Marcelo Abreu da Silva

Avaliação da qualidade do leite na bacia leiteira de Pelotas, RS. Efeito dos meses do ano

RESUMO - Os efeitos dos meses do ano sobre a composicao e producao do leite foram avaliados atraves do acompanhamento de 10 unidades produtoras de leite, divididas em tres sistemas de producao classificados como especializado (ES), semi-especializado (SE) e nao-especializ ado (NE), durante 11 meses do ano. Foram coletadas amostras de leite diretamente dos tanques refrigeradores para determinacao das caracteristicas fisico-quimicas e contagem de celulas somaticas (CCS). Quantificaram-se a incidencia de mastite e a producao media de leite (litros/vaca/dia) e coletaram-se amostras de agua utilizada para consumo e limpeza, de pastagem, concentrado e silagem. O delineamento adotado foi o completamente casualizado, em arranjo fatorial desbalanceado, considerando como fatores os meses do ano, os sistemas de producao e a sua interacao. Nao foi encontrada variacao significativa entre os meses estudados para producao de leite, valores de crioscopia, porcentagens de gordura, extrato seco, nitrogenio nao-proteico, CCS, composicao quimica, contagem de coliformes da agua e composicao bromatologica do concentrado. Os maiores valores de proteina verdadeira do leite foram observados em outubro e novembro, enquanto os maiores de caseina, em outubro, novembro, marco e abril. O extrato seco desengordurado foi superior em dezembro e a acidez variou juntamente com a incidencia de mastite, sendo superior nos meses de novembro e maio. Em relacao a proteina bruta, ocorreu interacao entre meses e sistemas. Foram observadas correlacoes negativas entre producao de leite e gordura, mastite e CCS, e correlacao positiva entre producao de leite e lactose. O leite produzido nos diversos meses do ano diferiu, principalmente, quanto a incidencia de mastite, fracao proteica, extrato seco desengordurado e acidez. A qualidade da agua nao se modificou expressivamente nos meses em que foi amostrada e se apresentou dentro dos limites considerados aceitaveis.

Comportamento de ovinos em gestacao e lactacao sob pastejo em diferentes estadios fenologicos de azevem anual

This work was carried out at the field to evaluate the grazing sheep behavior conducted in annual ryegrass (Lolium multiflorum Lam.) on vegetative, pre-flowering and flowering stages. Ewes at the end of pregnancy and at the beginning of lactation maintained in a 1.3 ha paddock were evaluated in terms of grazing time, bite rate, bite size, leaf:stem ratio of ingested pasture estimated by hand-plucking method. Daily grazing time/h of 9.65, 10.97 and 10.68, bite rates/min of 52.65, 51.93 and 40.63 and the bite weight g/bite of 0.064, 0.055 and 0.048 were observed for vegetative (VS), pre-flowering (PS) and flowering stages (FE), respectively. This behavior resulted in forage intake rates of 4.48%, 3.91% and 2.72% of body weight on VS, PS an FS, respectively These evolutions were accompanied by reduction of the leaf:stem ratio of available forage (4.36:1, 1.11:1 and 0.17:1) which were in accordance to the qualitative limitation that occurs in the flowering stage. These data showed that until pre-flowering stage, the strategies desenvolved by the animals allowed an adequate intake forage, while that in the flowering stage the low quality pasture determinated a decrease intake, being this considerate insufficient to attend nutritional necessities of lactating ewes and respective lambs.

Sheep behavior at the pregnancy and at the lactation grazing on different phenological stages of annual ryegrass

This work was carried out at the field to evaluate the grazing sheep behavior conducted in annual ryegrass (Lolium multiflorum Lam.) on vegetative, pre-flowering and flowering stages. Ewes at the end of pregnancy and at the beginning of lactation maintained in a 1.3 ha paddock were evaluated in terms of grazing time, bite rate, bite size, leaf:stem ratio of ingested pasture estimated by hand-plucking method. Daily grazing time/h of 9.65, 10.97 and 10.68, bite rates/min of 52.65, 51.93 and 40.63 [...]

Efeito de diferentes sistemas de pastejo sobre o desempenho de suínos mantidos em pastagem de trevo-branco (Trifolium repens L.)

This trial was carried out to determine the effect of continuous, alternated or rotational grazing systems on the performance of pigs (feed intake, weight gain, feed conversion and backfat thickness), in the growing and finishing phases, as well as the forage availability and chemical composition of a white clover pasture (Trifolium repens L.). Thirty-six castrated pigs were allotted to a randomized complete-block experimental design with three treatments and three replications. Twelve feedlot pigs were kept on a rearing system. No significant differences were found between grazing systems on parameters of animal performance and forage on offer. However, significant differences were observed on the pasture chemical composition between the grazing systems studied. Pigs reared on white clover pasture consumed from 13.41 to 15.92% less feed and showed smaller backfat thickness and weight gain than pigs reared in the confined system. No significant differences on feed conversion between feedlot pigs and pigs under pasture conditions were observed.

Composição do leite de vacas Holandesas em pastejo de azevém com a utilização do trevo branco como fonte proteica

Was evaluated the composition of milk from animals grazing annual ryegrass (Lolium multiflorum Lam.) fed with white clover (Trifolium repens L.), as a replacement for the protein component of the ration (soybean meal), in percentages of protein, lactose, total solids and somatic cell counts. Were used two groups with eight Holstein cows, grouped by production, lactation period and body weight, in a randomized block design. One group received 3kg of energetic supplement subtracted of soybean meal daily and had access to the white clover pasture for approximately 2.5 hours (TB); the other received the same supplement, added of a quantity of protein equivalent to daily intake in previous treatment via white clover, in the form of soybean meal (FS). Significant differences were observed for protein and lactose content, with the highest values found for protein on TB (3.02%) and lactose on FS (4.64%). For the other variables there was no difference, with values from 10.40 and 10.39% of total solids and 182.88 and 153.53 (x1000) somatic cells on TB and FS respectively, showing that the use of this alternative source of protein was efficient.

Milk quality of Jersey cows kept on winter pasture supplemented or not with concentrate

Este trabalho foi realizado com o objetivo de avaliar o efeito do uso de suplementacao em pastagem cultivada constituida por Avena strigosa (aveia-preta), Lolium multiflorum (azevem-anual) e Vicia sativa L. (ervilhaca) sobre a composicao e a contagem de celulas somaticas (CCS) do leite de vacas Jersey. Foram utilizadas oito vacas da raca Jersey, distribuidas ao acaso, apos estratificacao por producao de leite, periodo de lactacao e peso corporal, em dois grupos homogeneos (um com suplementacao e outro apenas em pastagem), em delineamento experimental completamente casualizado. Os dois grupos foram mantidos na pastagem por aproximadamente 7 horas por dia em um sistema de pastejo rotativo em faixas, com periodo de ocupacao de um dia. O grupo sob suplementacao recebeu diariamente 8 kg de suplemento constituido de farelo de soja, casca de soja, calcario calcitico e sal mineral. Os resultados evidenciaram diferencas significativas entre os dois grupos, uma vez que os percentuais de solidos totais, proteina e gordura do leite foram maiores nas vacas sob suplementacao. O percentual de lactose nao foi influenciado pelo consumo de suplemento. A contagem de celulas somaticas, embora com diferenca estatistica menor para o grupo em pastagem, apresentou pequena oscilacao numerica entre os grupos, a qual nao pode ser considerada efeito da suplementacao. O fornecimento de suplemento a vacas Jersey em lactacao promove aumento do percentual de solidos totais do leite, uma vez que eleva suas concentracoes de gordura e proteina.

Tipologia de sistemas de produção bovina com ênfase na ocorrência de ectoparasitoses

This study was carried out to identify, by using diagnostic research procedures, characteristics of production systems related to the occurrence of ectoparasites. Data of semi-structuralized interviews in 62 farms were analyzed by multivariate statistical procedures. Greater importance was observed for the property area, pasture management and the frequency of the property visits to his establishment. The used method, the season and the frequency of the applications of tick pesticides differed among the control types of ectoparasites. The results reaffirmed the importance of the research diagnostic procedures as tool of identification of economic and technician problems of production systems and representation of its diversity, indispensable subsidies for the development of more coherent experimental works with the productive reality of the state.

Comportamento de suínos submetidos a diferentes sistemas de pastejo em pastagem de trevo-branco

This work aimed to study the behaviour of pigs submitted to different grazing systems (continuous, alternated or rotational) in white-clover (Trifolium repens L.) pasture and fed ad libitum. Thirty-six finishing pigs, castrated males, averaging 80 kg were used. The behaviour activities (feeding, grazing, drinking, standing, laying, sitting, walking, urinating, defecating, playing, itching, rooting, and digging) were recorded by visual observations during three consecutive days, from 7:00 a.m. to 6:00 p.m. The experiment was analyzed as a complete randomized blocks, with three treatments and three replicates. The observations were made every 10 minutes and the number of animals and the respective activities on each grazing system were recorded. Lying, drinking, feed intake, grazing and walking were the activities that showed higher frequencies, regardless of the grazing system. Pigs on alternated grazing system showed higher frequency feed intake activity than pigs on continuous or rotational grazing systems. During the first day of observation, pigs on continuous or rotational grazing systems showed higher frequency grazing activity than pigs on alternated system. The pigs on continuous and rotational grazing systems showed similar behaviour activities. The behaviour of growing pigs was affected by the grazing system.

Interação comportamento de pastejo ´ dinâmica de tipos funcionais em pastagem natural na depressão central do Rio Grande do Sul

This study aimed to describe the feeding and spatial behavior of beef heifers under rotational stocking, in response to the dynamics of the morphological functional types (TFs) in natural grassland. Stocking rate was adjusted to keep an average of 12% (12 kg DM/100 kg BW) of forage allowance. Animal activity was registered from 12 to 27 February 2003 using the Ethosys automatic device. Thirty permanent field sampling units comprised by five adjacent 0.20 x 0.20 m squares were used to determine pasture attributes. Results showed the existence of an optimum subset of two attributes to describe pasture plant community: the aerial and the lignified (woody) forage biomasses, which defined eight morphological functional types that had a 0.43 congruency value with the variable degree-day. The evolution of grazing activity showed that grazing time increased as the frequency of preferred functional types decreased. Thus, the morphological characterization of functional type-based attribute definition can bring more contributions for the interactive response between the vegetation and the animal behavior than the one realized using only the taxonomic identification. Therefore, in a simultaneous action, as the vegetation change, the animals modulate the behavior adjusting their rhythm of activity in time and space, determining, in a continuous process, differential impacts in the vegetation, which evolves with time.

Comportamento ingestivo de vacas leiteiras em pastagem de azevém alimentadas com diferentes fontes proteicas

The effect of the replacement of soybean meal in the ration with controlled grazing of white clover (Trifolium repens L.) on the ingestive behavior of cows of the holstein breed grazing on annual ryegrass (Lolium multiflorum Lam.) was studied. Two groups of animals with an average of 20 cows grouped by production, lactation period and body weight were used in a randomized block experimental design. One group received 3kg from energy supplement daily and had controlled access to the white clover pasture for approximately 2.5 hours (TB); the other received the same supplement, added of a quantity of protein equivalent to daily intake in previous treatment via white clover, in the form of soybean meal (FS). For behavior assessment the observation and recording of the rhythm of activity of the animals, during the grazing period in ryegrass for two consecutive days, fortnightly was done. The longest grazing time in minutes (min), 212.00 versus 194.24min day-1, and bite frequency (bite), 67.78 versus 64.09 bite min-1, between the animals from treatment FS, when compared to TB was observed. There was no difference in the intake of ryegrass between the treatments, with values of 3.65 and 4.11kg cow-1 day-1 of dry matter for TB and FS, respectively, suggesting adequate adaptation of the animals in the two situations studied.