Correlation Of Infrared Thermography With Performance Measures Of Dorper Lambs

The development of new tools for animal production studies has been increasing at a fast pace in the areas of nutrition and well-being. Infrared thermography is a non-invasive technique with accessibility and practicality, which can be used to obtain results from the selection of animals in intensified sheep farming. The experiment was carried out at the Instituto de Zootecnia de Nova Odessa, with the objective of correlating the average temperatures of different regions of the body through infrared thermography with measures of consumption in a food efficiency test. We evaluated 26 male Dorper lambs, weaned, not castrated and with average initial weight of 28.9 ± 3.2 kg. Thermographic images were obtained from each animal at a fixed distance of 60 centimeters (cm), at the following sites: eyeball (TMEDOC), snout (TMEDFOC), distal region of the hind limb (hoof) (TMEDC), testis (TMEDT) and rumen (TMEDRUM), with the aid of a FLIR E96 thermographic camera, calibrated to emissivity of 0.95, with subsequent analysis and adjustment using the FLIR Thermal Studio software. In each image, a marker with localized average temperature was used, with the shape of an ellipse for all regions. Subsequently, the animals were confined in a shed with an Intergado® System with 9 automated troughs to measure individual food consumption for 45 days, after adaptation to food and the environment for 15 days. Pearson’s correlation coefficients were calculated using the average temperature of the body sites, initial age and consumption (SAS). The averages obtained for the eye, snout, hoof, testis and rumen temperatures were 36.37 ºC ± 0.76 ºC, 30.26 ºC ± 4.75 ºC, 24.69 ºC ± 4.14 ºC, 30.06 ºC ± 1.69 and 30.71 ºC ± 1.91, respectively. The averages of initial age (IDINIC) and consumption (CONS) were 123.30 d ± 16.30 d and 1.15 kg ± 0.26 kg, respectively. TMEDRUM presented a coefficient of 0.52 with IDINIC (P<0.05), while. TMEDFOC showed a medium-high and positive correlation (r = 0.51) with consumption (P<0.05). TMEDOC, TMEDC and TMEDT showed no significant correlations with any of the characteristics evaluated. The correlations obtained from the average temperatures in the snout and rumen regions of the animals with the initial age and consumption, respectively, indicated that these sites can be selected to capture and analyze thermographic images in Dorper lambs, in studies related to animal feeding, corroborating research results in ruminant nutrition

Correlation of Zoometric Indices and Morphometric Measurements in Dorper Lambs

Many studies have been conducted to identify animals with good ability for meat production. In this respect, morphometric measurements and zoometric indices are important tools to select many characteristics aiming at animal genetic improvement, increasing the profitability and sustainability of animal production. This study was carried out at the Sheep Unit of the Instituto de Zootecnia in Nova Odessa, São Paulo, Brazil, with the objective of correlating zoometric indices and morphometric measurements in Dorper lambs. We used 26 registered uncastrated male lambs, with mean age of 102.30 ± 16.30 days and mean weight of 26.10 ± 4.14 kg. The weight was measured with mechanical scale and morphometric measurements were performed with a tape measure and a hypometer. The morphometric measurements collected were withers height (HW), rump height (HR), body length (BL), thoracic perimeter (TP) and rump width (RW). The zoometric indices were calculated by the morphometric measurements body index (BI), relative body index (RBI), thoracic perimeter-withers height ratio (TPRI), and body capacity index (BCI). Pearson's correlation coefficients were obtained using the average of morphometric measurements and zoometric indices, through the SAS software (Statistics Analyses System). The averages for HW, HR, BL, TP and RW were 52.65 ± 2.68 cm, 52.19 ± 2.75 cm, 59.83 ± 2.83 cm, 70.13 ± 4.71 cm, 25.43 ± 2.15 cm respectively. The values of the indices were 85.49 ± 4.12 %, 113.81 ± 6.14 %, 133.36 ± 8.90 % and 46.35 ± 5,45 kg/cm for BI, RBI, TPRI and BCI respectively. There was medium-high correlation (p<0.05) of withers height and BI (r = - 0.59), TPRI (r= 0.61), and BCI (r= - 0.44), respectively. Rump height also showed correlation (p<0.05) with BI (r= -0.45), RBI (r= 0.49) and BCI (r= -0.42). At the same rate, body length showed positive medium-high correlations (p<0.05) with BI (r=0.52) and RBI (r=0.49). There was a high correlation coefficient also (p<0.0001) for thoracic perimeter and TPRI (r = 0.85), and BCI (r = 0.40). The results obtained confirmed that zoometric indices and morphometric measurements are correlated and important to apply for characterization of the sheep herds, providing important data for selection and animal genetic improvement, an important factor for production intensification

Evaluation of Morphometric Measurements of Dorper Lambs of Different Age Groups

Morphometric measurements are easy tools to adopt for characterization of breeds, as well to select the best animals for breeding. Therefore, the objective of this study was to characterize the morphology of Dorper lambs of different age groups. The study was conducted at Sheep Unit of the Instituto de Zootecnia, located in Nova Odessa, SP. A total of 26 registered uncastrated male lambs from nine sheep farms in three different states (São Paulo, 7; Santa Catarina, 1; Paraná, 1) were used. The average age was 102.30 ± 16.30 days and average body weight was 26.10 ± 4.14 kg. Initially, the animals were weighed (kg) and then 13 morphometric traits were measured: withers height (WH), rump height (RH), withers depth (WD), rump depth (RD), chest width (CW), withers width (WW), rump width (RW), body length (BL), chest girth (CG), rump girth (RG), shoulder girth (SG), leg girth (LG) and scrotal circumference (SC). The lambs were separated into three age groups, divided according to ± 0.5* age standard deviation: AG1 (67 to 93 days, n = 9), AG2 (99 to 105 days, n = 8) and AG3 (112 to 135 days, n = 9). The effect of age group was used to compare the morphometric measurements by the Tukey test at 5% significance (SAS). No significant differences were identified according to the age groups. However, some measures of the AG3 group had lower values (CW = 23.42 ± 1.70; WW = 23.65 ± 1.60; RW = 25.82 ± 1.79; BL = 59.45 ± 2.97; CG = 69.33 ± 4.5; RG = 69.45 ± 4.47; and SG = 23.73 ± 1.34; LG = 36.47 ± 3.58), although the lambs were older. Therefore, the morphometric characterization of Dorper lambs did not differ using a 72-day interval

Zoometric indices in dorper lambs of different age groups

The zoometric indices can provide information related to the productivity of a herd. With these indices it is possible to classify the capacity for meat production and select the best animals for sustainable animal production. Thus, the objective of this study was to evaluate zoometric indices in Dorper lambs confined in different age groups. The study was carried out at the Sheep Unit of the Instituto de Zootecnia, in Nova Odessa, SP, with 26 registered uncastrated male lambs, from nine farms in the states of São Paulo (7), Santa Catarina (1), and Paraná. (1), with mean age of 102.30 ± 16.30 days and mean weight of 26.10 ± 4.14 kg. The animals were separated into three age groups: group 1 (67 to 93 days, n=9), group 2 (99 to 105 days, n=8), group 3 (112 to 135 days of age, n=9). The animals were confined with access to a trough containing high concentration diet with 15% fiber. The averages of zoometric indices were obtained by morphometric measurements. The weight assessment was performed using a mechanical scale and morphometric measurements were performed with a tape measure and a hypometer. The following zoometric indices were calculated: body index (BI), relative body index (RBI), thoracic perimeter withers ratio (TPWR), and body capacity index (BCI). For normally distributed data, comparison of the means according to age groups was performed with the Tukey test at 5% probability (SAS). The zoometric indices showed no differences (p>0.05) between age groups, with averages of BI (85.49% ± 4.12%), RBI (113.81% ± 6.14%), LBI (88.10% ± 4.70%), TPWR (133.36% ± 8.90%), and BCI (46.35 ± 5.45 kg/cm). The results showed no differences between age groups for zoometric indices, but the values obtained from the indices showed that the group was composed of animals classified as midline, with little leg development and good development of the thoracic region, allowing good meat production by Dorper lambs, reinforcing that zoometric indices are important to classify the functionality of a herd and select the best animals for sustainable production

Forage Mass and Leaf Area Index in Multispecies Pastures Under Continuous Stocking

The association of different species in a pasture ecosystem is a challenge for grazing management, where the leaf area index (LAI) is the end result of interactions between plant-animal-environment. Therefore, this study evaluated the effects of grazing management strategies (GMS) considering forage canopy heights on forage mass production (FM) and LAI in multispecies pastures. The experiment was conducted at the Instituto of Zootecnia in Nova Odess, SP in autumn (June 2021) and spring (December 2021). Multispecies pastures were composed of aruana grass (Megathyrsus maximum cv. Aruana) and a mix of forage legumes: calopo (Calopogonium mucunoides), macrotyloma (Macrotyloma axillare) and stylo (Stylosanthes macrocephala+ Stylosanthes capitata). The study was conducted in four randomized blocks with four treatments (grazing management strategies – GMS: 15, 30, 45 and 60 cm canopy heights) and four replications (500 m²/each paddock), with continuous stocking of sheep. For the FM evaluation, the forage was cut at soil level in three 0.25 m² areas, representative of the average paddock height. The samples were weighed, homogenized and divided into two subsamples for component separation and total dry matter quantification after drying in a forced-air oven at 65 °C for 72 hours. The leaf area (cm²) was determined using a LI-COR model 3100 measuring device to calculate the total covered soil area (m²) and to find the LAI values for aruana grass (LAIaruana), legumes (LAILeg) and aruana grass + legumes (LAITotal). Analysis of variance was performed by SAS software using proc MIXED. The Tukey test was applied for comparison of means (P<0.05). There was a significant effect for GMS and season in FM (P<0.0001; P=0.00061). The highest FM value found was for 60 cm GMS, with 8883±489.5 kg DM.ha-1, compared to 15 cm with 5714±489.5 kg DM.ha-1, and the largest FM was observed in autumn (7977±346,2) compared to spring (6505±346,2 kg DM.ha-1,). There was interaction between GMS and season for aruana grass leaf blade area (LBAG) and legume leaflet (LL), (P=0,0038; P=0.0060). LBAG and LL presented smaller values for 30 cm GMS during autumn, of 641 and 3± 86,27 kg DM.ha-1. There was seasonal effect (P<0.0001) for the dead material component (DMC), with values of 4412 and 1989± 227.1 kg DM.ha-1, respectively, in autumn and spring. There was a GMS and season effect for LAIaruana and LAITotal (P= 0.0030; P<0.0001, respectively). The highest values of LAIaruana and LAITotal were observed for GMS of 60 cm with values of 4.1 and 4.7, while, the lowest values observed were 2.2 and 2.3 for 15 cm GMS, respectively. The highest values observed for the season were 4.3 and 4.7 during spring for LAIaruana and LAITotal. There was a significant interaction between GMS and season for LAILeg (P= 0.0145), and the highest value was observed for the 60 cm GMS in spring (1.1). Decreasing favorable edafoclimatic conditions and increased grazing pressure by reducing grazing management heights reflected LBGA and LL mass production decrease, contributing to the LAI reduction, but the legumes’ presence increased LAI values. DMC mass presence in unfavorable conditions contributed to the lower LAI values, directly affecting the plants’ photosynthetic apparatus, with lower quantity and quality, impacting forage plant resources. Therefore, FM and LAI were affected by GMS and season. It is not advisable to use grazing management strategies below 45 cm for LAI maintenance, mainly for forage legumes during unfavorable periods

Evaluation of The Proportion of Touches in Botanical Components and Forage Mass in Multispecies Pastures Under Continuous Stocking

The pasture structure consists of the three-dimensional arrangement of botanical and morphological components, shaped by environmental and grazing conditions. Therefore, this study aimed to evaluate the effects of grazing management strategies (GMS) on touch proportion on botanical components during height measurements (TPH) and forage mass (FM) in multispecies pastures. The experiment was conducted at the Instituto de Zootecnia in Nova Odessa, SP in summer (January and February 2021) and winter (June and July 2021). Multispecies pastures were composed of aruana grass (Megathirsus maximum cv. Aruana) and a mixture of forage legumes: calopo (Calopogonium mucunoides), macrotyloma (Macrotyloma axillare) and stylo (Stylosanthes macrocephalla+Stylosanthes capitata). The study was conducted in four randomized blocks with four treatments (15, 30, 45 and 60 cm canopy heights considering the GMS) and four replications (500 m²/each paddock), in continuous stocking with sheep. For the evaluation of TPH, aruana grass leaf blade (PAGLB), legume follicle (PLF) and invasive plants (PIP), the training of observers was first performed later, with a monthly frequency at the time of the 50 readings of the average heights of the paddocks, generating percentage values of participation. For the evaluation of the FM, soil level cutting was performed in three areas of 0.25 m² representative of the average height of the paddocks. The samples were divided into two subsamples for separation of components and quantification of total dry matter. Analysis of variance was performed with PROC MIXED of the SAS software, and the Tukey test was applied for comparison of the means (P<0.05). The TPH of PAGLB, PFL and PIP components was affected by the seasons (P= 0.0013; P<0.0001; P= 0.0403, respectively). The highest values of PAGLB and PIP were found in winter (62±3.1 and 25±2.2%) compared to summer (53±3.1 and 21±2,2%. For PFL, the highest value was found in summer compared to winter (25 and 13±1.7%). For the variable FM and aruana grass mass (AGM), there was an effect of GMS (P= 0.0060; P= 0.0021). The highest values of FM and AGM were for the 60 cm strategy, with 10451± 691.9 and 5675± 448.9 kg of DM.ha-1, respectively, and the lowest values of FM and AGM were for the 15 cm strategy with 7351±691.9 and 3044±448.9 kg of DM.ha-1, respectively. FM, AGM, legume mass (LM) and invasive plant mass (IPM) were affected by the seasons (P<0.0001, respectively for all variables). For FM, AGM, LM and IPM, the highest values found were during summer (10237±546.9; 5758±353.9; 432±61.6 and 714±112.7 kg of DM.ha-1), in relation to winter (7179±399.4; 3019±255.7; 109±43.6; 78±86.6 kg of DM.ha-1). PAGLB and PIP obtained higher values during winter, unlike FM, possibly due to the larger size of these components in winter than summer, which contributes to higher number of touches. For PFL, there was a relationship between its proportion of touches and presence in FM during the summer. This was also due to the fact that calopo and macrotyloma have a twining growth habit and stylo has shrubby habit, which in periods of favorable weather conditions, were able to access the top of the forage canopy, allowing the touch of their structures. The pattern of responses to the relationship between THP and FM needs more studies and has been changed due to the modifications caused by the GMS and environmental conditions in its reflection in the pasture structure

Canopy height impact on legume mass and Megathyrsus maximus tiller dynamics in mixed pastures

The use of grazing management strategies can influence canopy structure and the permanence of legumes. The objective of this work was to evaluate the determination of forage canopy heights as a grazing management strategy regarding herbage mass composition and tiller population dynamics in multispecies pastures comprising Megathyrsus maximus cv. Aruana and the legumes Macrotyloma axillare, Calopogonium mucunoides and Stylosanthes spp. Four treatments, defined by canopy heights of 15, 30, 45 and 60 cm, were evaluated in a randomised block design with four replications. The evaluations were performed under continuous stocking with sheep. Taller pastures (45 and 60 cm) contained greater (P < 0.05) total herbage mass of Aruana leaves and stems and also higher mass of legumes than smaller pastures (15 and 30 cm). The grass tiller population density was different between heights (P < 0.05) of 2.71, 2.02, 1.97 and 1.47 tillers/m2 for heights of 15, 30, 45 and 60 cm, respectively. The tiller appearance rate was highest in tall pastures (P < 0.05) and the lowest rate and stability index were found in 15 cm pastures. Aruana guineagrass and forage legumes can be managed in the height range of 30–60 cm under continuous stocking