César Henrique Espírito Candal Poli

Produção de ovinos de corte em quatro sistemas de produção

The potential performance of lambs and ewes from the Suffolk breed in pasture of Tifton grass 85 (Cynodon spp.) and ryegrass (Lolium multiflorum) was evaluated in different production systems: lambs weaned with 60 days and kept in pasture; lambs with ewes and kept in pasture; lambs with ewes and kept in pasture with creep feeding; feedlot confined lambs with alfalfa hay + balanced ration. The treatments were applied when the lambs reached 60 days of age until slaughter time, at 32 kg, and were allocated in a completely randomized experimental design, with three replications. A continuous grazing system, with variable stocking rate, was used in pasture treatments. Important effect of the treatments on performance of the lambs was observed. Feedlot confined lambs showed higher daily weight and at lower age at slaughter time. Creep feeding supplementation at 1% LW, did not have effect in lambs with more than 60 days of age kept with the ewes in Tifton 85 grass pasture. The presence of the ewe in the pasture showed important and positive effect in the individual performance of lambs as compared to lambs weaned at 60 days of age.

From the bite to precision grazing: understanding the plant-animal interface to exploit the multi-functionality of grasslands.

Precision livestock involves innovative technologies to monitor the animal within its pastoral environment. Understanding ingestive behaviour is fundamental to management decisions based upon animal and vegetation monitoring. The way such information can be used is not yet clear. In precision agriculture, the governing principle has been to correct or manage variability so as to homogenise yield at maximized levels. If the same reasoning is applied in livestock production, it can foster classical mistakes in grazing management. However, if precision livestock production can help integrate heterogeneity in managing animals on pasture, then we have a powerful new tool for responding to the new paradigms involving the multi-functionality of grasslands. This paper discusses this concept, and presents the bite as the basic unit of the process to be monitored. A few types of equipment and their application in monitoring site use and the spatial-temporal dynamics of animal biting are presented. The discussion concludes with how to build pastoral environments with precision bite management, and how to create sward structures to influence the temporal and spatial dynamics of animal biting.

Rentabilidade da produção de ovinos de corte em pastagem e em confinamento

Os objetivos neste trabalho foram analisar a viabilidade economica de sistemas de producao de cordeiros e identificar os componentes de maior influencia no custo de producao. O estudo foi realizado em duas etapas. Na etapa 1, realizou-se a comparacao de quatro sistemas de terminacao de cordeiros: 1) desmame aos 60 dias e terminacao em pasto; 2) cordeiro com mae em pasto; 3) cordeiro com mae em pasto e concentrado (1% PC/dia) em creep feeding; e 4) desmame aos 60 dias e confinamento. Na etapa 2, um modulo de 150 ovelhas em 9 ha de pasto cultivado nos sistemas em pastagem e 7 ha no confinamento foi proposto a partir do experimento para avaliacoes economicas, considerando a venda de cordeiro vivo terminado ou abate e venda de carne, alem da venda de matrizes. Foram realizados calculos de custo fixo (depreciacao), variavel (materiais, mao-de-obra, transporte, abate, juros, conservacao, despesas gerais) e total (fixo+variavel), lucratividade e rentabilidade, valor presente liquido, taxa interna de retorno e custo/beneficio. O maior custo total foi observado no confinamento e o menor, no sistema de cordeiro terminado com a mae em pasto. A margem liquida na venda de cordeiros foi negativa em todos os sistemas. A venda de carne apresentou margem liquida negativa apenas para terminacao em confinamento. A taxa interna de retorno para venda de carne foi: 1,4% no desmamado em pasto; 4,3% no de cordeiro com mae em pasto; 2,1% no creep feeding; e -2,3% no confinamento. Os componentes do custo operacional total com maior influencia sobre o custo de producao nos sistemas a pasto, em ordem decrescente, foram mao-de-obra e alimentacao; no confinamento, foram alimentacao e mao-de-obra. A venda da carne apresentou lucratividade maior que a venda de cordeiro vivo, com maior valor no sistema sem desmame terminado na pastagem.

Ryegrass pasture characteristics and lamb productivity in grazing

The objective of this study was to evaluate the ryegrass pasture production, forage quality and animal productivity in three sheep production systems: lambs weaned at 40 days of age and finished in ryegrass (Lolium multiflorum Lam.) until slaughter; lambs kept with their dams in the same pasture until slaughter; same treatment, but the lambs were supplemented in 1% of live weight with concentrate in creep feeding. The grazing method was continuous variable stocking, in order to maintain 1,000 kg of leaf dry matter per hectare. The mean forage production was 3,236.6 kg DM/ha, the leaf lamina production was 1,008.7 kg DM/ha and the pasture daily growth rate was 58.38 kg/ha. With weaned lambs, the mean height of pasture (20.95 cm) was higher when compared to others. The inflorescence production in pastures for weaned lambs (61.7 kg/ha) was higher when compared to other systems. Weaned lambs presented higher animal stocking rate 929.7 kg BW/ha, considering only lambs without supplementation (259.9 kgBW/ha) or with creep feeding (254.3 kgBW/ha). The forage quality was not different between systems. The pasture structure changed due to the higher selectivity of lambs without dams in pasture. The productivity of the weaning system was reduced due to lower individual performance of lambs; therefore, this system should not be recommended for sheep breeders.

Aspectos metodológicos do comportamento ingestivo de bovinos em pastejo

It was evaluated grazing times of heifers in natural pasture, obtained by visual assessment in 5-minute intervals. By using the original data, it was calculated observation intervals of 10, 15 and 20 minutes. It was used four crossbreed Angus × Nellore heifers, with average weight of 249 ± 6 kg BW. The completely randomized block design was used with four treatments (forage allowance of 4, 8, 12 and 16 kg DM/100 kg BW) and two replicates, and type of soil was the blocking factor. The grazing method was continuous stocking with variable stocking rate. Grazing time, ruminating time and time of other activities did not differ among scales tested, therefore, they can be observed at every 20 minutes, but the number and duration of meals and its intervals presented variations according to observation scale. Only the observation scale of 5 minutes allowed the detection of daily modifications which compose meal dynamics upon the ingestive behavior of grazing animals. Estimates proved overestimation of 20 minutes in meal duration when observed at every 10 minutes in relation to the observation at every 5 minutes.

Composição tecidual da carcaça e perfil de ácidos graxos da carne de cordeiros terminados a pasto ou em confinamento

The objective of this study was to evaluate tissue composition of loin and leg and fatty acids profile of the meat of lambs in four finishing systems: (1) lambs weaned around 40 days of age and kept in ryegrass pastures until slaughter; (2) lambs kept with their dams in the same pasture until slaughter; (3) same treatment of (2), but daily supplemented with 1% of the body weight in creep feeding; (4) lambs weaned at 40 days of age and confined, fed corn silage and concentrate ad libitum. It was used a complete random experimental design with four finishing systems and three replications. Lambs were slaughtered at body weight of 32 kg. Loins and right legs were used for determining tissue composition and the left loins were used for analyzing fatty acid profile. Length and maximal deep of the muscle, minimal and maximal thickness of backfat and loin eye area were measured on the left legs. Pasture finished weaned lambs showed lower fat deposition on the carcass and leg muscularity index. Muscle development and fat deposition on finished weaned lamb with or without supplementation were similar to the ones observed on feedlot finished weaned lambs. Lambs in creep feeding showed more fatty acids in the meat than pasture weaned lambs. Finishing systems influence tissue composition but they do not affect fatty acid profile in meat for human consumption.

Faecal index to estimate intake and digestibility in grazing sheep

SUMMARY The current research was carried out to evaluate the use of crude protein and fibre components in faeces for estimating intake and digestibility in sheep fed with pearl millet (Pennisetum americanum (L.) Leeke). The equations were developed from four trials in metabolism cages with 16 sheep in each trial. Eachanimal received a different quantityof millet leaves in the diet: 0·015, 0·020 and 0·025 dry matter (DM) as a proportion of liveweight (LW) and ad libitum with at least 0·2 of daily feed refusals. Organic matter intake (OMI, g/day) was measured, through the difference between offer and refusals; total faeces were collected for 5 days, which was used to determine faecal crude protein (CPf, g/day and g/kg of organic matter (OM)), faecal neutral detergent fibre (NDFf, g/day and g/kg OM), faecal acid detergent fibre (ADFf, g/day and g/kg OM) and OM digestibility (OMD). Linear regression equations were calculated to determine the relationship between OMI and CPf (P<0·001, R 2 =0·90, relative prediction error (RPE=14·02%). A multiple linear equation was generated for OMI including CPf and NDFf (P<0·001, R 2 =0·94; RPE=9·25%). Hyperbolic (single and multiple) and exponential models were tested to estimate OMD, where the hyperbolic multiple model including CPf and NDFf showed lower RPE (3·90%). These equationsforestimatingOMIandOMDwereevaluatedonsheepgrazingP.americanumfertilized withincreasing levels of nitrogen (N) (50, 100, 200 and 400 kg N/ha), comparing measured and estimated OMI. The intake estimated by multiple regression (CP and NDFf) showed a higher R 2 (0·98) and lower RPE (5·25%) than the simple (CPf only) linear equation (R 2 =0·94; RPE=20·45%). The results demonstrated the feasibility of using the faecal index generated in metabolism cages for estimating intake and digestibility in sheep grazing P. americanum.

Urinary creatinine as a nutritional and urinary volume marker in sheep fed with tropical or temperate forages

To test the accuracy of creatinine as a marker for estimating urinary volume and its use as a nutritional index, the possible interference of forage intake and forage quality over creatinine excretion was evaluated. For this, sheep were fed different levels of pearl millet (Pennisetum americanum(L) Leeke) or Italian ryegrass (Lolium multiflorum Lam). The experiment consisted of a compilation of digestibility trials (n=6) with pearl millet or Italian ryegrass in completely randomized designs with four replications and four forage levels: 1.5, 2.0, 2.5% (kg dry matter (DM)/ 100 kg of live weight (LW)). The trials were repeated at different periods to evaluate how stable the average metabolic excretion of creatinine is. In each trial, total urine collection was performed individually during a period of 24 hours for five consecutive days and subsequently analyzed by colorimetry for creatinine and purine derivatives. The creatinine excretion was not affected (P>0.05) by forage offer or forage type, but there were period effects (P=0.0001). The average creatinine excretion for both forages was 0.21mmol/kg PV0,75. Linear regressions between the purine derivatives:creatinine index with total excretion of purine derivatives were detected for pearl millet (P<0.0001, R2= 0.64) and Italian ryegrass (P=0.02, R2=0.20). These results demonstrate that creatinine excretion is independent of the type and availability of forage and can be a marker for urinary volume prediction and nutritional measures under grazing systems.

Relação entre o escore de comportamento materno e as características fisiológicas de ovelhas

The objective of this study to assess the relationship between ewe maternal behavior score and physiological parameters related to their temperament. During lambing, 258 Corriedale and 50 Polwarth ewes were evaluated. They were raised on native pasture in the southwest region of Rio Grande do Sul State, Brazil. The effects of farm, age, type of lambing, maternal behavior scores and body condition score before lambing and during the weaning were evaluated in relation to heart rate, respiratory rate and body temperature of animals at weaning. In the first 24 hours after lambing, the maternal behavior score was assigned to the ewe as the distance from its lamb: 1) >10 meters and does not return to the lamb; 2) >10 meters from the lamb, but returns; 3) five to 10 meters; 4) between one and five meters; 5) less than one meter; 6) maintains physical contact. Ewes with maternal behavior score of 3. Sheep raised on the farm in Bage municipality had higher heart and respiratory rates. Ewes with a body condition score before lambing of <2.0 had lower levels of heart and respiratory rates and body temperatures. On the other hand, ewes with body condition score at weaning of <2.0 had the highest values of heart and respiratory rates, and the lowest body temperatures. The lack of association between the physiological parameters measured at weaning and maternal behavior does not allow for the recommendation of its use to estimate postpartum reactivity and maternal ability of ewes.

Composição tecidual e perfil de ácidos graxos do lombo de cordeiros terminados em pasto com níveis de suplementação concentrada

Meat composition is an important aspect on evaluation of sensory and nutritional quality of the product. This work had the objective of evaluating tissue composition and fatty acids profile of loin lambs weaned at 42 days of mean age and finished on ryegrass pasture with levels (0%; 1% and 2% of BW; ad libitum) of daily concentrate supplementation. The experiment was allocated in randomized blocks design with three replications. Lambs were slaughtered when individual live weight reached 32kg. Tissue composition was determined in right loin and left loin was used for fatty acids profile analyses. Analysis of variance and regression were performed by using SAS (2001). The concentrate supplementation of lambs finished on pasture did not affect (P>0.05) muscle and bone development, however, promoted linear increase on intermuscular and total fat. Levels of supplementation did not affect (P>0.05) the amount and percentage of each fatty acids in lambs meat. The concentrate supplementation of weaned lambs finished on ryegrass pastures increased fat covering on carcass without changing meat quality to human feeding considering fatty acids profile.