RESUMEN
The SLICK1 mutation in the prolactin receptor (PRLR) results in a short-hair coat and increased ability to regulate body temperature during heat stress. It is unclear whether the mutation affects capacity for sweating. The objective of this observational study was to evaluate whether the SLICK1 mutation in PRLR alters characteristics of skin related to sweat gland abundance or function. Skin biopsies from 31 Holstein heifers, including 14 wild-type (SL-/-) and 17 heterozygous slick (SL+/-), were subjected to histological analysis to determine the percent of the surface area of skin sections that are occupied by sweat glands. We detected no effect of genotype on this variable. Immunohistochemical analysis of the forkhead transcription factor A1 (FOXA1), a protein essential for sweating in mice, from 6 SL-/- and 6 SL+/- heifers indicated twice as much FOXA1 in sweat glandular epithelia of SL+/- heifers as in SL-/- heifers. Results from RNA sequencing of skin biopsies from 5 SL-/- and 7 SL+/- heifers revealed few genes that were differentially expressed and none that have been associated with sweat gland development or function. In conclusion, results do not support the idea that the SLICK1 mutation changes the abundance of sweat glands in skin, but do show that functional properties of sweat glands, as indicated by increased abundance of immunoreactive FOXA1, are modified by inheritance of the mutation in PRLR.
Asunto(s)
Receptores de Prolactina , Glándulas Sudoríparas , Animales , Bovinos , Femenino , Ratones , Factores de Transcripción Forkhead/genética , Expresión Génica , MutaciónRESUMEN
The slick-hair phenotype in cattle is due to one of a series of mutations in the prolactin receptor (PRLR) that cause truncation of the C-terminal region of the protein involved in JAK2/STAT5 activation during prolactin signaling. Here we evaluated whether the inheritance of the SLICK1 allele, the first slick mutation discovered, is inherited in a fashion consistent with Hardy-Weinberg equilibrium. It was hypothesized that any deleterious effect of inheriting the allele on embryonic or fetal function would result in reduced frequency of the allele in offspring. A total of 525 Holstein and Senepol cattle produced from matings involving one or both parents with the SLICK1 allele were genotyped. The observed frequency of the SLICK1 allele (0.247) was not significantly different than the expected frequency of 0.269. These results support the idea that inheritance of the SLICK1 allele does not act in the embryo or fetus to modify its competence to complete development to term.
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Bovinos/genética , Cabello/fisiología , Herencia , Fenotipo , Receptores de Prolactina/genética , Alelos , AnimalesRESUMEN
Thermal stress limits beef cattle production and a shorter hair coat is a key thermoregulative adaptation that allows cattle to lose heat more efficiently. The objective of this study was to identify genetic variants associated with the length of the undercoat and topcoat of cattle utilizing 1456 Brangus heifers genotyped with the Bovine GGP F250 array. Seven SNPs in the PCCA gene were significantly associated with undercoat length. PCCA belongs to the biotin transport and metabolism pathway. Biotin deficiency has been reported to cause hair loss. Four SNPs in an 110 kb including a missense mutation in the PRLR gene were significantly associated with topcoat length. Whereas the association of this polymorphism with hair length is novel, the SLICK mutation in PRLR has previously been demonstrated to significantly impact hair length in cattle. These newly detected genetic variants may contribute to a shorter hair coat and more thermotolerant animals.
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Bovinos/fisiología , Variación Genética/fisiología , Cabello/fisiología , Termotolerancia/genética , Animales , Bovinos/genética , Estudio de Asociación del Genoma Completo/veterinariaRESUMEN
Fertility-promoting effects of treatment of lactating dairy cattle with human chorionic gonadotropin (hCG) after artificial insemination (AI) have been variable. Here, we tested whether fertility response to hCG in lactating Holstein cows interacts with genotype and parity. Primiparous (n = 538) and multiparous (n = 613) cows were treated with hCG (3,300 IU) or vehicle 5 d after AI. Pregnancy was diagnosed on d 32 and 60 after AI. A subset of cows (n = 593-701) was genotyped for 4 single nucleotide polymorphisms (SNP) previously associated with fertility. Treatment with hCG increased progesterone concentration on d 12 after AI regardless of genotype or parity. Pregnancy per AI was improved by hCG in primiparous cows but not in multiparous cows. Moreover, hCG treatment interacted with a SNP in coenzyme Q9 (COQ9) to affect fertility. Fertility of cows treated with vehicle was greatest for the AA allele, whereas fertility was lowest for the same genotype among cows treated with hCG. Pregnancy per AI was also affected by genotype for heat shock protein A1-like (HSPA1L) and progesterone receptor (PGR), but no interactions were observed with treatment. Genotype for a SNP in prostate androgen-regulated mucin-like protein 1 (PARM1) was not associated with fertility. Overall, results show that variation in response to hCG treatment on fertility depends on parity and interacts with a SNP in COQ9.
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Bovinos/genética , Bovinos/fisiología , Gonadotropina Coriónica/administración & dosificación , Fertilidad/efectos de los fármacos , Lactancia/efectos de los fármacos , Animales , Bovinos/sangre , Femenino , Genotipo , Humanos , Inseminación Artificial/veterinaria , Paridad/efectos de los fármacos , Embarazo , Progesterona/sangre , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismoRESUMEN
Maternal heat stress during late gestation affects calf function during postnatal life. The objective of the present study was to evaluate whether calves that experience heat stress in utero have altered thermoregulatory responses to acute heat stress later in life. Specifically, the hypothesis was that heat stress in utero would improve the response to acute heat stress at maturity. Females were born to dams exposed to heat stress or cooled during late gestation preceding their birth. All animals were raised postnatally under identical management. Twelve lactating Holstein cows that were exposed to in utero heat stress (HT) and 12 that were exposed to in utero control (CON) were used. A heat stress challenge was conducted in 3 blocks using 4 HT and 4 CON cows matched according to milk yield, stage of lactation, and parity. Each challenge consisted of transfer from a barn with shade and evaporative cooling to one with shade but no additional cooling for 48 h. The challenge was replicated twice for each block. Sweating rate, respiration rate, rectal temperature (RT), and skin temperature were measured on each cow at 0900, 1100, 1300, 1500, and 1700 h for 2 consecutive days. Mean ambient temperature across 6 challenge days was 26.15 ± 4.75°C. Tendencies for differences at 1700 h were observed between treatments for RT (HT: 39.5 ± 0.1; CON: 39.6 ± 0.1°C; = 0.065), however, there was no difference in respiration rate (HT: 77.6 ± 1.6; CON: 79.5 ± 1.6 bpm; = 0.85). Sweating rate for shaved skin (HT: 29.4 ± 2.0; CON: 36.0 ± 2.0 g/mh; = 0.057) and for non-shaved skin (HT: 22.5 ± 1.5; CON: 29.2 ± 1.2 g/mh; = 0.01) differed between groups. However, there was no effect on skin temperature at the shaved location (HT: 36.2 ± 0.2; CON: 36.0 ± 0.2°C; = 0.81), but there was a tendency for differences for the non-shaved area (HT: 35.4 ± 0.2; CON: 34.9 ± 0.2°C; = 0.097). Cows that underwent in utero heat stress had greater skin temperature at 1700 h vs. in utero control cows, which may be because HT cows increased skin perfusion, and consequently greater cooling via conduction. In utero HT cows would then have higher heat loss and reduced core body temperature, which results in lower rectal temperature and lower sweating rate when exposed to heat stress. These results support the hypothesis that heat stress in utero in late gestation increases heat tolerance at maturity by increasing capacity to dissipate heat to maintain core body temperature.
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Bovinos/fisiología , Trastornos de Estrés por Calor/veterinaria , Leche/metabolismo , Estrés Fisiológico , Termotolerancia , Animales , Temperatura Corporal , Regulación de la Temperatura Corporal , Bovinos/embriología , Femenino , Trastornos de Estrés por Calor/fisiopatología , Trastornos de Estrés por Calor/prevención & control , Calor , Lactancia , Embarazo , Frecuencia Respiratoria , SudoraciónRESUMEN
Here we report a previously undescribed coat color phenotype in Holstein cattle. Larson Blue Holsteins, located on a dairy in south Florida, exhibit a coloration pattern that is similar to that of black and white or red and white Holsteins except that, instead of being black or red, darker regions of the body vary in color from gray to taupe. The Larson Blue phenotype was readily apparent in young calves. The phenotype is not due to inheritance of known mutations causing coat color variation in cattle, including dominant red, Telstar, silver color dilutor, or Dun color. Three variants with moderate effects on the () gene were identified in 2 Larson blue cows. Despite being lighter in color, there was no difference in daily variation in vaginal temperature between Larson Blue and other Holsteins when recorded during the summer for cows housed in free-stall barns with shade, fans, and sprinklers. Similarly, there was no effect of the Larson Blue phenotype on seasonal variation in milk yield. Therefore, the phenotype confers no advantage in terms of response to heat stress when cattle are housed in facilities with extensive cooling.
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Bovinos/fisiología , Cabello/fisiología , Calor , Lactancia/fisiología , Pigmentación/fisiología , Pigmentos Biológicos/metabolismo , Animales , Regulación de la Temperatura Corporal/genética , Bovinos/genética , Clima , Femenino , Florida , Trastornos de Estrés por Calor/veterinaria , Leche , Pigmentación/genética , Pigmentos Biológicos/genética , Estaciones del Año , TemperaturaRESUMEN
The objectives of this study were to estimate variance components and identify regions of the genome associated with traits related to embryo transfer in Holsteins. Reproductive technologies are used in the dairy industry to increase the reproductive rate of superior females. A drawback of these methods remains the variability of animal responses to the procedures. If some variability can be explained genetically, selection can be used to improve animal response. Data collected from a Holstein dairy farm in Florida from 2008 to 2015 included 926 superovulation records (number of structures recovered and number of good embryos), 628 in vitro fertilization records (number of oocytes collected, number of cleaved embryos, number of high- and low-quality embryos, and number of transferrable embryos), and 12,089 embryo transfer records (pregnancy success). Two methods of transformation (logarithmic and Anscombe) were applied to count variables and results were compared. Univariate animal models were fitted for each trait with the exception of pregnancy success after embryo transfer. Due to the binary nature of the latter trait, a threshold liability model was fitted that accounted for the genetic effect of both the recipient and the embryo. Both transformation methods produced similar results. Single-step genomic BLUP analyses were performed and SNP effects estimated for traits with a significant genetic component. Heritability of number of structures recovered and number of good embryos when log-transformed were 0.27 ± 0.08 and 0.15 ± 0.07, respectively. Heritability estimates from the in vitro fertilization data ranged from 0.01 ± 0.08 to 0.21 ± 0.15, but were not significantly different from zero. Recipient and embryo heritability (standard deviation) of pregnancy success after embryo transfer was 0.03 (0.01) and 0.02 (0.01), respectively. The 10-SNP window explaining the largest proportion of variance (0.37%) for total structures collected was located on chromosome 8 beginning at 55,663,248 bp. Similar regions were identified for number of good embryos, with the largest proportion of variance (0.43%) explained by a 10-SNP window on chromosome 14 beginning at 26,713,734 bp. Results indicate that there is a genetic component for some traits related to superovulation and that selection should be possible. Moreover, the genetic component for superovulation traits involves some genomic regions that are similar to those for other fertility traits currently evaluated.
Asunto(s)
Transferencia de Embrión/veterinaria , Superovulación , Animales , Bovinos , Femenino , Fertilización In Vitro/veterinaria , Oocitos , ReproducciónRESUMEN
PRIMARY OBJECTIVES: To establish and comprehensively evaluate a large cohort of US veterans who served in recent military conflicts in order to better understand possible chronic and late-life effects of mild traumatic brain injury (mTBI), including those that may stem from neurodegeneration. RESEARCH DESIGN: Cross-sectional and prospective longitudinal. METHODS AND PROCEDURES: Inclusion criteria are prior combat exposure and deployment(s) in Operation Enduring Freedom, Operation Iraqi Freedom or one of their follow-on conflicts (collectively OEF/OIF). Effects of mTBI will be assessed by enrolling participants across the entire spectrum of mTBI, from entirely negative to many mTBIs. Longitudinal assessments consist of in-person comprehensive testing at least every 5 years, with interval annual telephonic testing. The primary outcome is the composite score on the NIH Toolbox neuropsychological test battery. Assessments also include structured interviews, questionnaires, traditional neuropsychological testing, motor, sensory and vestibular functions, neuroimaging, electrophysiology, genotypes and biomarkers. MAIN OUTCOMES AND RESULTS: The authors fully describe the study methods and measures and report demographic and exposure characteristics from the early portion of the cohort of OEF/OIF veterans. CONCLUSIONS: This centrepiece observational study of the Chronic Effects of Neurotrauma Consortium (CENC) is successfully launched and, within several years, should provide fertile data to begin investigating its aims.
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Conmoción Encefálica/complicaciones , Conmoción Encefálica/epidemiología , Trastornos del Conocimiento/etiología , Trastornos de la Motilidad Ocular/etiología , Adulto , Campaña Afgana 2001- , Conmoción Encefálica/diagnóstico , Estudios de Cohortes , Estudios Transversales , Electroencefalografía , Femenino , Humanos , Guerra de Irak 2003-2011 , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Autoinforme , Estados Unidos , Veteranos , Adulto JovenRESUMEN
OBJECTIVE: Evaluate sleep quality, its correlates, and the effect of telephone-based problem-solving treatment (PST) in active duty postdeployment service members with mild traumatic brain injury (mTBI) SETTING:: Randomized clinical trial. PARTICIPANTS: Active duty service members with combat-related mTBI. STUDY DESIGN: Education-only (EO) and PST groups (N = 178 each) received printed study materials and 12 educational brochures. The PST group additionally received up to 12 PST telephone calls addressing participant-selected issues. Outcomes were evaluated postintervention (6 months) and at 12 months. MAIN MEASURE: Pittsburgh Sleep Quality Index. RESULTS: Sleep quality was manifestly poor in both groups at baseline (Pittsburgh Sleep Quality Index = 12.5 ± 4). Overall sleep quality was significantly different between the PST and EO groups at 6 months (P = .003) but not at 12 months. Longitudinally, PST significantly improved sleep quality at 6 months (P = .001) but not over the follow-up. Low sleep quality was associated with concussion symptoms, pain, depression, and posttraumatic stress disorder at all time points (P < .0001). CONCLUSIONS: Sleep disorders, common in postdeployment service members with mTBI, are strongly associated with the presence of pain, posttraumatic stress disorder, and depression. Telephone-based PST may be an effective therapeutic approach for reducing sleep disorders in this population. Research should focus on maintenance of treatment gains.
Asunto(s)
Conmoción Encefálica/psicología , Conmoción Encefálica/rehabilitación , Personal Militar , Solución de Problemas , Trastornos del Sueño-Vigilia/terapia , Telemedicina , Adulto , Conmoción Encefálica/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos del Sueño-Vigilia/etiología , Trastornos por Estrés Postraumático/etiología , Trastornos por Estrés Postraumático/terapia , Teléfono , Adulto JovenRESUMEN
Dairy cows with increased rectal temperature experience lower milk yield and fertility. Rectal temperature during heat stress is heritable, so genetic selection for body temperature regulation could reduce effects of heat stress on production. One aim of the study was to validate the relationship between genotype and heat tolerance for single nucleotide polymorphisms (SNPs) previously associated with resistance to heat stress. A second aim was to identify new SNPs associated with heat stress resistance. Thermotolerance was assessed in lactating Holsteins during the summer by measuring rectal temperature (a direct measurement of body temperature regulation; n = 435), respiration rate (an indirect measurement of body temperature regulation, n = 450) and sweating rate (the major evaporative cooling mechanism in cattle, n = 455). The association between genotype and thermotolerance was evaluated for 19 SNPs previously associated with rectal temperature from a genomewide analysis study (GWAS), four SNPs previously associated with change in milk yield during heat stress from GWAS, 2 candidate gene SNPs previously associated with rectal temperature and respiration rate during heat stress (ATPA1A and HSP70A) and 66 SNPs in genes previously shown to be associated with reproduction, production or health traits in Holsteins. For SNPs previously associated with heat tolerance, regions of BTA4, BTA6 and BTA24 were associated with rectal temperature; regions of BTA6 and BTA24 were associated with respiration rate; and regions of BTA5, BTA26 and BTA29 were associated with sweating rate. New SNPs were identified for rectal temperature (n = 12), respiration rate (n = 8) and sweating rate (n = 3) from among those previously associated with production, reproduction or health traits. The SNP that explained the most variation were PGR and ASL for rectal temperature, ACAT2 and HSD17B7 for respiration rate, and ARL6IP1 and SERPINE2 for sweating rate. ARL6IP1 was associated with all three thermotolerance traits. In conclusion, specific genetic markers responsible for genetic variation in thermoregulation during heat stress in Holsteins were identified. These markers may prove useful in genetic selection for heat tolerance in Holstein cattle.
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Regulación de la Temperatura Corporal/genética , Bovinos/genética , Respuesta al Choque Térmico/genética , Lactancia/metabolismo , Polimorfismo de Nucleótido Simple , Animales , Bovinos/metabolismo , Femenino , Fertilidad , Marcadores Genéticos , Estudio de Asociación del Genoma Completo , Genotipo , Calor , Recto/fisiología , Reproducción , SudoraciónRESUMEN
The SLICK haplotype (http://omia.angis.org.au/OMIA001372/9913/) in cattle confers animals with a short and sleek hair coat. Originally identified in Senepol cattle, the gene has been introduced into Holsteins. The objectives of the current study were to determine (1) whether lactating Holsteins with the slick hair phenotype have superior ability for thermoregulation compared with wild-type cows or relatives not inheriting the SLICK haplotype, and (2) whether seasonal depression in milk yield would be reduced in SLICK cows. In experiment 1, diurnal variation in vaginal temperature in the summer was monitored for cows housed in a freestall barn with fans and sprinklers. Vaginal temperatures were lower in slick-haired cows than in relatives and wild-type cows. In experiment 2, acute responses to heat stress were monitored after cows were moved to a dry lot in which the only heat abatement was shade cloth. The increases in rectal temperature and respiration rate caused by heat stress during the day were lower for slick cows than for relatives or wild-type cows. Moreover, sweating rate was higher for slick cows than for cows of the other 2 types. In experiment 3, effects of season of calving (summer vs. winter) on milk yield and composition were determined. Compared with milk yield of cows calving in winter, milk yield during the first 90 d in milk was lower for cows calving in the summer. However, this reduction was less pronounced for slick cows than for wild-type cows. In conclusion, Holsteins with slick hair have superior thermoregulatory ability compared with non-slick animals and experience a less drastic depression in milk yield during the summer.
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Regulación de la Temperatura Corporal/genética , Bovinos/genética , Trastornos de Estrés por Calor/genética , Trastornos de Estrés por Calor/veterinaria , Lactancia , Animales , Femenino , Sitios Genéticos , Técnicas de Genotipaje , Cabello , Haplotipos , Calor , Vivienda para Animales , Modelos Lineales , Leche , Polimorfismo de Nucleótido Simple , Frecuencia Respiratoria , Estaciones del AñoRESUMEN
Genetic selection for body temperature during heat stress might be a useful approach to reduce the magnitude of heat stress effects on production and reproduction. Objectives of the study were to estimate the genetic parameters of rectal temperature (RT) in dairy cows in freestall barns under heat stress conditions and to determine the genetic and phenotypic correlations of rectal temperature with other traits. Afternoon RT were measured in a total of 1,695 lactating Holstein cows sired by 509 bulls during the summer in North Florida. Genetic parameters were estimated with Gibbs sampling, and best linear unbiased predictions of breeding values were predicted using an animal model. The heritability of RT was estimated to be 0.17 ± 0.13. Predicted transmitting abilities for rectal temperature changed 0.0068 ± 0.0020°C/yr from (birth year) 2002 to 2008. Approximate genetic correlations between RT and 305-d milk, fat, and protein yields, productive life, and net merit were significant and positive, whereas approximate genetic correlations between RT and somatic cell count score and daughter pregnancy rate were significant and negative. Rectal temperature during heat stress has moderate heritability, but genetic correlations with economically important traits mean that selection for RT could lead to lower productivity unless methods are used to identify genes affecting RT that do not adversely affect other traits of economic importance.
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Temperatura Corporal/genética , Bovinos/genética , Lactancia/genética , Carácter Cuantitativo Heredable , Reproducción/genética , Animales , Femenino , Genotipo , Leche/química , Leche/normas , Linaje , Fenotipo , Embarazo , RectoRESUMEN
The objectives of this experiment were to evaluate the accuracy of ultrasonography to measure subcutaneous fat thickness (SFT) and LM traits (area, depth, and width) in live Awassi lambs of different sexes, predict actual SFT and LM traits without damage to the carcass, and improve carcass classification. Data were obtained from ultrasound scans of 20 female and 10 male lambs. Female lambs were randomly divided into light (FL; n = 10) and heavy (FH; n = 10) finishing groups. Slaughter weights of lambs in FL were 30 kg and for FH and male groups were 40 kg. Subcutaneous fat thickness and LM traits, cross-sectional area between the 12th and 13th rib were measured using real-time ultrasound in vivo and on the carcass after slaughter. All ultrasound and carcass measurements were different (P > 0.05) except carcass yield and carcass LM width in female lambs (FL and FH). Between different sex groups, all ultrasound and carcass measurements were the same except ultrasound SFT (USFT; P = 0.04) and carcass SFT (CSFT; P = 0.03). Significant correlation coefficients were between USFT and CSFT (0.93, P < 0.01; 0.76, P = 0.02), ultrasound LM depth (ULMD) and carcass LM depth (CLMD; 0.64, P = 0.05; 0.77, P < 0.01), and ultrasound LM area (ULMA) and carcass LM area (CLMA; 0.88, 0.84; P < 0.01) for female lambs in FL and FH groups. Also, similar correlations were determined significantly between USFT and CSFT (0.84, P < 0.01; 0.76, P = 0.02), ULMD and CLMD (0.69, P = 0.03; 0.77, P < 0.01), and ULMA and CLMA (0.88, 0.84; P < 0.01) for male lambs in male and FH groups. The introduction of USFT and ULMA as independent variables in addition to BW in the multiple regression equations further improved the variations for CSFT (88, 75, and 81%) and CLMA (78, 90, and 80%) for lambs in FL, FH, and male groups, respectively, whereas no improvement was observed for cold carcass weight with the exception of the FH group and carcass yield. These results indicate that in vivo USFT and ULMA in association with BW could be used to estimate CSFT, CLMA, and cold carcass weight ultrasound findings about LM, and SFT can be included to the selection programs for different BW and sex of Awassi lambs.
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Carne/normas , Ovinos/anatomía & histología , Ultrasonografía/veterinaria , Tejido Adiposo/diagnóstico por imagen , Animales , Peso Corporal , Femenino , Masculino , Músculo Esquelético/diagnóstico por imagen , Factores Sexuales , Grasa Subcutánea/diagnóstico por imagenRESUMEN
We compared diurnal patterns of vaginal temperature in lactating cows under grazing conditions to evaluate genotype effects on body temperature regulation. Genotypes evaluated were Holstein, Jersey, Jersey x Holstein and Swedish Red x Holstein. The comparison of Holstein and Jersey versus Jersey x Holstein provided a test of whether heterosis effects body temperature regulation. Cows were fitted with intravaginal temperature recording devices that measured vaginal temperature every 15 min for 7 days. Vaginal temperature was affected by time of day (P < 0.0001) and genotype x time (P < 0.0001) regardless of whether days in milk and milk yield were used as covariates. Additional analyses indicated that the Swedish Red x Holstein had a different pattern of vaginal temperatures than the other three genotypes (Swedish Red x Holstein vs others x time; P < 0.0001) and that Holstein and Jersey had a different pattern than Jersey x Holstein [(Holstein + Jersey vs Jersey x Holstein) x time, P < 0.0001]. However, Holstein had a similar pattern to Jersey [(Holstein vs Jersey) x time, P > 0.10]. These genotype x time interactions reflect two effects. First, Swedish Red x Holstein had higher vaginal temperatures than the other genotypes in the late morning and afternoon but not after the evening milking. Secondly, Jersey x Holstein had lower vaginal temperatures than other genotypes in the late morning and afternoon and again in the late night and early morning. Results point out that there are effects of specific genotypes and evidence for heterosis on regulation of body temperature of lactating cows maintained under grazing conditions and suggest that genetic improvement for thermotolerance through breed choice or genetic selection is possible.
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Aclimatación/fisiología , Temperatura Corporal/fisiología , Bovinos/clasificación , Bovinos/fisiología , Clima , Conducta Alimentaria/fisiología , Vigor Híbrido/fisiología , Animales , Florida , Calor , Lactancia/fisiología , Especificidad de la EspecieRESUMEN
Several temperature-humidity indexes (THI) have been used to estimate the degree of thermal stress experienced by dairy cows. The present objectives were to develop equations using meteorological variables that predicted rectal temperature of lactating cows in a subtropical environment and compare the goodness of fit of these equations to those using 8 different THI. Rectal temperature was measured between 1500 and 1700 h in 1,280 lactating Holstein cows in north central Florida between August and December. Meteorological data recorded in the barn where cows were located included dry bulb temperature (T(db)), relative humidity (RH), dew point temperature, and wind speed. Wet bulb temperature was calculated. In the first series of analyses, regression analysis was used to model rectal temperature using the meteorological variables as well as THI. The r(2) using T(db) (0.41) was slightly less than for models using all but one THI (r(2) between 0.42 and 0.43). The r(2) for equations using T(db) could be improved by adding RH (r(2) = 0.43) or RH and RH(2) (r(2) = 0.44) to the model. In the second analysis, regression analysis was performed using forward selection, backward elimination, and stepwise selection procedures with the meteorological variables. All models gave a similar goodness of fit (r(2) = 0.44). An analysis of variance with rectal temperature as a class variable was performed to determine the least squares means of meteorological measurements associated with hyperthermia. A T(db) of 29.7 degrees C was associated with rectal temperature of 39 degrees C, and a T(db) of 31.4 degrees C was associated with rectal temperature of 39.5 degrees C. In conclusion, T(db) is nearly as good a predictor of rectal temperatures of lactating Holsteins in a subtropical environment as THI. Estimates of values of meteorological variables associated with specific rectal temperatures should prove valuable in relating environmental conditions to the magnitude of hyperthermia experienced by heat-stressed cows.
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Ambiente , Calor , Humedad , Lactancia , Estrés Fisiológico/fisiología , Animales , Bovinos , Industria Lechera , Femenino , Análisis de los Mínimos Cuadrados , Modelos BiológicosRESUMEN
This experiment was conducted to investigate the effect of cafeteria (CF) and conventional (CN) feeding systems on feed intake, feed preferences with respect to voluntary feed source intake, feed conversion rate (FCR) and fattening performance of native Awassi lambs. Sixteen, 3 month old male lambs were used and kept individually for 70 days. Lambs in CF (n = 8) were offered to consume the main ingredients of barley, soybean meal (SBM), sunflower seed meal (SFM) and alfalfa straw, separately, while lambs in CN (n = 8) were fed with a concentrate feed containing 11.34 MJ/kg ME, 17.53% crude protein with the mixture of the same feed sources and alfalfa straw. The initial and final live weights of lambs were similar among groups (P > 0.05). Daily voluntary intake of ash, fat and neutral detergent fiber (NDF) consumptions among groups were quite different during the experiment (P < 0.001). Neither biweekly nor total results of voluntary protein intake between groups were not found statistically significant (P > 0.05). From beginning to the end of the study, the proportional barley intake increased 34 to 43% but reduced for SBM intake from 37 to 23% for the lambs in CF. On the other hand, the SFM intake of lambs did not changed significantly during the experiment and ranged between 2-5%. Lambs in CF did not consume SFM to meet their protein requirement and had 12.5% better total FCR result than the lambs in CN (6.86 and 7.84, respectively) (P > 0.05). The difference of average DWG, total live weight gain, final live weight of lambs in groups were similar (P > 0.05). In conclusion, Awassi lambs in CF can select a diet matching their nutritional requirements from a group of feed sources in response to their growth period when compared to CN system and better FCR result might help to decrease the feed expenses for fattening of native Awassi lambs.
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Alimentación Animal/análisis , Dieta/veterinaria , Preferencias Alimentarias , Ovinos/crecimiento & desarrollo , Aumento de Peso , Crianza de Animales Domésticos , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , TurquíaRESUMEN
Animals inheriting the slick hair gene have a short, sleek, and sometimes glossy coat. The objective of the present study was to determine whether slick-haired Holstein cows regulate body temperature more effectively than wild-type Holstein cows when exposed to an acute increase in heat stress. Lactating slick cows (n = 10) and wild-type cows (n = 10) were placed for 10 h in an indoor environment with a solid roof, fans, and evaporative cooling or in an outdoor environment with shade cloth and no fans or evaporative cooling. Cows were exposed to both environments in a single reversal design. Vaginal temperature, respiration rate, surface temperature, and sweating rate were measured at 1200, 1500, 1800, and 2100 h (replicate 1) or 1200 and 1500 h (replicate 2), and blood samples were collected for plasma cortisol concentration. Cows in the outdoor environment had higher vaginal and surface temperatures, respiration rates, and sweating rates than cows in the indoor environment. In both environments, slick-haired cows had lower vaginal temperatures (indoor: 39.0 vs. 39.4 degrees C; outdoor 39.6 vs. 40.2 degrees C; SEM = 0.07) and respiration rate (indoor: 67 vs. 79 breaths/ min; outdoor 97 vs. 107 breaths/min; SEM = 5.5) than wild-type cows and greater sweating rates in unclipped areas of skin (indoor: 57 vs. 43 g x h(-1)/m(2); outdoor 82 vs. 61 g x h(-1)/m(2); SEM = 8). Clipping the hair at the site of sweating measurement eliminated the difference between slick-haired and wild-type cows. Results indicate that slick-haired Holstein cows can regulate body temperature more effectively than wild-type cows during heat stress. One reason slick-haired animals are better able to regulate body temperature is increased sweating rate.
Asunto(s)
Regulación de la Temperatura Corporal/fisiología , Bovinos/fisiología , Cabello/fisiología , Calor , Lactancia/fisiología , Animales , Temperatura Corporal/fisiología , Ambiente , Femenino , Hidrocortisona/sangre , Distribución Aleatoria , Respiración , Sudoración/fisiología , Factores de TiempoRESUMEN
BACKGROUND: Mild traumatic brain injury (MTBI) is a significant public health problem affecting approximately 1 million people annually in the USA. A total of 10-15% of individuals are estimated to have persistent post-traumatic symptoms. This study aimed to determine whether focused, scheduled telephone counselling during the first 3 months after MTBI decreases symptoms and improves functioning at 6 months. METHODS: This was a two-group, parallel, randomised clinical trial with the outcome assessed by blinded examiner at 6 months after injury. 366 of 389 eligible subjects aged 16 years or older with MTBI were enrolled in the emergency department, with an 85% follow-up completion rate. Five telephone calls were completed, individualised for patient concerns and scripted to address education, reassurance and reactivation. Two composites were analysed, one relating to post-traumatic symptoms that developed or worsened after injury and their impact on functioning, the other related to general health status. RESULTS: The telephone counselling group had a significantly better outcome for symptoms (6.6 difference in adjusted mean symptom score, 95% confidence interval (CI) 1.2 to 12.0), but no difference in general health outcome (1.5 difference in adjusted mean functional score, 95% CI 2.2 to 5.2). A smaller proportion of the treatment group had each individual symptom (except anxiety) at assessment. Similarly, fewer of the treatment group had daily functioning negatively impacted by symptoms with the largest differences in work, leisure activities, memory and concentration and financial independence. CONCLUSIONS: Telephone counselling, focusing on symptom management, was successful in reducing chronic symptoms after MTBI. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, #NCT00483444.
Asunto(s)
Lesiones Encefálicas/psicología , Consejo , Líneas Directas , Trastornos por Estrés Postraumático , Adulto , Lesiones Encefálicas/diagnóstico por imagen , Demografía , Femenino , Escala de Coma de Glasgow , Humanos , Masculino , Índice de Severidad de la Enfermedad , Trastornos por Estrés Postraumático/etiología , Trastornos por Estrés Postraumático/prevención & control , Trastornos por Estrés Postraumático/psicología , Tomografía Computarizada por Rayos XRESUMEN
This study was carried out to establish the body weight, survival rate and some body measurements in German Shepherd puppies during the suckling period. The puppies were each weighed every seven days, and measured at ten different body sites every fourteen the day until weaning. The mean live weight of each puppy was measured as 776 g in the 1st week, 1750 g in the 4th week and 2614 g in the 8th week. The survival rate for the puppies was calculated at 95.2% and 83%, respectively at the end of the 4th and 8th week. Some of the body measurements of the puppies at the age when they were removed from suckling (52nd day) such as head length, head girth, body length, shoulder height, ear length, chest girth, rump height, front wrist girth, tail length and back wrist girth were found to be 14.76, 24.03, 22.97, 25.16, 5.93, 30.64, 24.16, 6.62, 15.51 and 5.99 cm, respectively.