Weaning Date Research Articles

Influence of weaning age on ileal microflora and fermentation acids in young pigs

Pigs cannulated at the terminal ileum were used to investigate the effect of weaning age on specific intestinal microflora and fermentation acids. In two replicate trials performed 50 days apart, a total of twenty-four 14-day-old nursing pigs from 6 sows were cannulated in the terminal ileum and randomly assigned to either a 21-day (W3) or 28-day (W4) weaning interval. Ileal samples were collected at 20, 23, 27, 30, 34, 37, and 41 days of age. Samples were assayed for total lactobacilli, total and hemolytic coliforms, streptococci, pH, and dry matter. Concentrations of coliforms increased (P < .05) postweaning in both W3 and W4 pigs. Lactobacilli concentrations decreased (P < .05) nearly 1000-fold postweaning in W3 pigs while concentrations decreased (P < .05) 30-fold in W4 pigs postweaning. Percentage of hemolytic coliforms increased (P < .05) with age of pigs on both treatments and continued to increase in W3 pigs through the end of the study. Streptococci concentrations were not affected by treatment. Ileal pH increased (P < .05) postweaning in W3 pigs but remained constant in W4 pigs. Dry matter decreased (P < .05) in both groups postweaning, but lower values were more persistent in W3 pigs. Total volatile fatty acid concentrations decreased (P < .05) in both groups following their respective weaning dates, while total lactic acid concentrations increased (P < .05) in both groups following weaning. Temporary shifts in ileal microflora populations, pH, and dry matter were of greater magnitude and persisted for longer periods in pigs weaned at 21 days compared with pigs weaned at 28 days.

Changes in the Distribution and Activity of Female Harbour Seals During the Breeding Season: Implications for their Lactation Strategy and Mating Patterns

Adult female harbour seals from NE Scotland were radio-tracked to follow changes in their distribution and activity during the breeding season. Seals foraged up to 45 km from haul-out sites, but females with pups restricted their range markedly during the early part of the lactation period. However, foraging trips resumed before the expected weaning date, indicating that female harbour seals do not fast throughout lactation. The duration of the period that females spent inshore with young pups was positively related to female body size, suggesting that the species'small size may demand that they feed to maintain lactation. Foraging in late lactation results in females becoming highly dispersed during the mating period and it is clearly uneconomic for males to monopolize females

The Duration of Lactation in Antechinus-Stuartii (Marsupialia, Dasyuridae)

Free-living Antechinus stuartii at the Monga State Forest showed almost no variation in date of birth, yet weaning took place over a period of three weeks. Males were weaned slightly earlier and at greater weights than females. When daughters were considered, weaning was delayed in years when breeding density was high, and females with ten teats weaned their young later and at slightly lower weights than females with eight teats. The difference between the two teat phenotypes was not simply associated with increased reproductive investment, as successful eight-teated mothers weaned their young earlier than less successful mothers, and there was no relation between weaning success and date of weaning for ten-teated mothers. Age of mother did not influence weaning weight or date, and mothers tended to wean at the same time in each year of their life. These patterns are discussed in relation to recent debate on the detection of life-history trade-offs in free-living populations.

Effects of high inclusion levels of sugar beet pulp in diets for dry sows

The dry sow is well suited to utilise high fibre diets and there are some suggestions that feeding such diets in pregnancy may enhance litter size and subsequent piglet performance. This experiment was designed to investigate the effects on performance of inclusion of a high level of fermentable fibre in the form of unmolassed sugar beet pulp (SBP) in the diet of dry sows.24 gilts and 20 multiparous Landrace x Large White sows were allocated to one of two diets according to weaning or entry date, parity and liveweight. The diets comprised a barley/soya basal diet with either 450 g/kg wheat (diet W) or SBP substituting for this wheat to provide the same quantity of corrected digestible energy (diet B). The two diets were fed at differential levels, to supply the same daily total of corrected digestible energy, from weaning or gilt entry until farrowing. The allocated amount of diet was given in a single daily feeding period to animals confined in individual feeding stalls, and a period of one hour was allowed for the ration to be consumed. After farrowing all animals were fed twice daily on a standard diet, according to a scale related to litter size.

Duration of post‐weaning fast and local dispersion in the southern elephant seal, Mirounga leonina, at Marion Island

Post‐weaning behaviour of southern elephant seals, M. leonina, was studied at Marion Island. Duration of fast in both sexes increased in direct proportion to weight at weaning, while it decreased with weaning date in males. Both sexes appear to fast until they have reached a lower weight ‘threshold’ of around 70% of weaning weight. Local dispersion after the fast was studied by resighting tagged animals at weekly intervals. Only 460 (7.0%) resights out of 6530 involved a move between sites, representing 378 (16.8%) of the 2246 pups that were tagged. Males moved more frequently between tagging sites and covered greater distances than females. Moves between sites are more frequent and distances travelled are greater in December than November. Differences in dispersion patterns between Marion Island and lies Kerguelen may be caused by differences in coastal configuration. Underyearlings spent 105.0±19.6 days at sea before returning for between 10 and 20 days in the autumn. Weaning weight had no effect on likelihood of hauling out in autumn. Movements between sites during the autumn haulout are infrequent and no fidelity to birth site is evident at this stage.

Estimation of the potential demand for a bovine babesiosis and anaplasmosis vaccine in argentina

A survey to estimate the potential demand for a bovine babesiosis and anaplasmosis vaccine was carried out by a postal questionnaire sent to 4407 veterinarians in the north and centre of Argentina. Twenty-three percent of the questionnaires (1047) were answered; 317 (7.2% of the total, 30% of those answered) pointed out the occurrence of the diseases and/or probable demand for the vaccine. The minimum and maximum demands were 407 892 and 982 300 doses for anaplasmosis, and 272 496 and 631 400 doses for babesiosis, respectively. The results presented from here onwards are based on the minimum demand. Sixty-eight and 48% of the anaplasmosis and babesiosis vaccine demand, respectively, came from veterinarians living in the Boophilus microplus-free area, while the remainder came from the tick-infested area, reflecting the fact that many farm owners from the tick-infested area seek professional assistance from veterinarians living in the tick-free area. Most of the demand for both vaccines was aimed at breeding cattle (77.2%), 14.5% at dairy cattle and the rest at studs (8.3%). Veterinarians living in the tick-infested area demanded vaccine for breeding cattle in a higher proportion than veterinarians from the tick-free area, whose demand was greater for dairy cattle. In the tick-free area, the demand for anaplasmosis vaccine was twice that for babesiosis vaccine, whereas in the tick-infested area the demand was equal. This agrees with the fact that the anaplasmosis-stricken area extends beyond the tick-infested region. Sixty percent of the respondents preferred a vaccine frozen in liquid nitrogen, whilst the rest preferred a refrigerated one, the first group accounted for 73% of the total demand. Fifty-six percent of the demand occurred between March and June with the peak in April, which reflects the main weaning date. The elasticity of the demand is discussed in relation to the probable benefits to be accrued by the farmers who make use of it. The annual mortality rates due to both babesiosis and anaplasmosis were estimated at 1.5 and 3.5% in the milk herds of Salta and Tucumán, respectively. In the beef herds of these two provinces, the mortality rate due to both diseases has been estimated at 3.5%. Using these figures and current prices, the systematic application of the vaccine in calves would render a benefit-cost ratio between 4.6 and 9.0, which would warrant its use in the herds of the areas at risk, i.e. in enzootic instability.

Finishing lambs in hill country

A series of farmlet experiments investigated the effects of lambing dates, grazing methods and weaning/disposal dates on lamb production. Ewe and bull performance was also assessed. Laud contour did not significantly affect November-January lamb growth rates. Slight weight differences (-1 kg) in lambs and ewes occurred with changes in weaning date, but later disposal of lambs reduced both ewe and bull weights. Lamb growth rates were best when weaned lambs grazed in front of ewes and bulls in a quick rotation (25 days). Lambing in early August compared with early September, increased lamb weights but reduced lamb number, bull weight gains and ewe liveweights. At current product values earlier lambing reduced returns per ha. Recommendations are made for finishing lambs within mixed livestock systems in hill country. Keywords lamb, grazing management, hill country, agricultural systems, lambing date

The applicable merit of untreated, HCl-treated and partly-hydrolysed straw meal in the feeding regimen of piglets after early weaning. 4. Histological findings in the digestive epithelium of the piglet

In studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with conventional concentrate feeding (I) after an early weaning date (30th-35th day of life) over an 8-week period (1st-8th week of keeping). In the rations containing 10% straw (straw-concentrate mixtures), untreated (II), HCl treated (III: HCl treatment without steaming) and partly hydrolyzed straw meal (IV: HCl treatment with subsequent steaming) were used in the feeding. Samples were taken of 4 killed animals each in the 2nd and 8th weeks of keeping for the qualitative histologic assessment of palatum durum, oesophagus and stomach, duodenum and caecum, colon ascendens, colon descendens and rectum. Although significantly lower pH values in the stomach were registered after the feeding of feed mixtures III and IV due to increased acidity (pH value decrease by 1.3 to 1.5 units) in comparison to the values in I and II, the lamina epithelialis of the palatum durum remained intact in all groups and without any signs of cauterization. Equally, considerable changes in the comparison of the feeding groups could not be detected in the structures of the oesophagus and the stomach walls or in the qualitative histologic assessment of the duodenum and the caecum. However, there were clearly distinguishable group specifics with regard to the formation of lymphoreticular tissue in the stomach and for the colon ascendens.(ABSTRACT TRUNCATED AT 250 WORDS)

The merit of using untreated, HCl-treated amd partly-hydrolyzed straw meal in the feeding regime for piglets after early weaning. 3. Parameters of protein, fat, carbohydrates and mineral metabolism in the blood serum of the piglet

In parallel studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with the conventional feeding of concentrate (I) after an early weaning date (30th-35th day of life) over a feeding period of 8 weeks (1st-8th week of keeping). In the rations containing 10% straw (concentrate-straw mixtures), untreated (II), HCl treated (III:HCl treatment without steaming) and partly hydrolyzed straw meal (IV:HCl treatment with subsequent steaming) were tested. In the 2nd and 8th weeks of keeping blood samples were taken from 4 animals of each group and selected parameters of the protein, fat, carbohydrate and mineral metabolism were subsequently ascertained from the blood serum. About half of the total of the 13 selected parameters showed reactions of the intermediary metabolism of the test groups caused by the feeding. With the parameters on the whole varying in the normal physiologic range, a decrease in the blood urea and creatinine concentration and an increase in the blood glucose level were detected after the use of the concentrate-straw mixtures (III and IV) in comparison with the sole feeding of concentrate (I) and partly also in comparison with untreated straw meal (II), their intensity varying in dependence on feeding and test duration. Particularly towards the end of the experiment, an increase of the activity of alkaline phosphatase was also characteristic, which was in negative correlation with the P content of the serum and in positive correlation with growth performance. The physiologic parameters are discussed in connection with the higher growth performance at reduced concentrate expenditure achieved in III and IV in comparison to I and II.

The feeding of differently treated straw materials to piglets after various weaning times. 2. Fatty acids in the large intestine and parameters of protein, fat, carbohydrate and mineral metabolism in the blood serum during the feeding of untreated, HCl-treated and partly-hydrolysed straw meal

In feeding experiments with piglets of the country species variously treated straw materials were used in concentrate--straw meal mixtures after the traditional weaning date (49th day of life) and studies were made of the fermentation of volatile fatty acids (VFA) in the large intestine (colon) and of the concentration of selected parameters of the protein, fat, carbohydrate and mineral metabolism in the blood serum of the animals. The concentrate--straw mixtures with a 10% straw quota contained untreated (II), HCl treated (HCl treatment without steaming, without (III) and with neutralization, IV) as well as partly hydrolysed straw meal (HCl treatment with subsequent steaming, without (V) and with neutralization with CaCO3, VI) were tested in comparison with sole feeding of concentrate (I) and its combination with wheat bran (VII). With regard to the fermentation processes in the large intestine in a comparison of the feeding groups (I-VII) the highest concentration and production quota of VFA was registered in I and the lowest in II. The straw treatment variants (III, IV, V and VI) took a medium position with regard to this and did not differ from each other. After their application of a significant increase in the molar acetate quota was ascertained in comparison with the sole feeding of concentrate (I), which was also characteristic of the other crude fibre sources (II and VII) and was reflected in the extension of the C2: C3 relation. Only few of the total of 15 selected parameters in the blood serum showed reactions of the intermediary metabolism of the test groups caused by feeding. The decrease of the urea concentration in the serum after the feeding of the treated straw materials (III, IV, V and VI) is particularly remarkable. In general, the urea concentration in the serum was negatively related to growth performance of the test groups. The use of HCl treated straw materials (III-VI) proved to be advantageous in comparison to the sole feeding of concentrate (I) and the use of other crude fibre sources (untreated straw meal (II) and wheat bran, VII) in the feeding regime of the keeping stage 'weaned pigs'.

Factors affecting weaning weight in Antarctic fur seals Arctocephalus gazella at South Georgia

Relationships between size, body condition, age and feeding-attendance patterns during pup rearing of female Antacrtic fur seals Arctocephalus gazella and their effects on the timing of birth and weaning, pup weight, growth and condition were studied at South Georgia in 1981–1982. Twenty-seven (6 male, 21 female) mother-pup pairs were followed from birth to weaning. The analysis of maternal effects was limited to female pups because of the small sample size of male weaners. High weaning weight was associated with those female pups whose mothers spent more time ashore attending their offspring. Weaning weight showed no relationship with perinatal duration, number of feeding trips to sea, days at sea or date of weaning. A further 63 mother-pup pairs were analysed for the effects of maternal body condition (weight/length), age and timing of birth on offspring body weight and condition. Pup weight and condition were weakly correlated with maternal age in female pups. Male pups born earlier in the season were heavier and in better condition. Maternal and offspring body weight and condition were unrelated. For the Antarctic fur seal population at South Georgia where the food supply was apparently not limiting in summer, maternal condition and foraging time were subordinate to maternal care on land (as expressed by attendance duration) in determining offspring weight at weaning.

EFFECTS OF DATE OF WEANING ON SUBSEQUENT PERFORMANCE OF BEEF COWS AND THEIR FEMALE CALVES

1233 April/May born calves were weaned either on 30 Sept. (EW) or 31 Oct. (LW) to assess the effects of weaning date on subsequent performance of their dams and female calves. Cows in the EW group lost less weight than those in the LW group in the month of October (0.003 vs. 0.48 kg d−1, P &lt; 0.05). Dam's breed group, year and the interaction between year and age of dam also had significant effects on weight change during October. Cows generally lost weight between weaning and the next calving and the two weaning groups were similar in body weight at calving and reproductive performance. The reproductive performance of the EW and LW female calves were also quite similar. It can be concluded that weaning April/May born calves in September rather than October would not influence the subsequent production of the dams or their female calves, but would probably reduce their maintenance requirements as they enter the cold season in better condition. Key words: Weaning date, beef cows, reproduction, weight changes

EFFECTS OF DATE OF WEANING ON POSTWEANING PERFORMANCE OF BULL CALVES OF THREE BREED GROUPS

The effects of weaning date on feedlot performance and carcass characteristics of 367 bull calves weaned 1 mo apart were compared in a 2-yr study at the University of Alberta ranch at Kinsella, Alberta. The calves belonged to three distinct breed groups. Calves were weaned either on 1 Oct. or 1 Nov., at which time they averaged 157 ± 1.5 and 189 ± 1.7 d of age, respectively. After a 4-wk postweaning adjustment period, calves in each group were fed a mixed diet containing 90% concentrate and 10% hay. During the period between the two weaning dates early-weaned calves gained more (P &lt; 0.05) than their unweaned contemporaries, while the performance of the two groups during their respective adjustment periods was similar. The late-weaned group gained 175 g d−1 more (P &lt; 0.05) and consumed 800 g d−1 more feed (P &lt; 0.05) during the 140-d feedlot test while feed efficiency did not differ between the two groups. Average daily rate of gain from birth to 1 Oct. had a significant influence on feedlot gain (b = 0.42). Although late-weaned calves had a higher rate of growth during the feedlot test, their early-weaned contemporaries were 14.3 kg heavier and 7 d younger at slaughter. Significant differences in gain and carcass traits were observed between the three breed groups, but the interaction between breed group and weaning date was not significant, indicating that calves of different genetic backgrounds respond similarly to the effects of age at weaning. The results indicate that under Alberta's climatic conditions and despite lower feedlot gains, weaning calves 1 mo early is a viable alternative to the customary weaning date. Key words: Beef calves, bulls, weaning date, carcass traits

The influences of nutrition and management on the growth of red deer calves from weaning to 16 months of age

ABSTRACTThe effects of date of weaning, weaning live weight, autumn grazing management and level and pattern of winter nutrition in relation to summer grazing on the live-weight gain of farmed red deer calves to 16 months of age were tested in three experiments.In experiment 1, the effect of two weaning live weights (37 and 46 kg) in September and two levels of autumn and winter nutrition were examined with 48 calves. In October, live-weight gains were positively related to sward height and herbage mass. The calves lost live weight in November. Compensatory live-weight gains of 28 g/day occurred at summer pasture after the low level of winter nutrition. Weaning live weight had a major influence on live weight at 16 months of age.In experiment 2, the effects of maintenance, ad libitum and intermediate treatments were compared using 50 calves given a complete diet in winter. The intermediate treatment consisted of a maintenance followed by an ad libitum level of feeding. Compensatory live-weight gains of 49 g/day occurred at pasture with the intermediate treatment achieving complete live-weight compensation at 16 months of age.In experiment 3, the effect of two weaning dates (19 September and 14 November) on live-weight gain of calves and on the date of subsequent calving of hinds were compared with 34 lactating hinds. There was no difference in live-weight gain of calves between weaning dates but the subsequent calving date was delayed by 8 days from those hinds weaning in November.A management system is advocated with weaning in September, housing in November after grazing sown swards greater than 6 cm, a pattern of a low followed by a high level of nutrition in winter and the summer grazing of sown swards maintained at 4 to 6 cm.

Evaluation of partial weaning and treatment with PG600 at weaning in relation to subsequent reproduction in the sow.

’Partial’ or ‘split’ weaning involves the earlier weaning of part of the litter before the normal weaning date. There have been isolated reports which claim that such a practice can reduce final weaning to service and conception interval and increase the size of the subsequent litter. However, these possible effects have not been quantified adequately and accordingly a study was carried out to further evaluate this practice.The study was conducted on a 700 sow commercial unit in Aberdeen-shire with crossbred Large White (LW) x Landrace (LR) sows mated to LW, LR or LW x LR boars. Sows and litters were accomodated in conventional farrowing pens and weaning took place when litters averaged 17 days of age. Following weaning, sows were transferred to dry sow stalls adjacent to boar pens. Newly weaned pigs were transferred to flat-deck nursery accomodation.

Partial weaning. The growth of smaller piglets remaining on the sow following the earlier weaning of larger litter mates, relative to equivalent piglets in control litters.

With progressive reduction in piglet mortality and increase in the number of piglets reared for litter over recent years, there has been interest in weaning the larger piglets in large litters several days prior to the planned final weaning date in an attempt to improve the growth rate and size of the smaller piglets prior to weaning. Such prior removal of larger piglets before their smaller litter mates are weaned is termed ‘partial’ or ‘split’ weaning’ and this practice was evaluated in a controlled experiment in terms of the liveweight gain to weaning of the smaller piglets within the litter.

The effects of liveweight at weaning, date of weaning and winter nutrition on the subsequent performance of red deer

A desirable liveweight for red deer at 15 months of age is approximately 80 kg. This will provide a saleable carcase and a liveweight at which yearling hinds will successfully breed. Live-weight at 15 months will be influenced by a large number of factors including date of birth, birth-weight, liveweight gain to weaning, date of weaning, liveweight gain during the first winter and subsequent summer, and the interactions between weaning weight and subsequent levels of nutrition and between winter levels of nutrition and liveweight gain at pasture in the following summer. These latter two aspects were examined in two experiments and the effect of date of weaning on contemporary calf growth rates and on hind calving date in the following year were studied in a third experiment. The objective was to provide information which would allow the development of effective systems of deer meat production based on slaughter at 15 months of age.

Energy requirements for gestation and lactation in a delayed implanter, the American badger.

1. Two adult female badgers were water-deprived and/or fasted during the last one-half to two-thirds of pregnancy while a third pregnant female received water ad libitum and was fed meat and dog food. 2. The litter size, birth weights, post partum energy consumption, growth rate, development of homeothermy, tooth eruption and date of weaning, as well as other developmental characteristics, were not significantly different between cubs born to the fed or fasted mothers. 3. The energy demands for gestation are apparently small and are accommodated by fat reserves during periods of food deprivation. However, the calculated energy for lactation is 16 times that of gestation, which is quadruple the expenditure for most mammals. 4. As a result of delayed implantation, the length of gestation and litter weights of badgers are considerably below those predicted from allometric equations. 5. The period of lactation is therefore extremely critical to the survival of both the cubs and lactating adults which require heavy fat stores and possibly torpor to ensure sufficient energy availability during prolonged winter food shortage.

Parameters affecting survival of Weddell seal pups (Leptonychotes weddelli) to weaning

We examined birth dates, onset and duration of molt, spacing of females and pups, onset and date of weaning, and post-weaning dispersal of Weddell seal pups (Leptonychotes weddelli) in breeding colonies from 1976 to 1979. Survival of pups to weaning was most influenced by their date of birth, their ability at a very young age to haul out on the ice, and the stability of the fast ice during their weaning. The onset and duration of molt was variable; neither a long molt nor an early molt adversely affected pups. Pups born late in the season were not weaned at a younger age. Exclusive space for females and pups in the colony was most important immediately after a pup's birth. Pups born during the optimal pupping period and in years of stable fast ice had a high probability of survival.

ENVIRONMENTAL AND GENETIC EFFECTS ON PREWEANING PERFORMANCE OF CALVES FROM FIRST-CROSS COWS. II. GROWTH TRAITS

Environmental and genetic effects on preweaning growth traits were evaluated for 4034 calves born and 3732 calves weaned in second and later parities from contemporary populations of first-cross dams maintained at two locations, Brandon and Manyberries. The calves were sired by Chianina (Chi), Charolais (C), Limousin (L) and Simmental (S) bulls mated to 10 F1 dam crosses representing the Hereford × Angus (HA) and nine dam-cross combinations produced by matings of C, S and L sires with H, A and Shorthorn (N) females. Sex differences were important (P &lt; 0.0001) with males averaging 7% heavier at birth and 5% higher in measures of postweaning growth than females. Location differences were negligible for birth weight (1.2%), but preweaning growth rate was 10–13% greater at Brandon (P &lt; 0.0001) than at Manyberries. Year differences were large for all traits measured (P &lt; 0.0001) and, with the exception of birth weight, were related to differences in annual weaning date. Progeny rankings by terminal sire breed were Chi &gt; C (2.5%), Chi &gt; S (4.2%), and Chi &gt; L (11.4%) for birth weight (all P &lt; 0.0001) and Chi = C = S &gt; L by 6% (P &lt; 0.0001) for all measures of preweaning growth. Ranking of the dam crosses by their breed of sire (DS) were C &gt; S &gt; L for birth weight (P &lt; 0.0001) and S &gt; C &gt; L for preweaning growth (P &lt; 0.0002). The paired DS comparisons indicated S &gt; L by 9.1% and C &gt; L by 2.7% for growth rate. Ranking of the dam crosses by their breed of dam (DD) were H = N &gt; A (P &lt; 0.0001) for birth weight and [Formula: see text] for preweaning growth traits. A location × dam cross interaction was evident for the Charolais × Shorthorn dam cross (P &lt; 0.01). Progeny from all dam crosses except the LH and LA at Manyberries grew more rapidly than their contemporary controls (HA progeny) with the Simmental crosses averaging 11–14% higher than the HA. Genetic interactions involving breed of sire and breed of dam were absent. Key words: Beef cattle, crossbreeding, preweaning growth