Feeding behaviour feedback signals ruminant gastrointestinal tract metabolites and hormones central nervous control integrative theories of food intake control growth and fattening reproduction and lactation diet digestability and concentration of available energy specific nutrients affecting intake learning about food - preferences diet selection appetites for specific nutrients environmental factors affecting intake the intake of fresh and conserved grass prediction of voluntary intake. Appendices: particular features of poultry and ruminant animals outline programme to identify and store meals from the identities of animals and weights of food containers.

Voluntary food intake and diet selection in farm animals.

Lactation in the sow during heat stress

This review of sow welfare addresses all aspects of housing for adult female pigs, including the issue of piglet welfare during lactation. It puts the issue of sow welfare in perspective by briefly outlining different approaches to the scientific assessment of welfare, the 'feelings, preference, nature, and the functional or home- ostasis' approaches. We believe the last approach currently offers science the best assessment of welfare and is the approach that is utilised in this review. It involves comparing housing or husbandry systems and risks to welfare on the basis of relative changes in biological (behavioural and physiological) responses and corresponding decreases in fitness (growth rate, reproductive performance, or health/injury/immunology). The review discusses the following areas: (i) housing of individually housed pregnant pigs, with subsections on tethers, stalls, reproductive performance, exercise, and new stall designs; conventional, alternative, and outdoor group housing with subsections on aggression, electronic feeding stations, ecoshelters, and other alternative group housing designs; and other issues, such as lameness, culling, straw and other substrates, diet and hunger, quality of stockpeople, and housing around mating including oestrus detection and mating; and (ii) farrowing and lactating pigs with subsections on farrowing crates and alternative farrowing systems, stress around farrowing and during lactation, maternal behaviour and piglet survival, and sow and piglet injury and lameness. Conclusions and recommendations arising from the review include the need for public education to provide an informed consumer base that will result in some consensus on welfare issues among diverse interest groups and the need for industry education that results in better animal welfare and a sustainable industry. Some specific research recommendations include space allowance and the duration of housing for individually housed pigs, welfare issues of breeding sows in ecoshelters, piglet mortality in alternative systems, aggression in conventional and large groups, bedding, and hunger.

A review of the welfare issues for sows and piglets in relation to housing

Multiparous Large White sows (n = 63) were used to investigate the effects of five ambient temperatures (18, 22, 25, 27, and 29 degrees C) and two dietary protein contents on their lactation performance. At each temperature treatment, ambient temperature was maintained constant over the 21-d lactation period. Dietary protein content was either 14 or 17% with essential amino acids levels calculated not to be limiting. The animals had ad libitum access to feed between the seventh and the 19th day of lactation. Diet composition did not influence lactation performance. Over the 21-d lactation, feed intake decreased from 5.67 to 3.08 kg/d between 18 and 29 degrees C. Between d 7 and 19, the corresponding values were 7.16 and 3.48 kg/d, respectively. This decrease was curvilinear; an equation to predict voluntary feed intake (VFI) from temperature (T, degrees C) and body weight (BW, kg) is proposed: VFI = -49,052 + 1,213 T - 31.5 T2 + 330 BW - .61 BW2 (residual standard deviation: 1,018). Skin temperature increased regularly with increased ambient temperature (34.6 to 37.4 degrees C between 18 and 29 degrees C), whereas udder temperature reached a plateau at 25 degrees C (38.3 degrees C). The gradient of temperature between skin and rectum was minimal (2 degrees C ) at 27 degrees C and remained constant at 29 degrees C. This constancy coincides with the marked reduction of feed intake. The respiratory rate increased from 26 to 124 breaths/min between 18 and 29 degrees C, and this indicates that the evaporative critical temperature was below 22 degrees C. The BW loss increased from 23 to 35 kg between 18 and 29 degrees C, but its estimated chemical composition remained constant. Pig growth rate was almost constant between 18 and 25 degrees C (241 g/d) and was reduced above 25 degrees C (212 and 189 g/d at 27 and 29 degrees C, respectively). In conclusion, temperatures above 25 degrees C seem to be critical for lactating sows in order to maintain their performance.

Influence of high ambient temperatures on performance of multiparous lactating sows

Data on energy metabolism and body composition changes of the pregnant and lactating sow have been considered in order to propose methods for determination of energy requirements according to a factorial approach. Daily requirements for maintenance at thermoneutrality amounts to about 105 and 110 kcal ME& BW7’ in pregnant and lactating sows, respectively. During pregnancy, maintenance represents 75 to 85% of the total requirements and is affected greatly by environmental temperature and activity of the animals. Requirements for total uterine gain are low, but they increase with advancement of pregnancy. In addition, the daily ME requirements during pregnancy depend on the amount and composition of maternal weight gain and on the previous lactation body weight loss. The factorial approach indicates clearly that daily ME recommendation in pregnant sows varies from 6 to more than 10 Mcal and must be adapted to each sow within a herd. A method for prediction of ME requirements in lactating sows that considers a relatively precise estimate of energy output in milk is proposed. Results indicate that daily ME requirements are particularly high (15 to more than 20 Mcal) and generally are not met by voluntary feed intake. Emphasis also has been given to prediction of body composition changes that occur over the reproductive life of the sow. Data from the factorial approach allow for optimization of sow energy nutrition to ensure a normal evolution of body weight changes and to avoid major changes in body weight and composition. However, no available data demonstrate whether such a strategy is concomitant with optimal lifetime

Energy utilization in pregnant and lactating sows: modeling of energy requirements'

Voluntary feed intake by lactating sows

Three separate trials are described, each involving sows ranging in parity from first to tenth. In the first trial sows were penned either in individual stalls 2.1 m X 0.6 m or individually tethered in stalls 0.6 m wide, from mating to day 110 of pregnancy. Both groups were on insulated concrete floors partially slatted. Results indicate no difference in percentage of pigs born dead or survival to weaning or in post-weaning performance of sows. In the second trial sows were kept in farrowing pens 2.4 m X 1.6 m with the sow restrained in a farrowing crate 0.6 m wide or tethered by the neck in a partial crate 0.6 m wide from day 110 of pregnancy to weaning at 30 days of age. All pens were of insulated concrete without bedding with the rear 0.6 m slatted with cast iron slats. Results indicate no effect of pen type on percentage of pigs born dead, survival to weaning or in post-weaning sow performance. In the third trial sows were housed in groups of 4 on an insulated concrete floor without bedding or in individual stalls after weaning. Boars were present in adjoining pens in both cases. Group housed animals had poorer performance due to a combination of failure to show oestrus, lower conception ratio and loss through injuries due to fighting. Those that did show oestrus had the same weaning to oestrus period as stalled sows and produced slightly (but not significantly) bigger litters.

https://hal.archives-ouvertes.fr/hal-00901493/document

Effect of housing system on sow productivity.

Perinatal mortality in pigs.

Four mating systems were compared in two experiments and herd records were examined to compare sows mated once or twice under a system of planned double mating. In the first experiment, 100 sows were allocated to each of three systems: (i) double mating at 24-hour intervals, (ii) double mating 6-hour intervals, (iii) triple mating in a 24-hour period. Differences in farrowing ratio and litter size showed a small but not significant advantage in favour of triple mating. The farrowing ratios were 90, 89 and 93%, respectively. In the second experiment two systems were compared: (i) double mating at 24-hour intervals and (ii) single mating at the optimum time as indicated by changes in the vaginal mucosa. One hundred and sixty sows were allocated to each treatment. Differences in farrowing ratio and litter size were small and not significant. Herd records for a 5-year period were used to compare performance of sows mated once or twice under a system of planned double mating. Sows mated once under this system farrowed fewer pigs (p < 0.05) and had a lower farrowing ratio (p < 0.10) (77% vs 86%). Measurements made on duration of mating showed very great variation among boars and even between matings by the same boar. Duration of mating was not influenced by parity of sow, breed of boar or the amount of sexual activity by the boar during the previous week. Neither did duration of mating have any clear relationship with litter size. Litter size was poorly related to boar usage, but there was an indication that boars rested for over 7 days before mating produced larger litters.

J. F. O'Grady

Papers

Voluntary feed intake by lactating sows

Effect of housing system on sow productivity.

Perinatal mortality in pigs.

Mating management of sows

Relationship between environmental conditions and sow performance.