Lower Daily Weight Gain Research Articles

The effect of the quality of dietary lignocellulose on digestion, zootechnical performance and health of the growing rabbit

AbstractThe aim of this study was to evaluate the performance and digestive response of the growing rabbit according to a change in the nature of the lignocellulose (ADF), without a change in the ADF level. Three diets with a linearly decreasing lignin/cellulose ratio (ADL/cellulose = 0·8; 0·4; 0·2; respectively LC8, LC4, LC2) were given to a total of 162 rabbits per diet, from weaning till slaughter weight. A reduction of the ADL/cellulose ratio led to a lower food intake (LC8 v LC2: -11%), associated with a lower daily weight gain (-6% for LC2). Mortality and morbidity rate was significantly greater (+50%) for LC2 and LC4 diets compared with the LC8. Thus, the health risk index (morbidity + mortality) increased by 20 units for LC4 and LC2 compared with LC8 diet. In parallel, rate of passage was slower (mean retention time 4·5 h greater,P= 0045) with LC4 and LC2 diets. Dry-matter digestibility was slightly affected, whereas protein digestion was favoured with low ADL/cellulose ratio. It is recommended that a minimum lignin supply (about 6 g/day) is adopted as well as a minimum dietary lignocellulose to ensure growth performance and health of the growing rabbit.

One or Two Feeders for Groups of 16 Growing–Finishing Pigs: Effects on Health and Production

Over a 3-year period, seven batches of growing-finishing pigs in groups of 16 pigs (total 672 pigs) were fed using one or two singlespace feeders. The pigs with access to two feeders had a significantly lower number of skin lesions (P<0.0001) and higher daily weight gain than did the pigs with access to one feeder (863 vs. 837 g day- 1 , P<0.05). The within-pen variation in daily weight gain was higher in the pens with one feeder than in the pens with two feeders (SD 139 vs. 106g day- 1 , P<0.0001). The pigs with access to two feeders consumed more feed during the period when they were allowed to eat ad libitum , in comparison to the pigs with access to one feeder (2.07 vs. 1.97 kg day- 1 , P<0.05). The feed conversion ratio of the pigs did not differ between the two treatments. No differences in carcass meat percentage, health or number of remarks at slaughter were detected. A comparison was made between using computerized IVOG® feeders, with individual recording of feed intake, and conventional feeders. The feed conversion ratio was poorer for the pigs fed with the IVOG-feeders than for those fed with conventional feeders. The automatic recordings from the IVOG-system showed that there had been a higher daily feed intake during the ad libitum period. During the restricted period the pigs had a lower daily weight gain than with the conventional feeders.

Effect of Feeding Environment on Performance, Injuries and Behaviour in Growing-finishing Pigs: Group-Based Studies

Ten batches of pigs (608 pigs) were used in this investigation (live weight interval 20-120 kg). Four different feeding systems were tested: one dry feeder, four dry feeders, trough feeding or one wet/dry feeder per pen of 16 pigs, respectively. The one dry feeder treatment led to an increase in skin injuries, a more spread feed intake pattern, an increased variation in carcass meat percentage and an increased variation in daily weight gain (DWG) when the pigs were restrictively fed, compared with observations for the pigs in the four dry feeders treatment. The effect of a reduced number of feeding places was most pronounced when the pigs were fed restrictively. Besides the possible negative financial effects for pig producers, these findings indicated that competition for feed impaired the well-being of the pigs. Pigs fed in a trough had a lower DWG and higher feed conversion ratio than did those fed using four dry feeders, probably due to feed spillage and the different feed intake pattern. Giving pigs the possibility of adding water to the feed increased the daily feed intake when feeding ad libitum, resulting in a higher DWG. It also reduced the negative effects of competition on performance, but not the negative effects on skin injuries.

Coal tits, Parus ater, lose weight in response to chases by predators

Theoretical models predict that birds should decrease their body mass in response to increased predation risk because lighter birds take off faster and are more manoeuvrable. We studied the effect of predation risk by chasing coal tits in large outdoor aviaries thus simulating an attempt to capture them. With this increase in predation risk, both perceived and actual, coal tits lost significantly more weight than in a control situation when they were not pursued. This pattern was attributable to a smaller gain in weight only during the day; nocturnal weight did not change in relation to diurnal predation risk. The lower daily weight gain was not consistent with predictions from models of interrupted foraging, but was consistent with predictions from risk adjustment models. Moreover, there was no difference in weight gain over 2-h periods that included a 1-h fast and those in which feeding was ad libitum, suggesting that coal tits could easily regain their body mass after a predator had interrupted their feeding. Our results therefore suggest that pursuit by predators leads to a decrease in the body mass of small birds.

Effect of the type of diet on muscle characteristics and meat palatability of growing Salers bulls

The effect of the type of diet (hay vs grass silage) on body composition and characteristics and palatability of semitendinosus (ST) and longissimus thoracis (LT) muscles of 16 month old Salers bulls fed at the same energy levels were studied. Animals fed hay had a lower daily weight gain and carcass weight and were leaner. There were no significant differences in the proportions of fibre types in the ST or LT due to diet. ST muscle of hay fed animals had a lower oxidative metabolism, but contained similar amounts of total and type I collagen and greater amounts, and proportions of soluble collagen and of type III collagen, than those of animals fed grass silage. ST muscles of hay-fed animals were more tender than those of silage-fed animals.

Ecopatologia da diarréia pós-desmame em granjas de suínos da região norte do Paraná, Brasil

Durante o ano de 1994, foram avaliadas 18 granjas suinícolas da região norte do Paraná, conduzidas sob sistema confinado, com o objetivo de identificar os fatores de risco mais freqüentes na fase de creche. Em cada granja, foram acompanhados no mínimo 30 leitões do desmame até 21 dias após. Nesse período, foram observadas 3 variáveis objetivas (taxa de mortalidade, ocorrência de diarréia e ganho de peso médio diário) e 9 variáveis explicativas (ganho de peso médio diário, 21 dias após o desmame, energia consumida pela porca durante o ciclo reprodutivo, lotação na creche, número de leitões por baia, percentual de espirros, percentual de tosse, comprimento do comedouro por leitões, consumo de ração/dia/matriz na lactação e vazio sanitário da creche). As variáveis foram analisadas utilizando o programa estatístico desenvolvido pelo CNPSA/EMBRAPA. A variável de risco mais prevalente no pós-desmame foi a ausência de vazio sanitário (observado em 83,34% das granjas), seguida com menor freqüência (presentes entre 40 a 70% das granjas) pelos fatores: elevado percentual de leitões com tosse, alta lotação ou densidade da creche, elevado número de leitões por baia, baixo consumo de energia digestiva por matriz, por ciclo reprodutivo e baixo ganho de peso médio diário, 21 dias após o desmame. As demais variáveis ocorreram em menor freqüência, dentro de níveis inferiores a 30%. A presença da diarréia foi definida como elevada em 50% das propriedades. A taxa de mortalidade foi 2,97% e o ganho médio diário de peso foi 249g. No mapa dos fatores de risco, as granjas localizaram-se predominantemente na região intermediária, indicando a existência de vários fatores de risco na maioria dos rebanhos estudados.

Two avian H10 influenza A virus strains with different pathogenicity for mink (Mustela vison).

We compared two strains of avian influenza A viruses of subtype H10 by exposing mink to aerosols of A/mink/Sweden/3,900/84 (H10N4) naturally pathogenic for mink, or A/chicken/Germany/N/49, (H10N7). Lesions in the respiratory tract during the first week after infection were studied and described. Both virus strains caused inflammatory reactions in the lungs and antibody production in exposed mink but only mink/84 virus was reisolated. The lesions caused by mink/84 virus were more severe with higher area density of pneumonia, lower daily weight gain, and more virus in the tissues detected by immunohistochemistry. The results indicate that mink/84 (H10N4), but not chicken/49 virus (H10N7), established multiple cycle replication in infected cells in the mink.