 were up-regulated while 137 were down-regulated in cattleyak relative to yak. Gene Ontology analysis identified that down-regulated DAPs in cattleyak were mostly enriched in the acetylation of protein component, along with negative and positive regulatory activities. iTRAQ proteomics data showed that the top up-regulated DAPs were mainly enriched in cell communication, cell adhesion, cytoskeleton organization, stress response, post-translational modifications and metabolic functions while the down-regulated DAPs were predominantly associated with sperm maturation, long-term sperm storage, sperm forward motility, sperm-oocyte fusion and regulatory functions. CONCLUSION: These results provide insight into the molecular mechanisms underlying male cattleyak sterility.


Assuntos
Bovinos/genética , Bovinos/fisiologia , Epididimo/fisiologia , Maturação do Esperma/fisiologia , Espermatozoides/fisiologia , Animais , Regulação para Baixo , Masculino , Mapas de Interação de Proteínas , Proteômica , Regulação para Cima
11.
Reprod Domest Anim ; 56(10): 1329-1341, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34324738

RESUMO

The objectives of this study were to assess alterations in, echogenic appearance, size and blood flow in the corpus luteum, the placentomes and the blood flow in umbilical and uterine arteries that heat stress can cause in cooled pregnant dairy cows. Pregnant cows were allocated in two groups and the gravid uteri, along with the ipsilateral corpora lutea were examined during the winter (group W, n = 9) or the summer (group S, n = 10). The grey-scale ultrasound and colour flow imaging of the corpus luteum and placentome were performed. In addition, the umbilical and uterine artery diameters and haemodynamic parameters in the vessels were calculated. At the time of ultrasonographic examination, cortisol concentrations were higher, and progesterone levels tended to be lower in group S compared to group W. The grey-scale ultrasound evaluation of corpora lutea and placentomes was lower in group S compared to group W. The diameter of umbilical artery and the blood volume in the vessel were less in group S than in group W. We infer that heat stress affects foetal blood supply and possibly the structure of placentomes and corpora lutea, but it differently affects the blood flow characteristics in the umbilical and uterine arteries.


Assuntos
Bovinos/fisiologia , Corpo Lúteo/diagnóstico por imagem , Resposta ao Choque Térmico/fisiologia , Útero/diagnóstico por imagem , Animais , Feminino , Placenta/irrigação sanguínea , Placenta/diagnóstico por imagem , Gravidez , Estações do Ano , Ultrassonografia/veterinária , Artérias Umbilicais/diagnóstico por imagem , Artéria Uterina/diagnóstico por imagem , Útero/irrigação sanguínea
12.
Front Immunol ; 12: 620847, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34248929

RESUMO

Ticks cause substantial production losses for beef and dairy cattle. Cattle resistance to ticks is one of the most important factors affecting tick control, but largely neglected due to the challenge of phenotyping. In this study, we evaluate the pooling of tick resistance phenotyped reference populations from multi-country beef cattle breeds to assess the possibility of improving host resistance through multi-trait genomic selection. Data consisted of tick counts or scores assessing the number of female ticks at least 4.5 mm length and derived from seven populations, with breed, country, number of records and genotyped/phenotyped animals being respectively: Angus (AN), Brazil, 2,263, 921/1,156, Hereford (HH), Brazil, 6,615, 1,910/2,802, Brangus (BN), Brazil, 2,441, 851/851, Braford (BO), Brazil, 9,523, 3,062/4,095, Tropical Composite (TC), Australia, 229, 229/229, Brahman (BR), Australia, 675, 675/675, and Nguni (NG), South Africa, 490, 490/490. All populations were genotyped using medium density Illumina SNP BeadChips and imputed to a common high-density panel of 332,468 markers. The mean linkage disequilibrium (LD) between adjacent SNPs varied from 0.24 to 0.37 across populations and so was sufficient to allow genomic breeding values (GEBV) prediction. Correlations of LD phase between breeds were higher between composites and their founder breeds (0.81 to 0.95) and lower between NG and the other breeds (0.27 and 0.35). There was wide range of estimated heritability (0.05 and 0.42) and genetic correlation (-0.01 and 0.87) for tick resistance across the studied populations, with the largest genetic correlation observed between BN and BO. Predictive ability was improved under the old-young validation for three of the seven populations using a multi-trait approach compared to a single trait within-population prediction, while whole and partial data GEBV correlations increased in all cases, with relative improvements ranging from 3% for BO to 64% for TC. Moreover, the multi-trait analysis was useful to correct typical over-dispersion of the GEBV. Results from this study indicate that a joint genomic evaluation of AN, HH, BN, BO and BR can be readily implemented to improve tick resistance of these populations using selection on GEBV. For NG and TC additional phenotyping will be required to obtain accurate GEBV.


Assuntos
Cruzamento , Bovinos/genética , Resistência à Doença/genética , Genoma , Genômica/métodos , Infestações por Carrapato/veterinária , Carrapatos/fisiologia , Animais , Brasil , Bovinos/fisiologia , Feminino , Genótipo , Desequilíbrio de Ligação , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , África do Sul , Infestações por Carrapato/genética
13.
Genet Sel Evol ; 53(1): 60, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34261443

RESUMO

BACKGROUND: Managing beneficial Mendelian characteristics in dairy cattle breeding programs implies that the correlated genetic effects are considered to avoid possible adverse effects in selection processes. The Mendelian trait polledness in cattle is traditionally associated with the belief that the polled locus has unfavorable effects on breeding goal traits. This may be due to the inferior breeding values of former polled bulls and cows in cattle breeds, such as German Simmental, or to pleiotropic or linkage effects of the polled locus. METHODS: We focused on a variance component estimation approach that uses a marker-based numerator relationship matrix reflecting gametic relationships at the polled locus to test for direct pleiotropic or linked quantitative trait loci (QTL) effects of the polled locus on relevant traits. We applied the approach to performance, health, and female fertility traits in German Simmental cattle. RESULTS: Our results showed no evidence for any pleiotropic QTL effects of the polled locus on test-day production traits milk yield and fat percentage, on the mastitis indicator 'somatic cell score', and on several female fertility traits, i.e. 56 days non return rate, days open and days to first service. We detected a significant and unfavorable QTL effect accounting for 6.6% of the genetic variance for protein percentage only. CONCLUSIONS: Pleiotropy does not explain the lower breeding values and phenotypic inferiority of polled German Simmental sires and cows relative to the horned population in the breed. Thus, intensified selection in the polled population will contribute to increased selection response in breeding goal traits and genetic merit and will narrow the deficit in breeding values for production traits.


Assuntos
Bovinos/genética , Fertilidade/genética , Cornos/crescimento & desenvolvimento , Lactação/genética , Locos de Características Quantitativas , Adiposidade/genética , Animais , Bovinos/fisiologia , Feminino , Pleiotropia Genética , Estudo de Associação Genômica Ampla , Masculino , Modelos Genéticos , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Seleção Artificial
14.
Reprod Domest Anim ; 56(10): 1286-1292, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34251715

RESUMO

Pregnancy in cattle is the outcome of the complex process of initiation of cycling, fertilization, maternal recognition of pregnancy and foeto-placental development. Though much is known about initiation of cycling and associated risk factors, there are virtually no data on pregnancy rate per cycle for naturally mated cattle, especially for extensively managed, tropically adapted genotypes, which this study aimed to determine. Tropical composite (Bos indicus and African Sanga crosses with Bos taurus) and Brahman cattle (n = 2,181) of known pedigree in four-year groups at four sites were mated annually for 84 days. Body condition, ovarian function, pregnancies, calving and lactation were monitored through six full reproductive cycles using 4-8 weekly ultrasound of the reproductive tract outside the calving period and daily monitoring during calving. From this, dates of commencement of cycling and conception in each year were estimated for each animal, enabling calculation of established pregnancy for consecutive 21-day periods while cycling and of pregnancies within four months of calving while lactating (P4M). Pregnancy per 21-day period (cycle) during mating for cycling animals averaged 63%, 71%, 41% and 28% in four consecutive cycles. Pregnant per cycle was 2%-11% higher in tropical composites than in Brahmans. The only other consistently significant risk to becoming pregnant was if cycling commenced later than three weeks before mating commenced. P4M averaged 62% and was lower for cows in sub-optimal body condition and in first-parity and later-calving cows. Pregnant per cycle was moderately heritable (~20%), while heritability was moderate to high (33%) for P4M. Selection for pregnant per cycle could be achieved indirectly by selection for P4M, a trait that is readily measured.


Assuntos
Bovinos/fisiologia , Ciclo Estral , Taxa de Gravidez , Criação de Animais Domésticos/métodos , Animais , Cruzamento , Bovinos/genética , Copulação , Feminino , Lactação , Gravidez , Queensland , Fatores de Tempo , Clima Tropical
15.
J Dairy Res ; 88(3): 274-277, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34238391

RESUMO

The aim of this Research Communication was to apply the data mining technique to classify which environmental factors have the potential to motivate dairy cows to access natural shade. We defined two different areas at the silvopastoral system: shaded and sunny. Environmental factors and the frequency that dairy cows used each area were measured during four days, for 8 h each day. The shaded areas were the most used by dairy cows and presented the lowest mean values of all environmental factors. Solar radiation was the environmental factor with most potential to classify the dairy cow's decision to access shaded areas. Data mining is a machine learning technique with great potential to characterize the influence of the thermal environment in the cows' decision at the pasture.


Assuntos
Comportamento Animal/fisiologia , Bovinos/psicologia , Indústria de Laticínios/métodos , Meio Ambiente , Motivação/fisiologia , Luz Solar , Animais , Bovinos/fisiologia , Mineração de Dados , Feminino , Temperatura Alta
16.
Reprod Domest Anim ; 56(10): 1293-1301, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34288178

RESUMO

Conservation decisions based on neutral genetic diversity have been observed to promote retention of useful quantitative variation in biological populations. An experiment was undertaken to determine the association between microsatellite marker polymorphisms and phenotypic variation in semen production and cryosurvival traits in bulls. Thirty-five ejaculates were collected from ten bulls of two breeds and evaluated before and after cryopreservation for several semen traits. The bulls were also genotyped using a set of sixteen bovine-specific microsatellite marker loci. Fixation indices (FST ), heterozygosity and Nei's genetic distance measures were computed from allele frequency data for each of the bulls. Molecular and phenotypic data were used to compute tri-distance matrices for the ten bulls and correlated using Mantel's test in GenAIEx 6.5. The study revealed extensive heterogeneity in semen traits, heterozygosity and FST values among the bulls. Large pairwise phenotypic and genetic distances were also observed. Correlation between pairwise genetic distances and phenotypic distances was significant and highly positive for sperm viability (r = .61, p < .001) and moderately positive for sperm motility (r = .40-42, p < .05) variables. For sperm morphology, ejaculate volume and sperm concentration, correlation with genetic distances was positive, low and not significantly different from zero (p > .05). A tendency for a triangular-shaped relationship between genetic and phenotypic distances for post-thaw motility and viability traits was also observed. Accordingly, association with neutral genetic diversity was absent for semen production traits and moderate to highly positive for sperm cryosurvival traits. Given these findings, conservation decisions based on neutral genetic diversity may capture variation in some adaptive traits, but not others.


Assuntos
Bovinos/genética , Variação Genética , Sêmen/fisiologia , Espermatozoides/citologia , Animais , Bovinos/fisiologia , Criopreservação/veterinária , Masculino , Repetições de Microssatélites , Análise do Sêmen/veterinária , Preservação do Sêmen/veterinária , Motilidade Espermática/genética
17.
PLoS One ; 16(7): e0254410, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34292996

RESUMO

The aim of the current study was to investigate the relation between reticulorumen contractions and monitored cow behaviors. A purpose-built pressure measuring device was used and shown to be capable of detecting the known contraction patterns in the reticulorumen of four rumen-fistulated cows. Reticular pressure data was used to build a random forest algorithm, a learning algorithm based on a combination of decision trees, to detect rumination and other cow behaviors. In addition, we developed a peak-detection algorithm for rumination based on visual inspection of patterns in reticular pressure. Cow behaviors, differentiated in ruminating, eating, drinking, sleeping and 'other', as scored from video observation, were used to develop and test the algorithms. The results demonstrated that rumination of a cow can be detected by measuring pressure differences in the reticulum using either the random forest algorithm or the peak-detection algorithm. The random forest algorithm showed very robust performances for detecting rumination with an accuracy of 0.98, a sensitivity of 0.95 and a specificity of 0.99. The peak-detection algorithm could detect rumination robustly, with an accuracy of 0.92, a sensitivity of 0.97 and a specificity of 0.90. In addition, we provide proof of principle that a random forest algorithm can also detect eating, drinking and sleeping behavior from the same data with performances above 0.90 for all measures. The measurement device used in this study needed rumen-fistulated cows, but the results indicate that behavior detection using algorithms based on only measurements in the reticulum is feasible. This is promising as it may allow future wireless sensor techniques in the reticulum to continuously monitor a range of important behaviors of cows.


Assuntos
Algoritmos , Comportamento Animal/fisiologia , Bovinos/fisiologia , Pressão , Retículo/fisiologia , Animais , Feminino
18.
Sci Rep ; 11(1): 14839, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290309

RESUMO

Objective was to elucidate the effects of heat stress (HS) on embryo development during first 16 gestational days (GD) and circulating hormone concentrations on GD-16 in lactating Holstein cows. Cows in HS and control (CON) groups were exposed to temperature humidity index (THI) of ≥ 73 and < 73, respectively, for 3 weeks before the experiment. GD-7 (67 vs 49%) and GD-16 (52 vs. 31%) conception rates following single insemination were greater (P < 0.01) for CON compared with HS cows. Control cows produced more GD-7 transferrable embryos following superovulation compared with HS cows (84.8 vs 53.1%; P < 0.001). Mean (± SEM) length (45.2 ± 10.6 vs. 59.2 ± 9.1 mm) and weight (31.4 ± 4.3 vs. 42.4 ± 6.2 mg) of GD-16 conceptus were greater for CON compared with HS cows (P < 0.05). Control cows yielded more filamentous conceptus (≥ 25 mm) compared with HS cows (71 vs 45%; P < 0.05). Progesterone (2.09-fold) was higher, and cortisol (1.86-fold), prolactin (1.60-fold), substance-P (1.55-fold), Isoprostane-8 (1.34-fold) and prostaglandin F metabolites (1.97-fold) were lower in CON compared with HS cows (P < 0.05). Progesterone positively, and substance-P, isoprostane-8 and the THI negatively were associated with GD-16 conceptus length (P < 0.05). In conclusion, altered hormones concentrations in heat-stressed cows plausibly resulted in lower GD-7 and GD-16 conception rates, fewer GD-7 transferable embryos, and stunted GD-16 conceptus elongation.


Assuntos
Bovinos/embriologia , Bovinos/fisiologia , Desenvolvimento Embrionário/fisiologia , Resposta ao Choque Térmico/fisiologia , Gravidez/fisiologia , Animais , Bovinos/metabolismo , Feminino , Idade Gestacional , Hidrocortisona/metabolismo , Isoprostanos/metabolismo , Lactação , Progesterona/metabolismo , Prolactina/metabolismo , Prostaglandinas F/metabolismo , Substância P/metabolismo
19.
Reprod Domest Anim ; 56(10): 1279-1285, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34219301

RESUMO

This study aimed to evaluate the correlation of seminal plasma IGF-I and total proteins from peripubertal bulls with semen characteristics and onset of puberty. Sixteen dairy Gyr bulls were separated into early (n = 8) and regular (n = 8) groups, according to the onset of puberty. Semen was monthly collected by electroejaculation from 14 to 26 months of age, and the onset of puberty was retrospectively determined (17.0 ± 1.6 and 19.2 ± 1.5 months, to early and regular group, respectively). Five time points were evaluated (day -60, day -30, day 0, day 30 and day 60 days of puberty), being day 0 considered as beginning of puberty. Scrotal circumference and body weight were also assessed. Semen characteristics were evaluated, the seminal plasma was separated by centrifugation and total protein and IGF-I concentrations were determined. There was no difference between groups to concentration of the seminal plasma total proteins, but we found an interaction between group and age. Seminal plasma IGF-I concentrations were not different between early and regular groups; thus, the data were combined for analysis. Combined IGF-I concentrations were positively correlated with sperm motility and concentration, age, body weight and scrotal circumference. Negative correlation was found between IGF-I concentration and total sperm defects. Increased IGF-I was observed in day -30 and day 0 of puberty in early and regular groups, respectively. Seminal plasma total proteins are involved in peripubertal modifications and IGF-I from Zebus dairy bulls can influence the seminal characteristics and the growth factor increase occurs concomitantly with body growth but cannot be used to define puberty bulls earlier.


Assuntos
Bovinos/fisiologia , Fator de Crescimento Insulin-Like I/análise , Proteínas/análise , Sêmen/química , Animais , Peso Corporal , Masculino , Escroto/anatomia & histologia , Maturidade Sexual/fisiologia , Motilidade Espermática
20.
Sci Rep ; 11(1): 13642, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34211046

RESUMO

Bovine mastitis is one of the most important economic and health issues in dairy farms. Data collection during routine recording procedures and access to large datasets have shed the light on the possibility to use trained machine learning algorithms to predict the udder health status of cows. In this study, we compared eight different machine learning methods (Linear Discriminant Analysis, Generalized Linear Model with logit link function, Naïve Bayes, Classification and Regression Trees, k-Nearest Neighbors, Support Vector Machines, Random Forest and Neural Network) to predict udder health status of cows based on somatic cell counts. Prediction accuracies of all methods were above 75%. According to different metrics, Neural Network, Random Forest and linear methods had the best performance in predicting udder health classes at a given test-day (healthy or mastitic according to somatic cell count below or above a predefined threshold of 200,000 cells/mL) based on the cow's milk traits recorded at previous test-day. Our findings suggest machine learning algorithms as a promising tool to improve decision making for farmers. Machine learning analysis would improve the surveillance methods and help farmers to identify in advance those cows that would possibly have high somatic cell count in the subsequent test-day.


Assuntos
Bovinos , Indústria de Laticínios , Aprendizado de Máquina , Mastite Bovina/diagnóstico , Animais , Bovinos/fisiologia , Contagem de Células , Diagnóstico por Computador/veterinária , Feminino , Prognóstico
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