Jean-Yves Dourmad

The effect of energy and protein intake of sows on their longevity: a review☆

Abstract The characterization of the effects of protein and energy intake of sows on their longevity requires long-term experiments involving large numbers of females. Results from the studies available show that sows are culled mainly for reasons involving reproductive failure, locomotion problems or poor lactation performance. Energy under-feeding during gestation is associated with lower body fat reserves at farrowing or at weaning and generally return to oestrus is delayed and conception rate is lower. On the contrary, over-feeding during gestation increases weight and condition of the sow at the end of pregnancy and this can affect the occurrence of farrowing and lactation problems and culling for poor lactation performance or locomotion problems. During lactation, it seems that there are critical levels for energy and for protein below which weaning to oestrus interval, rate of return to oestrus and pregnancy rate are affected, especially in primiparous sows. This is the main reason for early culling of sows. The mechanisms are not yet elucidated, but the metabolic status or the status of body reserves of the sows at weaning seem to be involved. It is thus necessary to apply a feeding strategy adapted to each sow, in relation to its own level of production, its behaviour and the housing conditions, in order to maintain body reserves within an optimal zone all along the reproductive life and to maximize its longevity.

Effect of feeding level in the gilt during pregnancy on voluntary feed intake during lactation and changes in body composition during gestation and lactation

Abstract Forty-eight Large White gilts were divided at mating into three feeding groups: low (L), medium (M) and high (H). The gifts of groups L, M and H were fed 1.8, 2.25 and 2.7 kg/day during pregnancy of a diet containing 17% protein, respectively. They were given the same dict ad libitum during lactation. Reproductive performances during gestation and lactation were similar in the three groups. Net weight gain during pregnancy and backfat depth gain increased linearly with feeding level: 37.1 kg and 4.2 mm, 53.3 kg and 8 mm and, 64.3 kg and 11.4 mm in groups L, M and H, respectively. Feed intake during lactation was significantly affected by pregnancy treatment, especially during the first week. A negative relationship was established between backfat depth at farrowing and lactation feed intake: -63 g day -1 mm -1 during the whole lactation and -95 day -1 mm -1 during the first week. A positive relationship was also found between body weight gain during pregnancy and weight loss during lactation. The results show that predicted muscle weight loss during lactation increased with pregnancy feeding level whereas predicted fat weight loss was affected only by level of feed intake during lactation. Weight gain from mating to weaning was positive in all treatments: +24.9, +33.6 and +39.7 kg for groups L, M and H, respectively, whereas backfat depth decreased by 4.1, 2.2 and 0 mm for groups L, M and H, respectively. This shows the limits of a feeding strategy based only on the target of weight gain.

Effect of energy intake on the performance of different types of pig from 45 to 100 kg body weight. 1. Protein and lipid deposition

Between 45 and 100 kg body weight, Large White castrated males (cLW), and crossbred Pietrain × Large White castrated males fcPP×) and boars (bPP×) were either given food ad libitum in experiment 1 or allocated to four energy levels (0·70, 0·80, 0·90, 1·00 ad libitum) in experiment 2. Daily protein and amino acid supplies were calculated to be non-limiting for growth. Protein (PD) and lipid (LD) deposition rates were measured according to the comparative slaughter technique over the whole experimental period (experiments 1 and 2) and according to the nitrogen and energy balance technique at four stages of growth: 48, 64, 79 and 94 kg mean body weight (experiment 2). Average daily gain increased linearly with metabolizable energy (ME) intake, the slope of the relationship being significantly different between types of pig (from −28 to +36 g per additional MJ ME). Daily PD increased with ME intake above maintenance (MEp) according to a linear-plateau relationship in the three types of pig: the slope was significantly affected by type of pig (from +3·4 to 6·0 g per extra MJ MEp) but not by stage of growth. Daily LD increased linearly with MEp intake; neither the type of pig nor the stage of growth affected its slope (+13-5 g per extra MJ MEp). The LD/PD ratio in the extra body-weight gain associated with increased energy intake was affected only by the type of pig.

Effects of zearalenone or glucosinolates in the diet on reproduction in sows: A review

Abstract This review deals with the effects of intake of two important kinds of antinutritional factors on sow reproduction: a mycotoxin, zearalenone, and glucosinolates from rapeseed meal. Emphasis is given to their way of action on which numerous works were undertaken during the last years. Unlike a nutrient imbalance whose effects generally appear at long-term and are difficult to cure, the influence of antinutritional factors is observed rapidly, concerns many parameters and disappears when their intake is disrupted. Zearalenone, which is produced by some Fusarium strains, contaminates cereals harvested in damp conditions. It is characterized by its oestrogenic properties which induce vulvovaginitis in premature gilts, anoestrus in cycling females or delayed return into oestrus after weaning of the sows. During pregnancy, zearalenone reduces embryonic survival when fed beyond a threshold level, and sometimes decreases foetal weight. It could affect uterine environment by decreasing LH and progesterone secretion and modifying the morphology of uterine tissues. Rapeseed meal contains glucosinolates whose some by-products have anti-thyroidic properties. During pregnancy, they induce a thyroid hypertrophy in sows and foetuses. Foetuses are especially sensitive since their T4 level in plasma and their liveweight before birth decrease in relation with the glucosinolate level in maternal diet. All harmfull consequences are avoided when glucosinolate level in the diet remains below 2 μM/g. Thus, use of rapeseed cultivars with a very low glucosinolate content, obtained through selection, allows the feeding of reproductive sows with diets containing high levels of rapeseed meal.

Nitrogen and phosphorus consumption, utilisation and losses in pig production: France

Abstract Although pig density in France (80 pigs produced/year/km2) is lower than on average in the European Union (140 pigs/year/km2), some regions with intensive animal production (720 pigs/year/km2) have to face environmental problems related to a surplus of animal manure. According to the legislation, the amount of nitrogen from animal manure should not exceed 170 kg/ha. The actual situation for nitrogen and phosphorus consumption, utilisation and losses in pig production in France is described in this paper. It was calculated that on average 67% of the N and 66% of the P consumed by the pigs is excreted in faeces and urine. Improvements in feeding techniques could reduce by 15 to 30% N and P excretion by the animals, and ammonia losses in the atmosphere. The nutritional basis for these improvements is described.

Ammonia emissions from pig houses in The Netherlands, Denmark and France

In recent decades pig production has been intensified in most European countries. This has resulted in a surplus of manure and a serious concern about the effect of ammonia emissions on environmental acidification and the pollution of ground and surface water. In the Netherlands, Denmark and France approximately 50% of the ammonia emissions from pig production is from pig housing and slurry storage. Ammonia emissions from pig houses can be reduced by: (1) lowering the concentrations of urea and ammonia in the slurry; (2) lowering the temperature of the slurry; (3) reducing the emitting surface area; (4) reducing the pH of the slurry. Various housing techniques have been developed to reduce ammonia emissions. Most of these techniques are costly but cheaper systems are becoming available. A combination of housing and feeding measures seems most promising to achieve a substantial reduction in ammonia emissions at relatively low costs. Lowering the protein content of the diet, including non-starch polysaccharides and adding acidifying salts instead of CaCO3 are the main possibilities at the moment to reduce the ammonia emission by dietary means.

The effect of dietary fibre on energy utilisation and partitioning of heat production over pregnancy in sows

A low (L) and high-fibre (H) diet were fed to six multiparous sows during gestation in a 2 x 2 repeated Latin square design. A single meal per day was given that provided 37.2 MJ digestible energy/d. The kinetics of heat production (HP) and its partitioning (fasting HP, activity HP, and thermic effect of feeding (TEF)) were determined. The TEF was partitioned between a dynamic component (TEFst) and a constant component (TEFlt). Digestibility of energy and nutrients was lower for the diet H. In spite of the lower metabolisable energy (ME) intake (33.9 v. 35.4 MJ/d for diets H and L respectively), HP was higher for diet H (30.5 v. 28.9 MJ/d) resulting in a lower energy retention. The estimated fasting HP was 270 kJ/kg body weight 0.75 per d at day 0 of gestation and increased with advancement of pregnancy. The TEFlt was not significantly different from zero for diet L, but represented 4.1% of ME intake for diet H. The TEFst was not affected by the diet but diet H delayed the postprandial peak of HP. Total TEF was higher for diet H than for diet L (11.7 v. 8.2% of ME intake). The longer duration of eating with diet H was compensated for by less physical activity between meals, so that activity HP was equivalent for both diets. The activity HP represented 20% of ME intake but was variable between sows. The ME requirements for maintenance averaged 440 kJ/kg body weight 0.75 per d. Feeding high-fibre diets increases HP, delays the postprandial peak of HP and maintains the basal HP at a higher level.

Dietary fiber for pregnant sows: influence on sow physiology and performance during lactation.

This study was conducted to investigate the effects of feeding sows a bulky diet during gestation on their physiological and metabolic adaptations during the peripartum period, and to determine how these effects may relate to sow and piglet performances. From d 26 of gestation until farrowing, gilts were fed diets that contained 2.8 or 11.0% crude fiber (control and high-fiber diets, respectively, n = 9/group). Daily feed allowance provided the same amount of DE daily (33 MJ of DE/d). Throughout lactation, sows were allowed to consume a standard lactating sow diet ad libitum. Litters were standardized to 12 piglets beyond 48 h after birth. On d 105 of gestation, a jugular catheter was surgically implanted. Preprandial blood samples were collected from d 109 of gestation to the day after farrowing and on d 4, 18, and 26 of lactation. Meal tests and glucose tolerance tests were performed on d 109 of gestation and d 4 and 18 of lactation. During gestation, BW and backfat gain did not differ between treatment groups. During lactation, sows fed the high-fiber diet ate an average of 0.94 kg/d more than control sows (P < 0.02). Piglets born from sows fed the high-fiber diet grew faster than piglets from control sows (P = 0.03). Body weight and backfat losses did not differ between the 2 treatment groups. Sows fed the high-fiber diet during gestation had lesser concentrations of leptin before farrowing than control sows (P < 0.01). Leptin concentrations were negatively correlated with feed intake during lactation (P < 0.05). The prepartal increase in prolactin concentrations tended to be greater in sows fed the high-fiber diet than in control sows (P < 0.1). Preprandial concentrations of glucose, NEFA, lactate, and IGF-I fluctuated over time without significant treatment effect. Glucose half-life was shorter in late gestation than during both stages of lactation, but did not differ between sows in the 2 groups. In late gestation, the postprandial increases in glucose and insulin were delayed, and smaller, after a high-fiber meal than after a control meal. During lactation, glucose and insulin profiles after a standard meal did not differ between sows from treatment groups. In conclusion, the greater appetite of lactating sows fed a high-fiber diet during gestation does not seem related to changes in glucose and insulin metabolism and may be partly due to decreased secretion of leptin. The greater feed consumption was accompanied by a faster growth rate of piglets without sparing effect on maternal body reserves.

Effect of weaning-to-conception interval and lactation length on subsequent litter size in sows

Abstract A retrospective study of the effects of weaning-to-conception interval (WCI), lactation length and their interaction with selected factors on subsequent litter size has been performed on sows born in 1990 in the French herd. Results from 1881 herds and 46,523 sows were analysed. Sows raised outdoors weaned significantly fewer piglets than those raised indoors. The effects of lactation length, breed, parity, age at first service and WCI on litter size were studied on animals raised indoors. Repeatabilities of litter size and WCI were low, and comprised between 0.20–0.24 and 0.11–0.15, respectively. Sows conceiving within 5 days after weaning farrowed larger litters, whereas litter size decreased when animals were bred on days 6 to 10. Late first-mated gilts has a larger second litter. However, the decrease in subsequent second litter size due to increase in WCI interval was similar for sows in different ‘age at first service’ classes. The effect of WCI on subsequent litter size was more pronounced in pure Landrace than in Large-White or crossbred sows, and in parity 2 than in further parities. Two optimal values for both litter size and WCI were observed for weaning, at either 21 or 28 days. Results indicated that management policies, and particularly lactation length, played a major role on sow performance.

Effect of ambient temperature and addition of straw or alfalfa in the diet on energy metabolism in pregnant sows

Abstract Twelve pregnant multiparous Large White sows (Trial 1) were kept individually in respiration chambers for 35 days at ambient temperatures which changed (by 3°C steps) from 23 to 8°C and then from 8 to 23°C (3 days at each temperature). Sows (4 per treatment) were fed a basal diet (Treatment 1) or the basal diet supplemented either with wheat straw (Treatment 2) or alfalfa meal (Treatment 3). In Trial 2, four sows were maintained successively at 20, 14 and 8°C (8 days at each temperature). At each temperature, they were given 2.1 and 2.7 kg of basal diet (Trial 1, 4 days at each feeding level). Energy and nitrogen balances were carried out. Reduction of ambient temperature induced a curvilinear increase of heat production, the rate of change being as high as temperature or feeding level were low. Consequently, additional daily feed requirement for compensating the effect of cold varied between 45 to 85 g °C −1 , according to ambient temperature or feeding level. Reduction of ambient temperature was associated with an increase of the efficiency of utilization of additional metabolizable energy (ME). Feedstuffs such as straw which are utilized with a low efficiency at thermoneutrality have, relative to standard feedstuffs, a higher energy value when animals are kept in the cold. Critical temperature was 20–23°C. Maintenance requirements of multiparous sows (425–435 kJ ME kg −0.75 ), which were comparable to those of primiparous females, are influenced by the activity of the animals. Nitrogen retention was depressed in the cold. Digestible and metabolizable energy values of wheat straw were 4.3 and 4.2 MJ kg −0.75 dry matter, respectively. Corresponding values for alfalfa meal were 8.5 and 7.4 MJ kg −1 dry matter.