PubMed Health⌕ Search

Biomedical subjects

D A Little

Publications and source records attributed to D A Little.

8 recordsLinked to original sources
PubMed1991

Influence of partial suckling of crossbred dairy cows on milk offtake and calf growth in the Ethiopian highlands.

The effects of implementing a restricted suckling regime with crossbred dairy cows have been examined in the Ethiopian highlands. Calves were allowed to suckle their dams for two minutes before each milking until weaning and this system was compared with the common practice of rearing by bucket feeding. Restricted suckling significantly increased calf growth rate to weaning, from 0.31 to 0.53 kg/d (P less than 0.01). No differences in calf growth post-weaning occurred, so that the 20 kg difference in liveweight that had been achieved by the restricted suckled calves by the time of weaning persisted until the calves were nine months old, when observations ceased. Total milk offtake was not significantly affected by treatment, although that obtained from the partially-suckled animals over their whole lactation exceeded that from the other treatment by 15%. Partial suckling delayed return to oestrus post partum but this was offset to some degree by fewer services per conception, hence calving interval was not significantly increased. Voluntary feed consumption was similarly unaffected and it is concluded that restricted suckling offers tangible advantages for adoption by smallholders using crossbred cows in dairy production systems.

Animals↗
PubMed1991

Comparison of sesame cake and cottonseed as supplementary sources of protein to weaned N'Dama bull calves in The Gambia.

The potential for increased productivity of N'Dama cattle in response to small supplementary inputs of proteinaceous by-products has been shown to be substantial under village husbandry conditions in The Gambia. Young N'Dama bulls were used to compare sesame cake with cottonseed as sources of supplementary protein during the wet and early dry seasons of 1987. They were fed 0, 40, 80 or 160 g crude protein/day in these forms for four months. Supplementation significantly increased growth rate from 169 g/d in controls to means of 272 and 271 g/d for those given sesame cake and cottonseed respectively; there were no significant differences among the supplemented groups. During the four months of the dry season immediately after supplementation ceased all previously supplemented groups grew significantly more rapidly than the controls (at least P less than 0.05), indicating a substantial carry over effect of the supplements. Over this period the mean gain of the groups previously given sesame cake exceeded that of those that had received cottonseed (217 cf. 158 g/d; P less than 0.01). The economic benefits of these responses were substantial.

Animal Feed↗
PubMed1991

Interaction between physiological status in N'Dama cows and trypanosome infections and its effect on health and productivity of cattle in Gambia.

Data collected for three years on incidence of trypanosome infections, degree of anaemia as assessed by packed red cell volume (PCV) and live weights of four groups of cows of varying physiological status were analysed. The animals were not harbouring trypanosomes during a period of two to three months before exposure to periods of increasing density of tsetse flies (Glossina morsitans submorsitans) while grazing in savannah woodlands. The groups of cows were formed on the following basis: pregnant and lactating (lactating-pregnant) (Group 1, n = 143); pregnant and not lactating (dry-pregnant) (Group 2, n = 69); non-pregnant and lactating (lactating-open) (Group 3, n = 160); non-pregnant and not lactating (dry-open) (Group 4, n = 49). Monthly trypanosome prevalence was highest (17.5%) in the cows with the highest physiological stress (Group 1), followed by Group 3 (11.1%) and Group 2 (10.0%) with the lowest prevalence found in the least stressed cows, Group 4 (1.6%). Average PCV values for dry-pregnant cows (Group 2; 27.0%) and dry-open cows (Group 4; 26.2%), whether infected or not, were higher than those lactating (Group 1; 25.3% and Group 3; 23.6%). A body weight gain of 4.3 kg between the month of October and the following June was recorded for dry-pregnant cows (Group 2) whereas a weight loss of 16 kg occurred in the lactating-pregnant and lactating-open cows (Groups 1 and 3), with more severe losses recorded in infected than uninfected cows. Dry-open cows (Group 4) maintained their weight during the observation period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Husbandry↗
PubMed1979

Phosphorus content of bovine rib: influence of earlier biopsy of the same rib.

Serial sampling of bovine rib is undertaken experimentally to monitor changes in the degree of skeletal mineralisation. The validity of this approach depends on the assumption that the previous sampling of a bone does not influence the composition of a sample obtained subsequently. To test this, the effect of a prior biopsy sampling on phosphorus content of the remaining bone was determined at various times after the initial sampling. A preliminary biopsy sample was taken with a 1.5 cm diameter trephine from the left 12th rib of 40 cattle; experimental samples were taken from the same rib of 10 of the cattle at three, six, nine and 12 months later, for comparison with similar samples taken concurrently from the right 12th rib. The phosphorus content of the second left rib was significantly lower than that of the right (control) rib at the three-month interval, particularly where the sampling site was ventral, rather than dorsal, to the site from which the initial biopsy was obtained. No effects of previous biopsy sampling were observed after six, nine or 12 months.

Animals↗
PubMed1977

Fate of cyst(e)ine synthesized by microbial activity in the ruminant caecum.

Cyst(e)ine synthesized by microorganisms in the caecum of sheep was labelled following the infusion of Na2 35SO4 into the terminal ileum. [35S]Cyst(e)ine activity was detected in the faeces, but not in plasma or wool. Appreciable absorption of 35S, presumably in the form of sulphide, into the circulation occurred, and its presence in saliva was demonstrated. It was concluded that nutritionally negligible quantities of cyst(e)ine are likely to be absorbed from the ovine large intestine.

Animals↗
PubMed1977

The true absorption of cyst(e)ine from the ovine small intestine.

Na234SO4 was infused into the rumen of a sheep fed a dried grass diet. 2. The digesta at the pylorus which contained 35S-labelled cyst(e)ine synthesized by the rumen microflora was collected and mixed with chromium EDTA. This material was infused into the duodenum of 35S free sheep. 3. Ileal digesta was subsequently collected and analysed for cyst(e)ine 35S and Cr. 4. The proportion of the labelled cyst(e)ine truly absorbed from the small intestine was 0-72 +/- 0-004.

Animals↗
PubMed1977

Variation in the phosphorus content of bone samples obtained from the last three ribs of cattle.

Variation in the phosphorus content and specific gravity of bone samples taken from the 11th, 12th and 13th ribs of cattle was examined in relation to the selection of a site for the acquisition of such samples by biopsy, in experiments where changes in skeletal phosphorus storage required to be monitored. The degree of mineralisation of the 11th rib was significantly higher than that of the 12th, which in turn was greater than that of the 13th. It was concluded that valid comparisons may be made between bone samples obtained during an experimental regime, provided they are taken from the same numbered rib; it is recommended that the 13th rib be avoided in such studies.

Animals↗