Weaning System Research Articles

The environmental requirements of the early-weaned pig

Early weaning represents a critical period in the life of a piglet since it is an abrupt process which removes the piglet from the comfort of the mother and the ad libitum supply of feed which she provides. Although the age at which piglets are weaned is variable, economic pressures encourage weaning at an early age as a means of shortening the reproductive cycle of the sow and thus improving her output. If a system of early weaning is to be successful it must supply the correct nutrition, enhance the natural disease resistance and provide an environment which creates least thermoregulatory demand on the animal. In addition, it should minimise disease challenge and avoid stressors such as those caused by overcrowding and inappropriate structural surfaces.

The development of digestive capacity in young pigs: effects of age and weaning system.

The development of digestive capacity in young pigs: effects of age and weaning system.

Nutrition and Management of Early-Weaned Pigs: Diets for Protecting Rotavirus-Exposed Pigs Weaned at 1 to 5 Days of Age

The feasibility of early weaning systems depends in part on the control of rotaviral infection in newly weaned pigs. Diets containing antibodies to rotavirus were tested to determine whether deaths (rotaviral infections) could be controlled in pigs that were farrowed “conventionally” at a commercial farm and reared artificially at our research facility. Three sources of antibody were tested: (1) fresh milk from a cow immunized against swine rotavirus, (2) fresh pooled cows' milk and (3) pooled cows' colostrum. Pigs were from two farms where the level of rotavirus in the farrowing environment was thought to be typical of that in North Carolina and beyond. In trial 1, on farm I, pigs that had nursed for about 1 day were brought in groups to the isolated, fumigated research facility. This trial was designated “all in, all out.” Under these conditions, the presence of antibody in the diet, prepared either from milk from the immunized cow or from pooled cows' milk, was effective in reducing mortality: (mortality rate among pigs fed these diets was 4.5% by 2 weeks of age vs 27% for the controls; P<.05). In trial 2, on farm I, the level of rotavirus was built up by the continuous introduction of newly weaned 1-day-old pigs into our rearing environment. This trial was called “continuous.” Under these conditions, the diets used in trial 1 were ineffective in controlling mortality (65% or more deaths; P<.05). In trial 3, on farm II, pigs whose survival was thought to be unlikely were weaned at 1 to 5 days of age and brought in groups to the fumigated rearing facility. This trial was called “all in, all out; disadvantaged.” Under these conditions, the diets containing the low level of antibody, either from the immunized cow's milk or from pooled cows' milk, were partially effective (mortality rates of 23%, P<.05, and 34%, P<.1, respectively, vs 53% for the controls). The most effective diet contained cows' colostrum diluted at 1:10 (3% deaths, P<.05), but a diet containing the cows' colostrum diluted at 1:20 was ineffective (55% deaths).

Admixture of Atmospheric Air in the T‐piece Used as a Weaning System

Ayre's T-piece may be used for intubated, non-anaesthetized patients requiring an oxygen supplement or humidified gas mixtures. The system has the disadvantage that atmospheric air (VAD) enters through the expiratory leg when the inspiratory flow and therapeutic gas flow (TGF) are not equal. This admixture can be reduced in the simple T-piece by the addition of either a compliant inspiratory reservoir, or a compliant inspiratory reservoir and an expiratory unidirectional valve. These three systems have been studied in a model investigation using different tidal volumes (VT), respiratory frequencies, and therapeutic gas flow. VAD was measured using a pneumotachograph and the inspiratory tidal volume was measured with a Wright Respiratory Monitor. The ratio VAD/VT was employed as an expression of the admixture of atmospheric air during inspiration. The introduction of a compliant inspiratory reservoir to the simple T-piece results under all conditions in a considerable reduction in VAD/VT. A further reduction was obtained by introducing an expiratory unidirectional valve into the system - however, with the result that the previously open system is turned into a closed system. When selecting a weaning system, the risk to the patient of the discontinuation of the gas flow should therefore be weighed against the advantages obtained by a reduction of the admixture.

REPRODUCTIVE PERFORMANCE OF THE SOW SUBSEQUENT TO WEANING PIGLETS AT BIRTH

Eighty-eight sows at two locations were used to study the effects of removal of piglets at, or within a few hours of, birth (zero-weaning) on subsequent reproductive performance. Zero-weaning resulted in an increase in the interval from farrowing to conception, a concomitant increase in the farrowing interval, an increased incidence of cystic ovarian degeneration and a reduced conception rate as compared to control animals weaned approximately 30 days postpartum. There was no significant effect on subsequent litter size. Based on plasma progesterone analysis zero-weaned sows ovulated on the average 17.0 ± 6.6 days postpartum. Attempts to establish ovarian cyclicity 48 h postpartum were not successful in terms of sows being rebred any earlier than would be possible with a 21-day weaning system. The results indicate that zero-weaning may not result in improved sow productivity in terms of achieving a greater number of litters per sow per year.

Protein for Calves on a Limited Milk-Early Weaning System

Complete pelleted calf starter rations were fed to Holstein heifer calves on a limited milk-early weaning program from 3 days to 12 wk of age. Five rations fed to each of 10 calves were to contain crude protein percentages of 10, 12.5, 12.5 with .7% urea, 15, and 15 with 1.1% urea (as fed). The digestible protein:digestible energy ratios (g digestible protein/Mcal digestible energy) of the rations (in same order) were 23.4, 30.7, 28.8, 36.4, and 41.5. Average birth weight was 42.9kg and weaning weight at 4 wk, 52.8kg. Treatment effects on feed intake, average daily gain, and feed efficiency were analyzed after adjustment of birth weight and removal of effects of block and location. Feed intake for 12 wk was greater for 15% crude protein with 1.1% urea than for either 12.5% ration but not different from 10% protein. Average daily gain was increased for both 15% protein rations compared to 10 or 12.5% protein. Gain by calves fed 10% protein was equal to that by those fed 12.5% protein. Feed efficiency during wk 5 to 12 was improved for 15% with vegetable protein compared to 10% crude protein or the 12.5% crude protein ration with vegetable protein. There were no differences in intake, gain, or efficiency between urea and vegetable protein.

The replacement of skim milk by dried microbial cells and whey in milk diets for calves

In two experiments, the performance and health of calves fed on diets containing dried microbial cells (DMC) was monitored. In the first experiment 32 seven-day-old British Friesian bull calves, reared on a conventional early weaning system to 8 weeks of age, were given milk replacers in which 5, 10 and 20% spray-dried DMC and whey replaced 14–55% of skim milk protein. All DMC diets contained 36 g/kg of non-nucleic acid nitrogen. In Experiment 2, 38 two-day-old Ayrshire bull calves were fed for 63 days solely on one of two milk diets containing 0 or 10% DMC at 5 levels of intake designed to produce body gains of 0–1 kg/day. While the inclusion of up to 10% DMC in both experiments had little effect on performance or health, 20% DMC was associated with severe diarrhoea, loss of appetite and growth retardation, and impaired clotting of the milk in vitro. In Experiment 2 the response, in gain, by calves given increasing intakes of milk dry matter was linear and was unaffected by the type of diet offered. It was concluded that when levels of DMC in excess of 10% inclusion are used in association with maize starch, deleterious effects on performance are likely.

Effect of early weaning on the performance of male buffalo and cattle calves

SUMMARYForty-eight uncastrated buffalo male calves and 16 male Friesian × Egyptian Native calves were used in two experiments to study the effect of weaning age on the performance of calves fed on a high concentrate ration after the first four months of age. Half of the buffalo calves were weaned at 120 days of age on to 330 kg whole buffalo milk (late-weaned) and the other half were weaned at 45 days of age on to 100 kg whole buffalo milk (early-weaned). Cattle calves were weaned at 31 days of age on to 65 kg whole cow milk. At the age of 7 days the calves were put on a high energy ration of 74% total digestible nutrients and 13·5% digestible protein. After 125 days of age all calves were offered a high concentrate ration (cottonseed cake and rice bran in the ratio of 1:1, plus 2% Ca(OH)2 and 1% common salt). Air-dried roughage was supplied at a level of ½% of the body weight. Buffalo and f-Native calves reached a slaughter weight of 400 kg or more about 540 days of age. Three-quarters Friesian calves reached the same weight at 480 days of age. The high concentrate ration caused a high incidence of bloat in ¾Friesian bulls. The efficiency of feed utilization was better for cow calves than that for buffalo calves. The system of early weaning of buffalo calves proved to be most economical and saved about 26% of the cost per kg live-weight gain. Slaughter experiments indicated that fat deposition was greater in male cattle of 400 kg than in buffalo bulls.

A practical assessment of early weaning

The rearing and economic results from normal weaning systems are highly variable; this is also true for early weaning, not only because it is a new system, but because thesystem depends more upon the farmer and much less upon the sow. Farmers like early weaning particularly because of its labour-saving aspects. In the first part of the paper I shall give a survey of the causes of differences in rearing results we have obtained from different farms and rearing centres. The second part will examine what is currently the major problem of early weaning systems, the subsequent reproductive performance of the sow.

Establishment of Rumen Ciliate Protozoa in Cow and Water Buffalo (Bos bubalus L.) Calves Under Late and Early Weaning Systems

Establishment of ciliate protozoa in the rumens of cow and buffalo calves kept under early and late weaning systems was studied. The results showed that the rumens of the buffalo calves harbored active populations of ciliate protozoa at earlier ages than those of cow calves, probably indicating earlier rumen development in buffalo calves. Early weaning promoted faster establishment of ciliate protozoa than late weaning, especially in cow calves. The effect was not so clear in buffalo calves. Entodinium spp. were first to appear in the rumen. Eudiplodinium was established as soon as Isotricha in the early-weaned cow calves, while large oligotrichs appeared at an earlier date in buffaloes.Cross-inoculations among buffaloes, cows, and sheep showed that Ophryoscolex and Polyplastron from sheep failed to survive in adult or young cows and buffaloes, thus demonstrating host specificity. Epidinium was not observed in the rumen contents of sheep, cows, or buffaloes maintained under Egyptian conditions.

Feed Efficiency, Ruminal Activity, and Effects on Some Blood Constituents of Early Weaned Calves

Twenty-seven three-day-old bull calves were distributed among two groups: 1) Control calves were weaned at 87 days and received 270kg whole milk and 2) calves in Group 2 were weaned at 31 days and given 115kg whole milk plus a calf starter ration consisting mainly of sorghum seeds, sesame cake, dry alfalfa leaves, and cane sugar.The control calves made more efficient gains than the early weaned ones. The system of early weaning saved about $25.50 per calf compared with the cost of rearing the control calves for the same period. The early weaned calves were superior to those normally weaned in utilizing roughage after weaning.The results of rumen microbial activity and blood constituents showed: 1) Total volatile fatty acids increased with age in the two groups and were higher in the early weaned calves; 2) there were no differences between the two groups in concentrations of ruminal ammonia and blood urea and ammonia nitrogen. Some parallelism was evident between changes in ammonia N in the rumen and blood urea and ammonia N; and 3) inoculation with rumen contents resulted in establishing active populations of ciliate protozoa in only the early weaned calves.

Effect of Feeding Broken Rice Grains and Decorticated Cottonseed Meal on Feed Efficiency, Ruminal Activity, and Blood Constituents of Early Weaned Buffalo Calves

Thirty-nine female ten-day-old buffalo calves were distributed among five groups: 1) control calves were weaned at 120 days and received 340kg whole buffalo milk; 2) calves in Groups 2 and 3 were weaned at 45 days and given 103.3kg whole milk; the last two groups were weaned at 31 days after being fed the same quantity of milk. The calves in Groups 2 and 4 were given starter ration 1 (corn, barley, linseed meal, and beans). The two other groups (3 and 5) were given starter ration 5 (corn, barley, linseed meal, beans, broken rice grain, and decorticated cotton-seed meal).Ration 1 stimulated significantly better growth and gave a higher feed efficiency than Ration 5 when calves were weaned at 45 days. Calves weaned at 31 days in general were inferior in size to those weaned late, or at 45 days. The system of early weaning of buffalo calves at 45 days after receiving 103.3kg of milk and starter ration 1, which was gradually replaced after 45 days by Ration 2 (rice bran and decorticated cottonseed meal), has proved to be most economical, and saved about $22 per calf in 120 days, compared with the cost of rearing late weaned calves for the same period. The results of rumen microbial activity and blood constituents showed: 1) ammonia N was higher at two weeks and decreased to eight weeks of age; 2) total volatile fatty acids (VFA) increased with age up to 6–12 weeks and was higher in groups fed ration 1; 3) microbial N was significantly higher in the rumen of early weaned calves than in late weaned calves and decreased with age; 4) blood urea and ammonia N concentration were highest at two weeks of age and decreased to 6-10 weeks. Some parallelism was evident between changes in ammonia N in the rumen and blood urea and ammonia N; and 5) blood reducing sugars and hemoglobin decreased to eight weeks of age. The blood reducing sugars of early weaned calves were lower than those of the late weaned calves.

A note on the effect of certain variables on the performance of early-weaned calves

Although numerous studies on the early weaning system of calf rearing have given information concerning the composition of milk substitutes and concentrate rations which may be used, and the subsequent growth rates which may be expected, few have given information concerning either the relative effects on subsequent growth rate of initial weight, weaning weight, concentrate and hay intakes, or the relationships which exist among these factors themselves.

Value of Hay and Rumen Inoculation in an Early-Weaning System for Dairy Calves

Summary Twenty-eight Holstein bull calves were used on a 21-day weaning system to determine the value of cud-inoculation and feeding of hay free-choice or incorporated into the starter. The calves were divided into four groups: Group I, Starter A with hay free-choice from 43rd day; Group II, Starter A with hay free-choice from eighth day; Groups III and IV, Starter B with 32.55% hay incorporated. The first three groups were inoculated at 14, 21, 28, 35, and 42 days of age. Calves in the four groups gained an average of 1.04, 1.12, 1.09, and 1.00 lb, respectively, during the eight- to 70-day experimental period. The differences were not statistically significant. Starter consumption increased rapidly as milk was withdrawn. Feed intakes and utilization after 21 days of age were adequate for maintenance plus a satisfactory weight gain. The two groups of calves fed hay free-choice consumed 12.4 and 18.2 lb hay during the experiment, compared to 58.9 and 53.8 lb by calves fed hay incorporated in the starter. Calves fed the starter with hay incorporated consumed 28.5 lb less grain and gained 2.2 lb less weight. Thus, hay can not only be force-fed at an early age but it can be utilized by the calf. When hay was offered free-choice, some calves consumed very little. As a consequence, there was less rumen development and, in some cases, hyperkeratosis of the rumen, erosion of the rumen wall, and rumen plaques. Cud-inoculation had little value in the 21-day weaning system.

The early weaning of pigs: II. The performance up to 56 days of age of pigs weaned at 8, 14 and 20 lb. live weight

Groups of pigs were weaned at 8, 14 and 20 lb. live weight from each of seven litters. Each of the twenty-one groups was housed separately and selffed a 30% protein diet ‘A’ up to 25 lb. live weight.From then until 56 days of age each group was selffed a 22% protein diet ‘B’.Weight at weaning had no significant effect on age at 40 lb. live weight, but weights at 56 day old of 46·5, 50·2 and 47·7 lb. for pigs weaned at 8, 14 and 20 lb. respectively tended to favour weaning at 14 lb. (P &lt; 0·10).Pigs weaned at 8, 14 and 20 lb. each required 25, 16 and 6 lb. respectively of expensive diet ‘A’ to reach 25 lb. live weight. To grow from 25 to 40 lb. live weight they each required 30, 28 and 27 lb. of diet B, and this trend in favour of the pigs weaned at heavier weights was significant at P &lt; 0·05.These results are discussed in relation to the system of early weaning.