Viviane da Silva Hampel

The objective of this work was to evaluate the performance and ingestive behavior of singleton and twin lambs after weaning under different feeding systems on tropical pasture. Studies were carried out over three years with castrated and weaned males of Texel x Corriedale lambs. In the first year, the treatments were: grass; grass and supplementation with concentrate (1.5% or 2.5% of live weight); grass and controlled legume grazing. In the second and third years, the treatments were: either grass or legume; mixed, this is, contiguous area of both grass and legume. On tropical pasture system, twin lambs fed with high levels of concentrate can gain more live weight than singletons, showing a compensatory growth and reaching the singletons live weight. Sheep litter size does not affect weaned lambs’ grazing behaviour under different feeding systems on tropical grassland. The use of concentrate supplementation changes lambs’ ingestive behavior by reducing grazing time and increasing idling time. Pigeon pea, as a monoculture or associated with grass, can be an important source of nutrients for lambs; however, it is not sufficient to ensure the same performance of twin and singleton lambs.

O objetivo do estudo foi avaliar o desempenho de novilhas de corte do desmame ao fim do período reprodutivo aos 13/15 meses de idade submetidas a três sistemas alimentares nos meses de inverno após o desmame: pastagem de aveia preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.); pastagem de aveia preta e azevém mais suplementação com 1% do peso corporal com farelo de trigo (FT); e pastagem de aveia preta e azevém mais suplementação de 1% de peso corporal com farelo de trigo e 200 ml/cabeça/dia de glicerina bruta (FTG). As suplementações não afetaram a taxa de prenhez das novilhas púberes anteriormente ao período reprodutivo, mas determinaram mais novilhas púberes e maior concepção nos primeiros 21 dias do acasalamento. Novilhas prenhes, independentes dos tratamentos, possuem melhores características fenotípicas de conformação, precocidade, musculatura e tamanho já ao desmame, maior ganho diário médio e condição corporal ao início e fim dos sistemas alimentares e início da temporada reprodutiva, o que permite uma seleção prévia, a idades menores, das bezerras a serem postas em sistemas alimentares para prenhez aos 13/15 meses de idade. Rebanhos com prenhez estabilizada aos dois anos de idade necessitam de seleção para maior precocidade sexual e prenhez aos 13/15 meses de idade, podendo o peso ao desmame ser um bom preditor.

Objetivou-se avaliar o desempenho de cordeiras em pastagem de azevém (Lolium multiflorum Lam.), relacionando a estrutura da pastagem em três estádios fenológicos: vegetativo, pré-florescimento e florescimento, com diferentes suplementos. Os tratamentos incluíram pastejo exclusivo, pastejo com grão de milho moído, farelo de arroz integral (FAI) ou grão de arroz. O método de pastejo foi intermitente, com intervalo de 187 graus-dia. Os suplementos eram oferecidos individualmente por uma hora, e as sobras recolhidas para cálculo de ingestão. O ganho médio diário (GMD) das cordeiras foi calculado pela diferença de peso entre o início e o final do período, dividido pelo número de dias entre as pesagens. O delineamento foi inteiramente casualizado com parcelas subdivididas: sistemas alimentares nas parcelas principais e estádios fenológicos nas subparcelas. Os resultados foram analisados por teste de normalidade e variância, com comparações pelo teste Tukey, usando o programa SAS 9.2. O consumo de suplemento das cordeiras que receberam grão de milho não diferiu das que ingeriram o grão de arroz, mas foi 32,14% superior àquelas que receberam FAI. Cordeiras que receberam grão de milho como suplemento apresentaram maior GMD (0,238 kg) e maior eficiência na conversão de pasto, enquanto as que permaneceram exclusivamente em pastagem tiveram o menor GMD (0,167 kg). O GMD das cordeiras que receberam arroz ou FAI não diferiu significativamente dos outros tratamentos. O consumo de suplemento foi maior para cordeiras que receberam grão de milho em comparação às que receberam FAI. Conclui-se que a suplementação com grão de milho proporciona maior GMD em ovinos em pastagem de azevém.

Large areas of tropical grass pastures are not grazed by lambs because of the difficulties in managing high growth rate swards with high selective animals. The objective of this study was to evaluate the physical and biochemical characteristics of tropical pastures offered to lambs in continuous grazing. An upright grass and a shrub legume were set out in three pasture types and grazed by lambs: (1) aruana grass monoculture (AG—Panicum maximum Jacq. cv. IZ‐5), (2) pigeon pea monoculture (PP—Cajanus cajan [L.] Millsp. cv. Anão) and (3) contiguous swards (CS), half of the paddock with AG (CSAG) and half with PP (CSPP). The pastures were evaluated for structural characteristics, production, nutritional composition and antioxidant concentrations in four periods over 92 days of continuous grazing by lambs. Hand plucking samples, similar to animal diet, were collected for chemical analysis. Regarding height, the PP legume monoculture after 42 days of grazing had uncontrollable growth by the lambs, reaching 1.2 m in height. This same legume but as a CS beside AG (CSPP) was maintained at a lower and similar height throughout the experimental periods. In general, the leaf:stem ratio of the different pastures decreased over the experimental periods from 0.7 to 0.2. In most periods, the CS showed intermediary nutritional quality compared to AG and PP. The alpha‐tocopherol content was similar among swards, with an average of 137.2 ± 13.67 mg/kg of green matter (p > .05). Pigeon pea showed the highest levels of total tannin and condensed tannin at 63 and 92 days (p < .05). The use of tropical grass together with a legume provides a better physical structure of the pigeon pea for grazing lambs than when monoculture of this species.

Tropical sward characteristics can alter lamb ingestive behavior. Our study evaluated the ingestive behavior of young lambs in different tropical pastures to identify which variables interfere in their grazing activity. Two years of study were carried out with 54 weaned lambs distributed in three different swards: 1) monoculture of a upright grass, guinea grass ( Panicum maximum ; GG); 2) monoculture of a shrubby legume pigeon pea ( Cajanus cajan ; PP) and 3) contiguous areas with half the paddock with GG and half with PP (GP). The experiment was set out in a randomized complete block design. Lamb ingestive behavior was observed from sunrise to sunset with records every 5 minutes. To identify the main variables that affected with the lamb grazing activity, a multivariate analysis of the Decision Tree was performed. Our results showed that there was no difference in the ingestive behavior parameters of young lambs in different swards ( P > 0.05). There was interaction among the swards and the experimental periods for the variables idleness time and biting rate ( P ≤ 0.05). Grazing time of the animals increased 40% with experimental period progression. The Decision Tree identified leaf:stem ratio as the variable that most influenced lamb grazing time in GG and GP swards while in the PP sward grazing time was directly related to the pasture height. The behavior of young lambs on tropical pasture is variable as there is a change in the behavioral response over time. In addition, the grazing time of these animals can be estimated by means of variables related to pasture structural characteristics (leaf:stem ratio and height) together with chemical variables.

Tropical pastures can be important natural sources of antioxidant compounds and may impact production and quality of animal protein with repercussions on human health. The objective of this study w...

The objective of the present study was to evaluate, through a meta-analysis, the effects of feeding systems and tocopherol levels found in the diet of lambs on qualitative characteristics of their meat. A search of the computerised literature in Science Direct databases, PubMed, Scopus, and SciELO virtual library was carried out to select works that evaluated the quality of lamb meat. As a first requirement for inclusion in the meta-analysis, articles were selected with the keywords “tocopherol”, “meat”, and “lamb”. The variables extracted from the articles were classified according to the type of feeding system and tocopherol level in the diet of lambs. Production systems alter the qualitative characteristics of meat. Lambs raised exclusively on pasture present a higher tocopherol concentration in their meat, a lower omega 6:omega 3 ratio, a lower omega 6 concentration, and a higher conjugated linoleic acid concentration. Regardless of the dietary systems, when we classify the tocopherol levels of lamb diet, the tocopherol concentration and fatty acid level are altered by tocopherol levels in the diet. The lower tocopherol level in the diet results in meat with lower tocopherol concentration and with greater propensity to lipid oxidation.

We evaluated the grazing behavior of heifers, at two phenological stages (vegetative and reproductive) of ryegrass (Lolium multiflorum Lam.), in four times of the day (early morning, morning, evening, and night), with heifers either exclusively grazing or with oat, or corn grain, supplementation. The experimental design was completely randomized, in sub-subdivided plot arrangement, in which the main plots were the feeding systems, the sub-plots were the phenological stages and the sub-sub-plots were the times of day. We assessed ingestion behavior along 24 hours through visual observation, on four evaluation dates, two during the vegetative stage and two during the reproductive stage, studying time spent on grazing, rumination, or other activities, as well as number and duration of, and interval between meals. Supplemented heifers remained less time at a feeding station, performed fewer bites daily and, during the reproductive stage of the ryegrass, spent more time in other activities. Grazing time of supplemented heifers was shorter in the morning and at night, and the duration of their meals was shorter at night. A change occurred in the pattern of time use when heifers received supplement, and when the structural and qualitative characteristics of the pasture changed during the vegetative and reproductive phenological stages of ryegrass.