RESUMO
This retrospective observational study aimed to assess the effect of temperature-humidity index (THI) at calving and in the last trimester of pregnancy and calve-related factors affecting passive transfer of maternal immunoglobulin using Brix refractometry in Holstein calves. Blood samples from 4411 Holstein calves from a single large dairy farm in spring 2022 were used. A subset of data containing 6318 calvings was used to determine the effect of climatic conditions on the occurrence of agammaglobulinemia. Risk factors predictive of failure of passive transfer (FPT) were calculated using multiple logistic models. Females were 1.4 times more likely not to have FPT (56%; Brix% > 8 equivalent to ≥ 10 g/L IgG) than males (47.2%). Calves born as singles increased the likelihood of not presenting FPT (52.6%) than calves born as twins (42.9%). Calves from cows with no dystocic delivery had a lower risk for FPT (odds ratio = 2.3) than calves from cows with dystocia. Agammaglobulinemia was 1.5 and 1.8 times more likely to occur in calves with THI ≥ 80 and ≥ 82 in the last trimester of gestation and at calving, respectively, than in calves not experiencing heat stress. Agammaglobulinemia was twice as likely to occur in male than in female calves. Calves with birth weight ≥ 37 kg and gestation length ≥ 275 kg were less likely to present agammaglobulinemia than lighter calves and calves with shorter gestation periods. This study raises questions for management practices in Holstein calves undergoing in utero heat stress and around calving to avoid agammaglobulinemia.
Assuntos
Agamaglobulinemia , Doenças dos Bovinos , Distocia , Animais , Bovinos , Feminino , Masculino , Gravidez , Agamaglobulinemia/veterinária , Anticorpos , Peso ao Nascer , Distocia/veterinária , Fatores de Risco , Estudos RetrospectivosRESUMO
The aim of this study was to determine effects of parity (primiparous vs. multiparous), seasonal heat stress at calving (summer vs. winter), and time postpartum on some parameters associated with colostrum quality in Holstein cows reared in the Sonoran Desert ecosystem. Forty-seven cows (11 primiparous and 36 multiparous) expected to calve during summer, and 46 cows during winter (14 primiparous and 32 multiparous) were randomly selected. Management and feeding before and after parturition were similar for cows in both seasons. After parturition, colostrum from all cows was evaluated for volume, weight, temperature, density, and content of fat, protein, solids non-fat (SNF), and immunoglobulins (IGG). Data were analyzed with a model that included effects of parity status, calving season, and time postpartum, as well as all interactions. Colostrum produced in summer was warmer (P < 0.01) by almost 6 °C than winter colostrum, while colostrum from multiparous was warmer (P = 0.02) by 1.2 °C than that produced by primiparous cows. Colostrum volume and weight were not impacted by parity, calving season or time postpartum. Density, protein, and SNF content in colostrum were higher (P < 0.01) in multiparous vs. primiparous cows, as well as at parturition (0 h postpartum) than at 12 h postpartum (P < 0.01). At calving (0 h), spring colostrum had higher fat content (P < 0.01) and lower (P < 0.01) IGG concentration than that collected in summer, and no difference (P > 0.05) between seasons was observed for these components at 12 h postpartum. Multiparous cows produced colostrum with higher (P < 0.01) IGG concentrations than primiparous cows. In conclusion, only 0-h colostrum and that from multiparous cows was categorized as "Excellent," meanwhile the colostrum produced under summer heat stress was characterized as "Good" with reduced fat content. While the lacteal secretion collected at 12 post-partum still classified as colostrum, substantially lower contents of IGG, protein, fat, and SNF decreased its classification to "Poor" from the classification of "Excellent" at 0 h postpartum.
Assuntos
Colostro , Lactação , Gravidez , Feminino , Humanos , Bovinos , Animais , Estações do Ano , Leite , Ecossistema , Período Pós-Parto , Imunoglobulina GRESUMO
This study aimed to describe the shedding pattern of gastrointestinal parasite eggs by a wild population of desert bighorn sheep (DBS; Ovis canadensis) in northern Mexico. Seventy-five fresh faecal samples were collected from the ground in each season within an hour after being expelled by these animals. The generalized linear mixed model showed that eggs per gram of faeces were highest in winter (577 ± 399) and lowest in summer (260 ± 198). Generalized linear models revealed that Strongyloides spp. predominated during most seasons with a peak in summer (85% of faecal samples analysed) and the absence of this helminth in winter. Nematodirus spp. was another helminth present in three seasons, with the presence of this nematode in 35% of the faecal samples in spring and 0% in summer. Other parasites in DBS faeces included Bunostomun spp., Trichostrongylus spp., Cooperia spp., Mecistocirrus digitatus, Haemonchus contortus, Chabertia ovina and Eimeria ovinoidalis. There were differences among seasons in the percentage of these helminths and coccidia in faecal samples for all these parasites. It was concluded that helminths egg output in DBS in a semi-arid rangeland is lowest in summer and spring and highest in autumn and winter. Furthermore, it was shown that DBS in the study site do not suffer from severe parasite burden. Therefore, this nematode parasite burden is compatible with the conservation and well-being of this particular population.
Assuntos
Helmintos , Enteropatias Parasitárias , Nematoides , Infecções por Nematoides , Parasitos , Doenças dos Ovinos , Carneiro da Montanha , Animais , Fezes/parasitologia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/veterinária , México/epidemiologia , Infecções por Nematoides/parasitologia , Contagem de Ovos de Parasitas , Prevalência , Estações do Ano , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/parasitologiaRESUMO
OBJETIVO Comparar los resultados clínicos, funcionales e imagenológicos de dos técnicas quirúrgicas para el manejo de fracturas conminutas de patela: con y sin eversión patelar. MÉTODOS En una serie de casos retrospectivos de fracturas conminutas de patela tratadas en el mismo centro entre 2014 y 2017, con un seguimiento ≥ 3 meses, se hizo una comparación entre el grupo con eversión y el grupo sin eversión. Los criterios de exclusión fueron patelectomía parcial o total, reinserción tendínea, o rehabilitación incompleta. Las variables analizadas fueron edad, sexo, tabaquismo, diabetes mellitus, energía del accidente, tipo de fractura, variables quirúrgicas (banda de tensión, tornillos, alambres, nudos, cerclaje circular), rango de movimiento (RDM) articular postoperatorio, presencia de osteosíntesis sintomática, puntaje de escalas funcionales (de Tegner-Lysholm y de Kujala) al alta definitiva, complicaciones (rigidez articular, infección, trombosis venosa profunda), y variables imagenológicos con tomografías computarizadas pre- y postoperatorias (brecha, desnivel articular > 2 mm, elementos de fijación intraarticular). RESULTADOS En total, 20 de 22 pacientes, 13 con eversión y 7 sin eversión, cumplieron con los criterios de selección. El seguimiento fue de 3 a 12 meses, y no hubo diferencias estadísticamente significativas respecto a las variables demográficas entre ambos grupos, lo cual los hace comparables. Destacaron el tiempo desde el ingreso al alta, con 7 meses para los pacientes con eversión y 5 meses para los sin eversión (p = 0.032), la proporción de pacientes con desnivel articular > 2 mm, con 7.7% para los con eversión y 14.3% para los sin eversión (p = 0.016), y una tendencia a resultados superiores en escalas funcionales para el grupo con eversión. CONCLUSIÓN El tratamiento de fracturas conminutas de patela con eversión parece ser una alternativa viable dados sus resultados imagenológicos y funcionales superiores a los de la técnica habitual.
PURPOSE To compare the clinical, functional and imaging outcomes of two surgical techniques for the treatment of comminuted patellar fractures: with and without eversion. METHODS In a retrospective series of cases of comminuted patellar fractures treated at a single center between 2014 and 2017, with a follow-up 3 months , we performed a comparison between the eversion group and the non-eversion group. The exclusion criteria were partial or total patellectomy, tendon reinsertion, or incomplete rehabilitation. The variables analyzed were age, gender, smoking, diabetes mellitus, the energy of the accident, the fracture type, surgical variables (tension band, screws, wires, knots, circular cerclage), postoperative joint range of motion (ROM), presence of symptomatic osteosynthesis, the scores on the functional scales (of Tegner-Lysholm and of Kujala) at the final discharge, complications (joint stiffness, infection, deep vein thrombosis), and pre- and postoperative computed tomography imaging variables (gap, step-off > 2mm, intra-articular fixation elements). RESULTS In total, 20 out of 22 patients, 13 undegoing eversion and 7 not undergoing eversion, met the selection criteria.. The follow-up ranged from 3 to 12 months, and there were no statistically significant differences regarding the demographic variables between both groups, which makes them comparable. The most remarkable results were the time from admission to final discharge, of 7 months for the patients in the eversion group, and of 5 months for those in the non-eversion group (p » 0.032), the proportion of patients with a step-off > 2 mm, with 7.7% for the eversion group and 14.3% for the non-eversion group (p » 0.016), and a tendency towards higher scores in the functional scales for the eversion group. CONCLUSION The treatment of comminuted patellar fractures with eversion seems to be a viable alternative, given its superior imaging and functional results compared to those of the usual technique.
Assuntos
Humanos , Patela/cirurgia , Fraturas Cominutivas/cirurgia , Patela/diagnóstico por imagem , Radiografia/métodos , Resultado do Tratamento , Fraturas Cominutivas/diagnóstico por imagem , Procedimentos OrtopédicosRESUMO
This study aimed to determine whether cows detected as tuberculosis (bTB) reactors and seropositive to brucellosis (bBR), as well as co-positive to bBR and bTB (bBR-bTB) and with a complete lactation before slaughter, were associated with reduced milk production and fertility. A total of 8068 productive and reproductive records of high-yielding Holstein cows from a single large dairy herd with a high prevalence of bTB and bBR were collected from 2012 to 2015. Lactation derived either from calving (n = 6019) or hormonally induced lactation (n = 2049), and all cows received growth hormone throughout lactation. For cows not induced into lactation, pregnancy rate to first service for healthy cows (C; 26.6%) was higher (P < 0.01) than bBR (15.2%), bTB (15.8%), and bBR-bTB (1.3%) cows. For induced cows, pregnancy rate to first service did not differ significantly among C, bBR, and bTB (14.5-17.3%) cows, but the percentage success of first service was extremely low (1.3%; P < 0.01) in bBR-bTB cows. Services per pregnancy (only pregnant cows) were lowest for C (3.3 ± 2.9; P < 0.01) and highest (6.4 ± 3.4) for bBR-bTB non-induced cows. This variable was lowest for C (2.9 ± 2.5; P < 0.01) and highest for bBR-bTB non-induced cows (6.3 ± 3.1). Pregnancy rate to all services did not differed for C (79.5%), bBR (76.7%), and bTB (75.9%) but was lower (58.9%; P < 0.01) for bBR-bTB non-induced cows. For induced cows this variable was highest for bBR (53.3%) and lowest for bBR-bTB (34.1%; P < 0.01) non-induced cows. 305-d milk production was increased by 4%, and total milk yield by 7% in TB-positive cows compared to that of the negative cows non-induced hormonally into lactation. This study showed the negative impact of the co-positivity for bTB and bBR on the reproductive efficiency of Holstein cows, although positive bTB and bBR tests enhanced milk yield.
Assuntos
Brucelose Bovina/diagnóstico , Doenças dos Bovinos , Fertilidade , Leite , Tuberculose Bovina/diagnóstico , Animais , Bovinos , Doenças dos Bovinos/diagnóstico , Feminino , Lactação , GravidezRESUMO
A total of 1338 high-yielding cows with five lactations from a large well-managed commercial dairy operation in a hot environment of northern Mexico were used to evaluate milk yield and reproductive performance of cows undergoing unplanned extended lactations (EL; > 450 days). The null hypothesis that cumulative milk yield during five consecutive lactations is the same in cows not having unplanned EL and cows with several EL was tested. All EL resulted from cows failing to become pregnant with ≥ 4 services. Cows were allocated to 1 of 6 groups according to the number of EL (EL0 for cows with no EL to EL5 for cows with 5 EL). Cumulative milk yield was highest (P < 0.01) for EL5 cows (95,499 kg) and lowest for EL0 cows (56,236 kg). Likewise, cumulative days in milk were greatest (P < 0.01) in EL5 (2968 days) and lowest in EL0 (1857 days) cows. Mean milk yield per lactation increased linearly with the increase in the number of extended lactations with a maximum of 19,099 kg of milk/lactation for EL5 cows. Mean daily milk yield/productive life was lowest (P < 0.01) for EL0 (30.2 kg) and highest for EL5 (32.1 kg). The percentage of days in milk relative to days from birth to the end of the fifth lactation was highest for EL5 (78.1%) and lowest for EL0 (59.6%), with EL2 to EL4 cows intermediate. Length of calving interval was longest (P < 0.01) for EL5 (24.7 months) and shortest for EL0 (15.5 months) cows. It was concluded that it is worthwhile maintaining high-yielding cows incapable to conceive before 230 days in milk because they did conceive again and produced considerable amounts of milk during their productive life, which substantially prolonged their permanence time in the herd.
Assuntos
Lactação , Leite , Animais , Bovinos , Feminino , México , Parto , Gravidez , ReproduçãoRESUMO
Climate change is a major world-wide challenge to livestock production because food security is likely to be compromised by increased heat stress of the animals. The objective of this study was to characterize, using bioclimatic indexes, two livestock regions located in an arid zone of México, and to use this information to predict the impact of global warming on animal production systems of these regions located in the state of Baja California (México). A 5-year database (i.e., 2011 to 2015) consisting of about one million data points from two zones (i.e., coast, valley) from four meteorological stations in the north of Baja California were used. Bioclimatic indexes were constructed for the four types of livestock production systems most common in this region, being: dairy cattle, beef cattle, sheep, pigs. The temperature-humidity index (THI) thresholds used to classify heat stress were determined and scaled for each livestock species as: THIbeef and THIpig 74 units; THImilk 72 units; and THIsheep 23 units. Statistical differences between indices were detected (P < 0.01) during summer for the valley and coast zones as (THIbeef = 72.9 and 51.8; THImilk = 80.6 and 67.4; THIpigs = 83.9 and 65.2; THIsheep = 29.5 and 20.1 units). Coast zone weather did not suggest vulnerability of livestock production systems to heat stress at any time of the year, but heat stress risk during summer for valley zone dairy cattle, sheep and pigs was classified as severe, but lower for feedlot cattle. Prediction models showed significant adjustment just in the coastal zone for THImilk, THIsheep, and THIsheep, suggesting more impact of global warming during summer in the coastal zone. Use of management strategies to reduce heat load of domestic animals during summer in northern Baja California is essential to maintain their productivity, with more emphasis in the valley zone.
Assuntos
Mudança Climática , Transtornos de Estresse por Calor , Animais , Bovinos , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Umidade , Gado , México , Ovinos , SuínosRESUMO
The objective was to characterize milk yield and composition from mixed-breed goats kidding in winter and grazing rangelands with 221 (n = 15), 334 (n = 20), or 441 (n = 12) mm of annual rainfall in northern Mexico (22-25°N). Weekly milk yield and composition were recorded and progeny growth performance assessed. Body weight loss during lactation was the highest (6.4 kg) for goats on rangeland with 441 mm of rainfall than goats on 221 mm (1.6 kg), or 334 mm (1.8 kg; P < 0.01). The highest daily milk yield was for goats on 221 mm (498 mL; P < 0.01). There was not an evident peak of lactation and milk yield increased uninterruptedly at the end of lactation. Milk fat was negatively related to milk yield and goats on rangeland with 334 mm had the greatest milk fat content (P < 0.001). Milk protein and lactose content were higher in goats on rangeland with 221 mm (P < 0.01). Goat kids on rangelands with 221 and 441 mm grew faster and were heavier (P < 0.001) at weaning than kids reared in other rangelands. Weaning weight was positively related to milk yield (P < 0.001); but not milk components (P > 0.05). In conclusion, moderate milk yield of mixed-breed goats on rangeland is feasible with parturitions in winter, and milk yield is not affected by reduced annual precipitation in rangelands of northern Mexico. Offspring growth performance depends on maternal milk yield, but not milk composition. Nevertheless, slow growth to weaning of offspring had adverse effects on time to reach adequate market weight.
Assuntos
Cabras/fisiologia , Leite/metabolismo , Criação de Animais Domésticos , Animais , Peso Corporal , Feminino , Cabras/genética , Lactação , Lactose/metabolismo , México , Leite/química , Parto , Gravidez , Chuva , Estações do AnoRESUMO
The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P4) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500â¯×â¯106) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (Pâ¯<â¯0.05) in bitches with >23â¯kg than bitches with <23â¯kg (83.9 vs 63.8%). Whelping rate was greater (Pâ¯<â¯0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (Pâ¯<â¯0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4â¯mL or >4â¯mL of semen). Litter size was larger (Pâ¯<â¯0.05) in bitches >23â¯kg than lighter animals (3.72⯱â¯1.79 and 2.30⯱â¯1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P4 concentration and infusion of oxytocin in the uterus at AI (Pâ¯>â¯0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4â¯mL semen volume maximize whelping rates in this breed of dogs.
Assuntos
Cruzamento , Cães , Infertilidade/etiologia , Inseminação Artificial , Animais , Líquidos Corporais , Peso Corporal/fisiologia , Cruzamento/métodos , Feminino , Fertilidade/fisiologia , Infertilidade/veterinária , Inseminação Artificial/métodos , Inseminação Artificial/veterinária , Tamanho da Ninhada de Vivíparos , Masculino , Ocitocina/análise , Gravidez , Fatores de Risco , Sêmen/citologia , Sêmen/fisiologia , Resultado do Tratamento , Vagina/química , Vagina/citologia , Vagina/cirurgiaRESUMO
The main cause of death in newborn lambs is hypothermia, so is necessary to identify the factors affecting variations in body surface temperatures of sheep neonates because approximately 60% of their body heat losses occur through the skin. This study aimed to establish relationships among body surface thermography from different regions with rectal temperature (RT), birth weight (BW) and climatic variables in hair breed newborn lambs during early spring in an arid region. Data of body surface temperatures measured by infrared thermography (entire head, eye, muzzle, ear, entire body, shoulder, rump, loin, right flank, belly and leg), RT and BW were collected at 0, 12 and 24â¯h post-lambing in 85 lambs born in early spring. Relative humidity [RH], temperature [Te] and temperature-humidity index [THI] were also recorded. RT was not correlated with surface temperatures at 0 and 24â¯h, but it was at 12â¯h with all of them (0.36â¯≤â¯râ¯≤â¯0.44). BW and some surface temperatures were negatively correlated at 0 and 24â¯h (-0.24â¯≤â¯râ¯≤â¯-0.30), but positively at 12â¯h (0.25â¯≤â¯râ¯≤â¯0.27). All surface temperatures were positively correlated (0.51â¯≤â¯râ¯≤â¯0.85) with Te and THI in the three sampling times. Principal component (PC) analysis showed that PC1 explained the majority of the variance (71-72%), followed by PC2 (8-9%) at 0, 12 and 24â¯h. Body surface temperatures increased as Te and THI also increased, but decreased with the increase in HR. In conclusion, under early spring environment (predominantly cold), the variations in body surface temperatures of hair sheep neonates were more closely related to climatic variables than to RT and BW. Thermography proved to be an effective tool to determine body heat loss by radiation in skin of neonate lambs.
Assuntos
Carneiro Doméstico/fisiologia , Termografia/veterinária , Animais , Animais Recém-Nascidos , Peso ao Nascer , Temperatura Corporal , Regulação da Temperatura Corporal , ClimaRESUMO
Vulnerable animals to heat stress have been described as ones with dark or black hides due to increasing absorption of solar radiation. The effect of coat color in pluriparous contemporary Holstein cows in a hot environment (mean annual temperature 24.6⯰C), on body surface temperature (infrared thermography), physiological and hematological variables as well as milk yield and reproductive performance was assessed using 178 Holstein pluriparous cows (74 predominantly white and 104 predominantly black). Data were collected in the morning and afternoon in July (mean temperature-humidity index 82 units). Body condition score at mid-lactation (128⯱â¯32 days in milk at the start of the experiment) was higher (Pâ¯<â¯0.01) in predominantly white than in black cows (3.3 vs. 3.2). Respiration rate did not differ between groups (72⯱â¯23 vs. 73⯱â¯20 breaths/min for white and black cows, respectively, sampling time combined). In contrast, rectal temperature of black cows was 0.1⯰C higher (Pâ¯≤â¯0.01) than white cows, regardless of sampling time. The only significant hematologic change was a slight increase in mean corpuscular volume in black cows (54.7â¯fL, Pâ¯<â¯0.01) compared to white cows (53.8â¯fL), but it remained within the reference range. Differences due to coat color did not alter body surface temperatures at any time of the day. Conception rates, services per conception, calving intervals and fetal losses were not associated with hair coat color, but cows with predominantly white coat produced 394â¯kg more (Pâ¯<â¯0.01) fat-corrected milk in 305 days compared to cows with predominantly black coat. It was concluded that in this hot-arid environment with cows housed in facilities with extensive cooling, black hair coat moderately reduces 305-d milk yield without affecting milk composition, body surface temperature, and reproductive performance.
Assuntos
Temperatura Corporal , Bovinos/fisiologia , Cor de Cabelo/fisiologia , Resposta ao Choque Térmico , Leite/metabolismo , Reprodução , Animais , Feminino , Fertilização , Temperatura Alta , Lactação , Leite/química , Paridade , GravidezRESUMO
Forty Dorper × Pelibuey sheep females were used to evaluate the effects of physiological state on physiological variables and serum concentrations of metabolites, thyroid hormones, and electrolytes under outdoor heat stress conditions. Females were selected as follows (n = 10 per group): weaning ewe lambs (WEL; 3 months old), replacement nulliparous ewes (RNE; 8 months old), non-pregnant and non-lactating multiparous ewes (NME; 3-4 years old) and lactating multiparous ewes (LME; 3-4 years old). While physiological variables were measured both morning and afternoon, blood samples were collected before feeding in the morning to determine all blood components. Three contrasts were constructed: (1) WEL vs. older ewes, (2) RNE vs. multiparous ewes, and (3) NME vs. LME. Compared with older ewes, WEL had higher (P < 0.01) rectal temperature (RT) and hair coat temperatures through the day, and also higher (P < 0.01) respiratory rate (RR) only in the afternoon. Serum levels of glucose and cholesterol were lower (P ≤ 0.02) in WEL than in older ewes. Nulliparous ewes compared with multiparous had always similar RT but higher (P ≤ 0.05) hair coat temperatures in most of the body regions by the morning and higher (P < 0.01) RR, without difference for hair coat temperatures in the afternoon. Only serum glucose (P = 0.07) and urea nitrogen (P < 0.01) levels were affected by parturition number, being lower in multiparous ewes. Regarding the effect of lactation, while RR was unaffected, afternoon RT and hair coat temperatures in most of the body regions through the day were higher (P ≤ 0.03) in lactating ewes. In addition, LME had lower (P < 0.01) serum levels of glucose, cholesterol, and urea nitrogen, but higher (P = 0.02) triiodothyronine levels than NME. In conclusion, ewe lambs and lactating ewes were less tolerant to heat stress, while nulliparous and multiparous ewes showed similar thermoregulatory ability.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Transtornos de Estresse por Calor/fisiopatologia , Transtornos de Estresse por Calor/veterinária , Doenças dos Ovinos/fisiopatologia , Ovinos/fisiologia , Envelhecimento/fisiologia , Animais , Glicemia/análise , Temperatura Corporal , Colesterol/sangue , Feminino , Transtornos de Estresse por Calor/sangue , Paridade , Gravidez , Taxa Respiratória , Doenças dos Ovinos/sangueRESUMO
The aims of the present study were to investigate (1) the risk factors that influence the occurrence of clinical ketosis (CK; blood ß-hydroxybutyrate > 3.0 mmol/L) and (2) to determine the influence of subclinical ketosis (SCK; 1.2 ≤ ß-hydroxybutyrate ≤ 2.9 mmol/L) and CK on reproductive performance and milk yield in high-yielding Holstein cows in a hot environment. Cows (n = 345) were blood sampled from 6 to 15 days postpartum for ß-hydroxybutyrate (BHB) determination with a hand-held meter. Cows calving in spring had 3.7 increased odds of having CK (20.7% incidence) than cows calving in summer (3.9% incidence) and autumn (9.4% incidence). Temperature-humidity index < 83 was associated with 1.6 times higher risk for CK compared with cows calving in warmer days. First-service conception rate was 12 and 16 percentage point higher (P < 0.05) in nonketotic cows compared with cows with SCK and CK, respectively. Actual 305-day milk yields for healthy, SCK, and CK cows were 9991 ± 1411, 10,123 ± 1442, and 10,386 ± 1435 kg (mean ± SD), respectively, with no difference (P > 0.05) between groups. In conclusion, this study documented that ketosis was seasonal with lower incidence of this metabolic disease during hot seasons and with increased ambient temperature at calving. Also, 305-day milk yield of Holstein cows was not related to blood BHB content early in lactation in this hot environment. However, elevated circulating BHB was negatively associated with conception rate at first service and fetal losses.
Assuntos
Doenças dos Bovinos/epidemiologia , Bovinos , Indústria de Laticínios/métodos , Cetose/epidemiologia , Leite/metabolismo , Ácido 3-Hidroxibutírico/sangue , Animais , Doenças dos Bovinos/metabolismo , Clima , Feminino , Fertilização , Temperatura Alta , Incidência , Cetose/veterinária , Lactação , Período Pós-Parto , Reprodução , Fatores de Risco , Estações do AnoRESUMO
This study aimed to investigate the effect of heat stress and month of birth on growth performance, pelleted starter intake, and stress-related hormones in Holstein calves. Birth weight and growth records, representing 4735 Holstein calves from a large commercial dairy herd in northern Mexico (25° N; 22.3 °C mean annual temperature) from 2013 to 2015, were analyzed. Temperature-humidity index (THI) at calving, season of birth, and month of birth were the independent variables, whereas growth traits were the dependent variables. Increased THI at birth from < 65 to > 85 units was associated with a decrease in birth weight from 39.3 to 38.7 kg. Calves subjected to high THI (> 75 units) at calving showed lesser (P < 0.01) pre-weaning gains (405 ± 97 g/calf/day), whereas those calves born with THI < 70 units presented the highest gains (466 ± 112 g/calf/day). Birth during the fall months reduced (P < 0.01) weaning weight by about 5 kg compared with winter months. Also, the pre-weaning average daily gain for calves born in the fall was about 70 g less (P < 0.01) than calves delivered in winter months. Plasma triiodothyronine and tetraiodothyronine levels were lower (1.02 ± 0.21 and 48 ± 7.9 ng/mL, respectively; P < 0.01) in summer and highest in winter (1.64 ± 0.48 and 66 ± 11 ng/mL, respectively). Mean plasma cortisol concentration was higher in heat-stressed calves born in summer (59 ± 40 ng/mL) than calves born in winter (20 ± 28 ng/mL). Pelleted starter intake 1 week before weaning was lowest (P < 0.01) in the fall (0.82 ± 0.26 kg/calf/day; mean ± SD) and highest in spring (1.26 ± 0.43 kg/calf/day). It was concluded that in this particular environment, heat stress affects birth weight and growth rate of Holstein calves. Thus, environmental management of the newborn calf during hot spring and summer months is warranted to optimize pelleted starter intake and calf growth rates.
Assuntos
Doenças dos Bovinos , Transtornos de Estresse por Calor , Ração Animal , Animais , Peso Corporal , Bovinos/sangue , Bovinos/crescimento & desenvolvimento , Doenças dos Bovinos/sangue , Ingestão de Alimentos , Feminino , Transtornos de Estresse por Calor/sangue , Transtornos de Estresse por Calor/veterinária , Umidade , Hidrocortisona/sangue , Temperatura , DesmameRESUMO
Two trials were conducted to evaluate the effect of diverse socio-sexual cues upon male sexual behavior and the reproductive performance of anestrous does (AD). Trials were conducted in northern Mexico (26°N) during the natural anestrous season (Feb-Mar) with crossbred dairy bucks. In Experiment 1, sexually inactive bucks (SIB, n=12) were randomly allotted to three groups, four males/group: a) DEE 9novelty stimulation) - daily exchange of estrogenized females (EF) 12&12h, b) NEE (no novelty stimulation) - no-exchange of EF, 24h, or c) CON (saline-treated_ -daily exchange of AF 12&12h. Sexually active bucks (SAB) from the DEE, NEE and CON groups were subsequently exposed to AD (n=72; n=24/group) and the reproductive outcomes were recorded. In Experiment 2, SAB (n=12; n=6/group) were randomly divided in: 1) B+EF - males+four-EF exposed to AF (n=36), and 2) B+NEF; males+four-saline-treated AD and exposed to AD (n=36). Prior to the onset of the experimental breeding in both experiments, the investigative (ISB), consummatory (CSB) and resting (RSB) sexual behavior of males were quantified (2h×d×2d). Sexual behaviors considered were: ISB - flehmen, ano-genital sniffing, approaches, vocalizations, kicking, penis extrusion, CSB; mount attempts and mounts, and RSB - isolation, attempted escape, aggression and distractions. While EF were an effective stimulus (P<0.05) for evoking mounting in SIB males, daily exchange of estrous does used to stimulate males promoted an enhanced response (P<0.05) in terms of both ISB and CSB. After being exposed to AD, the B+EF bucks induced an earlier estrous response (P<0.05) as compared with the B+NEF bucks. The untreated females did not induce any sexual activity in males and stimulation of ovarian function did not occur when saline treated (CON) AD were exposed to AD. Also, the B+EF group induced an enhanced increase (P<0.05) of the male ISB and CSB, inducing in turn an increase percentage onset of estrus in does that had previously been anestrus (P<0.05).
Assuntos
Estro/fisiologia , Cabras/fisiologia , Comportamento Sexual Animal/fisiologia , Animais , Feminino , MasculinoRESUMO
The scales of perceived exertion (PE) quantify the perceptual changes induced by physiological stress during exercise. Whereas the adult scales cannot be used in children, it was built the EPInfant scale for Spanish speaking children. The aim of this study is to determine the validity of the criteria for an exercise test on a treadmill. Methods: Cross-sectional study, in which the criterion validity was determined by linear regression between the EP and variable intensity exercise (heart rate and workload) during incremental exercise test in treadmill (Naughton’s test). Results: At study entered 26 healthy children (13 males) with a mean age of 13.6 ± 0.13 years-old. Both the PE and heart rate (HR) increased significantly at every level of intensity during the Naughton’ test. It was observed a strong linear correlation between the PE and HR, as well as between PE and workload (speed and slope of the treadmill). All regression models were highly significant (p < 0.0001). Conclusion: EPInfant scale has an acceptable criterion-related validity to measure PE during an incremental exercise test on a treadmill in the studied sample of children. Future studies are needed to determine other properties of measurement in this type of exercise.
Introducción: Las escalas de esfuerzo percibido (EP) permiten cuantificar los cambios perceptuales inducidos por el estrés fisiológico durante el ejercicio. Considerando que las escalas de EP para adultos no pueden ser utilizados en niños, se construyó la escala EPInfant. El objetivo de este estudio fue determinar su validez de criterio durante una prueba de ejercicio en cinta rodante. Métodos: Estudio de corte transversal. Se determinó validez de criterio concurrente aplicando regresión lineal entre EP y variables de intensidad de ejercicio (frecuencia cardíaca (FC) y carga de trabajo), durante la prueba de ejercicio incremental en cinta rodante (test de Naughton), en población infantil sana de la ciudad de Concepción Chile. Resultados: Se estudiaron 26 sujetos (13 varones), con una media de edad de 13,6 ± 0,13. Tanto la FC como el EP incrementaron significativamente en cada nivel de intensidad durante el test de Naughton. Se verificó correlación lineal entre el EP y FC; así como también, entre EP y carga de trabajo (velocidad e inclinación de la trotadora). Todos los modelos de regresión fueron significativos (p < 0,0001). Conclusión: La escala EPInfant posee una adecuada validez de criterio concurrente para medir EP durante el test de Naughton en la muestra estudiada. Se requieren estudios adicionales para determinar otras propiedades de medición en esta modalidad de ejercicio.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Teste de Esforço , Exercício Físico/fisiologia , Frequência Cardíaca/fisiologia , Esforço Físico/fisiologia , Demografia , Modelos Lineares , Percepção , Reprodutibilidade dos TestesRESUMO
This study aimed to determine the possible effects of a single injection of human chorionic gonadotropin (hCG) as a means for estrus induction in acyclic French-Alpine goats during the reproductive transition period at 25°N, 103°W. The potential effects of hCG upon ovarian function and reproductive performance of goats were also assessed. Multiparous acyclic French-Alpine goats (n = 39; 37.4 ± 8 .5 kg) were primed with 20mg progesterone (P4) 1 day prior to hCG administration. Thereafter, does were treated either with saline (hCG-0; n = 10), 50 (hCG-50; n = 9), 100 (hCG-100; n = 10), or 300 IU of hCG (hCG-300; n = 10). Ovarian structures and pregnancy were monitored by transrectal ultrasonography. In addition, after hCG application, goats were monitored twice daily (0800 and 1800 h) to detect estrus signs, with the use of aproned, sexually active bucks treated with testosterone. Goats were bred 12h after the onset of estrus. Two days after hCG administration, the number of large follicles was higher (P < 0.05) in the hCG-50 and hCG-300 groups (1.7 ± 0.1 and 1.8 ± 0.2, respectively) compared with the hCG-100 and hCG-0 groups (1.4 ± 0.2 and 1.1 ± 0.1, respectively). Although none of the hCG-0-goats depicted estrus, the estrus response from the hCG-50, hCG-100, and hCG-300 groups over the 7-d breeding period was 67%, 100%, and 90%, respectively (P > 0.05), being always accompanied by ovulation. Pregnancy rate (67, 100, and 70%), kidding rate (55%, 80%, and 70%), and litter size (1.6 ± 0.5, 1.5 ± 0.5, and 1.5 ± 0.5) for hCG-50, hCG-100, and hCG-300, respectively, did not differ among the hCG-treated does. Therefore, the combined use of P4-priming plus a 100-IU hCG injection is an effective protocol for inducing estrus in non-cycling Alpine goats during the anestrus-to-estrus transition period, which is of key importance for both goat producers and industrializers.
Assuntos
Gonadotropina Coriônica/farmacologia , Ciclo Estral/efeitos dos fármacos , Cabras/fisiologia , Progesterona/farmacologia , Substâncias para o Controle da Reprodução/farmacologia , Animais , Feminino , GravidezRESUMO
Twenty Dorper × Pelibuey primiparous ewes were used to evaluate effects of seasonal ambient heat stress (i.e., spring vs. summer) on physiological and metabolic responses under production conditions in an arid region. Ten ewes experiencing summer heat stress (i.e., temperature = 34.8 ± 4.6 °C; THI = 81.6 ± 3.2 units) and 10 under spring thermoneutral conditions (temperature = 24.2 ± 5.4 °C; THI = 68.0 ± 4.8 units) were corralled together to measure rectal temperature, respiratory frequency, and skin temperatures at 0600, 1200, 1800, and 2400 h on four occasions over 40 days. Blood metabolite and electrolyte concentrations were also measured at 0600 and 1800 hours. Data were analyzed with a completely randomized design using repeated measurements in time. Rectal and skin temperatures, as well as respiratory frequency, were higher (P < 0.01) in summer than spring at all measured days. Blood serum glucose, cholesterol, triglycerides, and chlorine concentrations were lower (P < 0.01) in summer than spring at 0800 and 1800 hours. In contrast, summer heat stress increased (P < 0.01) blood urea and potassium concentrations at 0800 and 1800 hours. Compared with spring thermoneutral conditions, summer heat stress affected the physiological and metabolic status of hair breed ewes in an arid region, which included blood metabolite and electrolyte adjustments to efficiently cope with summer heat stress.
Assuntos
Transtornos de Estresse por Calor/veterinária , Temperatura Alta/efeitos adversos , Ovinos , Estresse Fisiológico , Animais , Glicemia/análise , Temperatura Corporal , Colesterol/sangue , Clima , Feminino , Transtornos de Estresse por Calor/sangue , Transtornos de Estresse por Calor/fisiopatologia , Umidade , Potássio/sangue , Taxa Respiratória , Estações do Ano , Ovinos/sangue , Ovinos/fisiologia , Triglicerídeos/sangue , Ureia/sangue , VentoRESUMO
The aim of this study was to determine, using multiple logistic models, factors affecting pregnancy per AI (P/AI) following fixed-time artificial insemination (FTAI) in repeat breeders cows (RBC) treated with rbST throughout lactation. 498 RBC received a CIDR device and 100µg of GnRH on day 0. CIDR removal and PGF(2α) (25mg) treatment were done concurrently on day 7. Estradiol benzoate (EB, 1mg) was injected on day 8 and GnRH on day 9; cows were inseminated 16-20h later. Cows with an average milk protein <3% were 43% more likely (P<0.05) to become pregnant at FTAI than cows with milk protein ≥3%. Cows with <6 services had significantly increased chances of becoming pregnant than cows with ≥6 services at FTAI (P/AI 36 vs. 27%; P<0.05). CIDR-treated cows with less than three lactations were 1.7 times more likely (P/AI 35 vs. 21%; P<0.05) to become pregnant than cows in third or greater lactation. Cows with peak milk yields lower than 55kg were 1.5 times more likely to get pregnant than cows with peak milk yields greater than 55kg (P/AI 37 vs. 28%; P<0.05). P/AI was lower (30 vs. 35%; P<0.01) for cows with dry periods <62 days than cows with dry periods ≥62 days. Cows subjected to FTAI with a temperature-humidity index (THI) <76 were 45% more likely (P<0.05) to become pregnant than cows inseminated at a THI≥76. It was concluded that an acceptable proportion (32%) of RBC can become pregnant with the protocol used in the present study. Also, subfertility in CIDR-treated cows was associated with high peak yields, high milk protein, increased service, increased lactation, high THI at AI and short dry periods.
Assuntos
Bovinos , Inseminação Artificial/veterinária , Indução da Ovulação/métodos , Resultado da Gravidez/veterinária , Prenhez , Administração Intravaginal , Animais , Cruzamento/métodos , Bovinos/fisiologia , Causalidade , Indústria de Laticínios , Sincronização do Estro/métodos , Feminino , Inseminação Artificial/fisiologia , Dispositivos Intrauterinos Medicados/veterinária , Indução da Ovulação/veterinária , Paridade/fisiologia , Gravidez , Resultado da Gravidez/epidemiologia , Progesterona/administração & dosagemRESUMO
Records representing data from 1,500 barren Holstein cows over an 8-yr period from a large commercial dairy farm in northern Mexico were analyzed to determine the effects of lactation number and season and year of initiation of lactation on milk production of cows induced hormonally into lactation and treated with recombinant bovine somatotropin (rbST) throughout lactation. Peak and 305-d milk yields were also assessed as predictors of total milk yield in cows induced into lactation. A significant quadratic relationship was found between 305-d milk yield and number of lactation [7,607±145 and 9,548±181 kg for first- and ≥6-lactation cows, respectively; mean ± standard error of the mean (SEM)] with the highest production occurring in the fifth lactation. Total milk yields of cows with ≤2 lactations were approximately 4,500 kg less than milk yields of adult cows (the overall average ± standard milk yield was 13,544±5,491 kg per lactation and the average lactation length was 454±154 d). Moreover, 305-d milk production was depressed in cows induced into lactation in spring (8,804±153 kg; mean ± SEM) and summer (8,724±163 kg) than in fall (9,079±151 kg) and winter (9,085±143 kg). Partial regression coefficients for 305-d milk yield and peak milk yield indicated an increment of 157 kg of milk per lactation per 1-kg increase in peak milk yield (r(2)=0.69). Neither peak milk yield (r(2)=0.18) nor 305-d milk yield (r(2)=0.29) was accurate for predicting total milk yield per lactation. Year, parity, and season effects had significant influence on milk yield of cows induced into lactation and treated with rbST throughout lactation, and peak milk yield can assist in the prediction of 305-d milk yield but not total milk yield. This study also showed that hormonal induction of lactation in barren high-yielding cows is a reliable, practical, and affordable technique in countries where rbST treatment and prolonged steroid administration of dairy cows are legally permitted.