Productive, thermoregulatory, and hormonal responses of dairy goats supplemented with selenium-enriched yeast in the Brazilian semi-arid region.

The aim of this study was to evaluate the effect of adding selenium-enriched yeast (SE) in the diet of dairy goats during 60 days of lactation and its effect on productive, thermoregulatory, and hormonal responses of animals managed in a semi-arid region. Sixteen Saanen × Toggenburg crossbred goats were used in a completely randomized design. Goats were weighed, and their milk yield was monitored weekly. Before the animals entered the treatments and at every 20-day milk producing, blood samples were collected to determine the SE levels. At 20, 40, and days of the lactation cycle, individual milk samples were collected to determine composition, casein, urea nitrogen, and selenium content. Measurements of respiratory rate (RR), rectal temperature (RT), coat surface temperature (CST), and epidermal temperature (ET) were performed weekly during the experimental period in two shifts, one in the morning (9 am) and the other in the afternoon (3 pm). No difference (P > 0.05) was detected for body weight, milk yield, composition, selenium concentration, and urea nitrogen. Lower RR and ET (P < 0.05) were observed for animals that received SE supplementation. Thyroid hormone concentrations were similar between treatments (P > 0.05). The positive results of the SE supplementation were concentrated in thermoregulatory responses, and there was no effect on productive, hormonal responses, and plasmatic concentration of selenium in the milk. The SE supplementation for dairy goats managed in a Brazilian semi-arid region was able to promote reduction of RR and coat temperatures.

Thermoregulatory capacity of goat kids from birth to weaning in a dry hot climate.

This study aimed to evaluate the thermoregulatory capacity and performance of Saanen goat kids from birth to weaning in a hot climate. Twelve newborn males and female goat kids with an initial body weight of 4.17 ± 0.81 kg were used. Physiological responses, climatic variables, and biometric traits data were collected. Univariate and multivariate analysis techniques were used. Heart rate (HR) was high up to the 6th week of life, with a reduction from the 7th week on (P < 0.001). Rectal temperature (RT) was lower in the first 2 weeks (P < 0.001), with an increase and stabilization occurring in the 7th and 8th weeks. Coat surface temperature (ST) was more activated from the 5th week onwards (P < 0.001). Body weight (BW) and withers height (WH) were higher in later weeks of the calving phase with a linear effect (P < 0.001). The first principal component demonstrated the relationship of sensible heat dissipation × body area of the goat kids; the second component shows the relationship of meteorological data with RT, having a positive relationship between RT with RH and negative with AT, and the third component points to the association of RR and HR. Of the animals, 81.3% were correctly classified in their group of origin in discriminant canonical analysis, with emphasis on the classification of the kids in the 1st-2nd and 3rd-4th weeks (classification percentage Æ© = 95.8%). It is concluded that (i) newborn kids activate latent mechanisms to maintain their homoeothermic during the first 2 weeks of life, and as they grow, they use sensitive heat loss processes, especially from the 5th week of life onwards and (ii) male and female goats do not show sexual dimorphism effect on body performance and body morphometric measurements up to 60 days of life.

Organic selenium supplementation on metabolic profile of dairy goats.

The aim of this study was to evaluate the effect of organic selenium (SE) supplementation on blood constituents related to hematology and serum biochemistry of dairy goats in the productive phase. A total of 16 lactating Saanen × Toggenburg crossbred goats, aged between 2 and 3, lactating, nonpregnant, clinically healthy, and having a body weight (BW) of 40.75 ± 8.31 kg were selected for this study. Higher SE concentrations were observed on the 42nd day of supplementation, and on the 63rd day, the SE concentrations were similar ([Formula: see text]) to the 21st and 42nd days. There was no interaction for plasma constituents comparing treatment effects and days of supplementation ([Formula: see text]). SE supplementation reduced ([Formula: see text]) plasma proteins with a gradual increase in available SE. There was no difference ([Formula: see text]) for the blood count comparing the effects of treatment and days of supplementation. There was no interaction ([Formula: see text]) for serum biochemical constituents between treatments and periods, except for urea ([Formula: see text]). Animals that received SE supplementation had similar plasma urea concentrations before and after supplementation, while animals that did not receive SE in the diet had increased serum urea concentrations. The main action of selenium in metabolism occurred in the reduction of plasma proteins and urea levels, which leads us to conclude that it influenced protein metabolism. Finally, hematology, liver function, and energy metabolism are not affected by selenium supplementation in dairy goats reared in semiarid conditions.

Effect of a 60-day organic selenium-supplemented diet on the decrease of somatic cell counts in goat milk.

Selenium is an important element in nutrition, showing great potential in the udder health of dairy goats and in the control of subclinical mastitis. However, there are few studies that evaluated the influence of selenium supplementation on subclinical mastitis in goats. The aim of this study was to evaluate the incidence of subclinical mastitis in dairy goats supplemented with organic selenium (Se yeast) in a semi-arid region. Sixteen Saanen × Toggenburg crossbred lactating goats were allocated randomly into two treatments: with and without addition of organic selenium (Se) to the concentrate. Milk samples were collected every 20 days from each udder half to determine the somatic cell count (SSC), chloride content, pH, electrical conductivity, microbiological isolation, composition, and selenium contents. The highest serum selenium concentrations in the blood of these goats occurred at 42 days of supplementation (P < 0.001). Goats which received organic selenium supplementation had higher serum selenium concentrations (P < 0.05). The milk composition variables did not differ (P > 0.05) between the tested treatments, teats, and collections. After 60 days of supplementation, a difference was observed (P < 0.05) between treatments for SSC, chloride content, and pH. Addition of organic selenium to the diet of dairy goats after 60 days of supplementation was promising in reducing the somatic cell count, consequently improving milk quality.

Evaluation of homeothermy, acid-base and electrolytic balance of black goats and ewes in an equatorial semi-arid environment.

The aim of this study was to investigate the influence of environmental conditions and species on thermoregulatory responses, acid-base and electrolyte balance of black goats and ewes in an equatorial semi-arid environment. Ten Canindé goats and seven Morada Nova ewes with black coat color, all multiparous, aged between 2 and 3 years, non-lactating, non-pregnant, and body weight (BW) of 22.84 ± 4.17 kg for goats and 22.60 ± 3.18 kg for ewes were used in this study. Air temperature (AT) and relative humidity (RH) were measured. Respiratory rate (RR), Rectal temperature (RT), sweating rate (SR), hydrogen potential (pH), partial pressure of carbon dioxide (PCO2), venous oxygen pressure (PO2), bicarbonate (HCO3), base excess (BE), total carbon dioxide concentration (TCO2), venous oxygen saturation (SO2), sodium (Na+) and potassium (K+) were recorded. Animal species (caprine and ovine) and environmental conditions (Thermoneutral condition, TC and Heat condition, HC) were considered as fixed effects. Univariate and multivariate analysis techniques were used. Differences were observed between the two environmental conditions. Significant changes in all thermoregulatory responses for goats and ewes were observed according to the environmental condition effect. The general means of the species showed that only SR was high in ewes (P < 0.05), following a reverse change when compared to goat SR. For the environmental condition effect, only the blood pH of goats did not change under HC (P < 0.05), while the BE and TCO2 did not change for ewes. The general means of PCO2, HCO3, BE, TCO2 and SO2 were higher in ewes compared to goats. For electrolytic balance, Na + demonstrated elevations in HC. Brazilian black goats and ewes raised in an equatorial semi-arid environment tend to have particular homeothermy, acid-base and electrolytic balance which mostly depend on the environmental conditions they are raised. The results support the changes in physiological mechanisms between black goats and ewes; however, both are locally adapted.

Understanding the dairy production systems in rural settlements in the Brazilian semi-arid region: characterization, typology, and holistic perception.

The objective of this study was to characterize and typify dairy farms and to evaluate society's perception of dairy production in rural settlements in the Brazilian semi-arid region. A questionnaire containing questions related to socioeconomic, livestock, physical, herd management, and production indicators was applied to 17 milk farmers for typological analysis. A second questionnaire was subsequently applied to the same 17 farmers for the holistic perception of dairy farming in rural settlements, in addition to 47 technicians in the area of animal science and 140 laypeople. Milk samples were collected in the settlement's community cooling tank, while the water used for milking management was collected in the milking parlor at the 17 farms. Multivariate analysis techniques and thematic analysis were performed. Three dairy production systems were identified: low production group (0-25 L), medium production group (25-50 L), and high production group (50-100 L). The physicochemical properties (composition, density, and cryoscopy) of milk attended the Brazilian regulation values. The microbiological parameters of milk and water used for milking are at odds with regulations. Regarding the typology, the indicators, livestock, and productivity showed discriminatory power (P < 0.05) between the productive systems. The responses from the segments of society showed different views on dairy production in rural settlements. It is concluded that the dairy farmers have low education and the cleaning product and water used in milking are out of regulation. The livestock and production indicators typified mainly dairy farms, while the holistic perception showed a lack of efficiency in rural extension, ignorance of the potential of the productive system. Finally, the creation of public policies focusing on the development of the milk production system in settlements is recommended.

Development of an animal adaptability index: Application for dairy cows.

The objective of this study was designed to evaluate the association between thermoregulatory responses, hormonal, hematological and serum biochemical values features aiming to propose an adaptability index (AI) for dairy cows under tropical conditions. Thirty adult dairy cows were used, including 15 Sindi and 15 Girolando breeds with mean weight of 338.52 ± 42.79 kg and 487.54 ± 60.67 kg, respectively. These data included rectal temperature (RT) and respiratory rate (RR). For the serum of blood sample, the levels of glucose (GLU), cholesterol (CHO), triglycerides (TRI), total protein (TP), creatinine (CRE), albumin (ALB), urea (URE), aspartate aminotrasferase (AST) and alanine aminotrasferase (ALT) and hormonal concentrations (triiodothyronine - T3 and thyroxine - T4). For the total blood samples were analyzed for hematology variables: red blood cell count (RBC); hemoglobin concentration (HC); packet cell volume (PCV); mean corpuscular volume (MCV); white blood cell (WBC). The AI was development using multivariate analysis to "weigh" the influence of each variable in the animal responses. The variables more important for adaptive aspects of Sindi and Girolando cows were respectively: GLU; MCV; AST; PCV; RBC; HE; TP; ALB; ALT; RR; T4; RT; T3; URE; CHO; TRI; CRE; WBC and ALB; GLU; TP; AST; RR; ALT; CRE; CHO; RT; RBC; T4; HE; PCV; MCV; URE; TRI; WBC; T3. The difference between breeds was just over 8% for AI. We developed a preliminary AI, able to measure the level of adaptability of dairy cows under tropical region. The methodological framework has potential to inform decision-makers on the adaptability animal conditions and high inference of the blood values from adaptability of cows.

Adaptive profile of dairy cows in a tropical region.

The objectives of this study were to determine the main variables which act in the adaptive profile and the dynamic of the thermoregulatory responses of Sindi and Girolando dairy cows in tropical conditions using multivariate analyses as the auxiliary method. Thirty dairy cows were evaluated, in which the data were collected monthly during 12 months. Rectal temperature (RT) and respiratory rate (RR) were measured twice a day (morning and afternoon), along with meteorological variables (air temperature, relative humidity, and wind speed), and later the Black Globe and Humidity Index and Radiant Heat Load were calculated. Blood samples were collected for estimating the levels of triiodothyronine (T3), thyroxine (T4), hemoglobin concentration (HC), red blood cells (RBC), packet cell volume (PCV), mean corpuscular volume (MCV), white blood cells (WBC), glucose (GLU), cholesterol (CHO), triglycerides (TRI), creatinine (CRE), total protein (TP), urea (URE), albumin (ALB), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). The more active variables in the adaptive profile for Sindi cows were T4, PCV, RBC, WBC, TRI, CRE, HC, T3, and URE, while PCV, RBC, ALB, TP, RT, RR, URE, ALT, and AST variables were more active for Girolando cows. All animals were classified according to their corresponding group when considering all variables under study. The classification error percentage was > 40% in the Sindi cows when the physiological responses were considered, whereas an 80% success rate was observed in Girolando cows in the winter and summer seasons. The physiological responses of the dairy cows are similar in winter and distinct in summer in tropical conditions.

The dynamic adaptation of Brazilian Brahman bulls.

Heat stress is one of the most important factors that affect the performance of some Bos taurus breeds and crosses in tropical regions. The Brahman breed was developed in hot regions of the world and often has genes that confer resistance to heat stress compared to other breeds of beef cattle. The goal of this work was to evaluate the adaptive responses of Brahman bulls, based on physiological, hormonal and hair characteristics according to season. The physiological, hormonal and hair characteristics were rectal temperature (RT), respiratory rate (RR), sweating rate (SR), triiodothyronine (T3), thyroxine (T4), cortisol concentrations (CO), coat thickness (CT), hair length (HL), hair diameter (HD) and hair density (ND). These were recorded in Brahman bulls from a Cerrado biome during four seasons: spring (21 September to 20 December), summer (21 December to 17 March), autumn (18 March to 20 June) and winter (21 June to 20 September). Data was analyzed using a general linear model that included season as a fixed effect; in addition, multivariate tests and logistic regression were also used to characterize the animals within each season. The meteorological variables defined the four seasons, besides identifying climatic differences between them. Significant differences (P > 0.05) were found for most of the physiological, hormonal and hair characteristics according to season. The Brahman bulls presented particular adaptive characteristics in each season. Individually, most of the Brahman bulls presented the same adaptive reaction in each season; particular similarity occurred for the summer and autumn. This pattern is a reflection of the inter-relationships between physiological responses and hair characteristics.

Economical and financial analysis of lamb finishing fed with diets formulated according to the NRC (1985) and the NRC (2007).

This study compares both versions of the nutritional requirement system determined by the National Research Council (NRC) version 1985 (NRC85) and NRC version 2007 (NRC07), for finishing lambs in feedlots. Nineteen crossbred lambs were divided in four groups representing four experimental treatments: one diet according to NRC85 and three diets according to NRC07. The diets recommended by NRC07 considers crude protein intake relative to ruminal undegradable protein at 20, 40, and 60 % levels (NRC07/20, NRC07/40, and NRC07/60). Diets were composed of Brazilian semi-arid native grass silage, soybean meal, corn, annatto byproduct, and limestone. Purchases and sales of lambs were done according to average market prices in Brazil. The economic indicators considered pointed that all treatments were viable but NRC07/20 and NRC07/60 were more profitable with similar net present values (NPVs) and internal return rates (IRRs). NRC07/20 was the best option showing an IRR of 17.20 % and a payback period (PP) of 5.07 considering a fixed annual interest rate of 6 %. Sensitivity analysis considering a 10 % raise in variable costs showed negative NPVs, IRRs inferior to the opportunity cost rates adopted and PPs that exceeded the planning horizon of 7 years for both NRC85 and NRC07/40.