Margareta Rundgren

Effect of halothane genotype on muscle metabolism at slaughter and its relationship with meat quality: A within-litter comparison

The effects of halothane genotype on muscle metabolism at slaughter and its relationship with meat quality were studied within 16 litters. Heterozygous boars and sows were mated and the offspring were halothane tested and bloodtyped to reveal the halothane (Hal) genotype of the 120 animals used (NN, Nn or nn). Following slaughter at 100kg live weight, muscle samples from M. longissimus dorsi (LD) and M. quadriceps (Qu) were taken immediately after exsanguination and analysed for glycogen, glucose-6-phosphate, lactate, creatine phosphate (CP), and adenosine triphosphate (ATP), as well as for enzyme activities representing both the oxidative and glycolytic pathways. The enzyme activities were similar for all genotypes. All muscle metabolites differed significantly between samples from NN and nn animals, with higher lactate and glucose-6-phosphate and lower glycogen, CP and ATP in the nn muscles. The heterozygote animals were intermediate or close to either of the homozygotes. Meat quality characteristics (drip loss, surface and internal reflectance and dielectric loss factor) were studied only in the LD muscle. Meat quality of the muscle from the heterozygote (Nn) animals was inferior to that from NN animals (no difference for internal reflectance) but better than that from nn animals. When reflectance and drip loss were combined into an index, very few values from the nn-animals were better than the total mean. Indexes from the dominant homozygotes were generally better than the mean and those of heterozygotes were approximately normally distributed around the mean.

Nursing behaviour of sows during 5 weeks lactation and effects on piglet growth

Abstract The main goal of this study was to investigate the effect of sow nursing behaviour on piglet weight gain and within-litter variation (WLV) in piglet weight gain under as naturalistic conditions as possible. In order to achieve this, patterns of sow nursing behaviour and piglet weight gain were recorded during 5 weeks lactation. In addition, to be able to assess importance of sow behaviour on piglet growth more definitely, individual within-lactation repeatability of sow behaviour was also evaluated. Average piglet daily weight gain (ADG) and within-litter variation in weight gain during lactation were recorded by weighing the piglets of 21 individually penned, unrestrained Yorkshire sows on days 1, 4, 8, 15, 22 postpartum (PP) and at weaning (day 35±2). Nursing behaviour and sternal recumbency from five 24h periods (days 3, 6, 13, 20 and 30 postpartum) were described as frequency of successful nursings (SFREQ), frequency of unsuccessful nursings (USFREQ), total duration of all nursings (TOTDUR), percentage of nursings terminated by the sow (%SOW), average duration of sow-terminated nursings (SOWDUR) and percentage of observations when the sow was lying sternally (%STERN). With proceeding lactation, the only significant change in SFREQ was an increase on day 6. USFREQ increased to day 13, and then decreased towards the end of lactation. TOTDUR began decreasing after day 13, while SOWDUR decreased already after day 3. %SOW and %STERN both increased with proceeding lactation. All behavioural measures showed within-sow repeatability (first-order autoregression coefficient (AR(1))=0.39–0.73). Average piglet weight gain (ADG) was influenced positively by SFREQ ( P =0.02), while none of the other behavioural variables affected ADG. The effect of SFREQ on ADG was similar throughout lactation, the model estimated a 5.12g increase in ADG with one more successful nursing per 24h. Within-litter variation was not influenced by any of the selected variables. The results indicate that (i) nursing behaviour changes during lactation, according to a pattern suggesting an ongoing weaning process; (ii) sow behaviour is repeatable within-sow and within-lactation; (iii) a high frequency of successful nursings affects piglet growth positively also in sows that are not experimentally manipulated, and throughout the full course of lactation.

Metabolic state of the sow, nursing behaviour and milk production

Twenty-one sows were studied to investigate if lactating sow metabolism relates to behaviour and piglet performance. Blood samples from days 7 and 21 were analysed for NEFA, urea, glucose, insulin, somatostatin and prolactin. The behaviour parameters obtained from 24-h video recordings (days 6 and 20) included: successful and unsuccessful nursing frequency, total nursing duration, percentage and average duration of nursings terminated by the sow, and percentage of observations of sow sternal recumbency. Weight loss and catabolic state of the sows increased from day 7 to day 21; NEFA and post-feeding urea were higher and pre-feeding glucose and insulin lower on day 21. NEFA correlated strongly with sow weight loss during week 1. Prolactin correlated positively with the amount of udder stimulation in week 1 and insulin positively (week 1) or negatively (week 3) with a high incidence of massage-avoiding behaviour. High sow weight loss and NEFA during week 1 were associated with low piglet mortality. High piglet growth correlated positively with sow weight loss during week 3. We conclude that (i) catabolism increases during the first 3 weeks of lactation, (ii) there is some association between sow metabolism and behaviour and (iii) the ability of a sow to turn catabolic soon after parturition decreases piglet mortality risk.

Associative effects on total tract digestibility in horses fed different ratios of grass hay and whole oats

Abstract The present experiment was performed according to a 4×4 Latin square design with diets composed of (on dry matter (DM) basis) the following ratios of grass hay to whole oats: 100:0 (O0), 80:20 (O20), 60:40 (O40) and 40:60 (O60). Four mature Standardbred geldings weighing 493 (S.D. 34) kg were used. The digestibility of DM, organic matter and energy (dE) increased in a curvilinear pattern with the increasing inclusion levels of oats. It is suggested that this was a reflection of the significantly lowered digestibility of nutrients and particularly of fibrous components for the O60 diet as compared with the other three rations, thus resulting in negative associative effects between grass hay and oats. On the basis of the present data, and excluding the results of the O60 diet, the digestibility of dE of oats was estimated to be 75%. As an expression of the associative effect at the O60 level, the dE of the total diet was estimated to be 58%, as compared with 63% when estimated on the oats value of 75% and the O0 diet, resulting in a depression of dE of the total diet by 8%, mainly affecting the utilization of fibrous components. Urinary energy losses decreased with increasing level of oats.

Sow activity level, frequency of standing-to-lying posture changes and anti-crushing behaviour—within sow-repeatability and interactions with nursing behaviour and piglet performance

Abstract Starvation and crushing by the sow are the two main causes of piglet mortality prior to weaning, thus it is obvious that the behaviour of the sow influences piglet survival. In order to increase the understanding of the behavioural mechanisms influencing piglet performance, we recorded undisturbed general activity (standing or walking), frequency of standing-to-lying posture changes (standing-to-lying) and carefulness at standing-to-lying during a 5-week lactation for 24 Yorkshire sows. Carefulness was estimated using four components of sow anti-crushing behaviour (rooting or sniffing piglet prior to standing-to-lying, careful standing-to-lying and no piglets in danger zone at standing-to-lying). We investigated the changes in and consistency of these behaviours throughout lactation, as well as the associations between different aspects of behaviour. Secondly, we examined whether sow activity level and frequency of standing-to-lying were related to nursing behaviour, sow body resource mobilisation (measured as blood concentration of non-esterified fatty-acids (NEFA)) and piglet growth. In addition, we grouped the sows according to litter mortality and according to whether they had crushed any piglets or not and determined if these groups differed in the above mentioned behaviour patterns. Both the activity level and frequency of standing-to-lying of sows increased and had high within-sow repeatability throughout the 5-week period. Carefulness at standing-to-lying did not change significantly over lactation. The variable showed very low within-sow repeatability and only one aspect of carefulness (rooting of the floor) decreased in the later stages of lactation. No significant associations were found between activity level and frequency of standing-to-lying on the one hand, and nursing behaviour or growth of the piglets on the other, except for a positive correlation between frequency of standing-to-lying and observations of the sow lying on her udder. Sows with low mortality (less than two dead piglets) in their litters were more active on day 3 postpartum (pp) than sows with high mortality. The difference was especially clear when comparing sows with or without any crushed piglets in their litters. Sows with no crushed piglets also showed a higher incidence of rooting the floor on day 3 than sows with at least one crushed piglet. Activity level of the sow seems to be an individual characteristic that has possibly been decreased by selection for large and docile animals, suited to intensive production systems. Activity level and amount of rooting performed at standing-to-lying appear to be important aspects of good maternal characteristics. Our results encourage studies of selection for enhanced piglet survival via improved maternal abilities.

Energy-intake and activity risk factors for owner-perceived obesity in a defined population of Swedish dogs.

Our main objective was to obtain baseline data on daily metabolisable energy (ME) intake, activity, and risk factors for obesity in a population of 460 privately owned Swedish dogs in 1999. A previously validated mail-and-telephone questionnaire was used (Sallander et al., 2001a). The dogs were of 124 breeds, 1-3 years old, and had body weights (BW) between 1 and 75kg. The ME intakes of this population could be described with the equation ME(intake) (kilojoules, kJ/d)=554BW(0.66) (r(sp)=0.73, P=0.0001). The energy intake originating from commercial foods was 79% (median, range 45-97). Table foods generally had a higher fat content (median 13g/megajoule, MJ, range 1-122) than commercial foods (median 8g/MJ, range 2-18; P=0.0001). The median energy density was 1603kJ/100g (median; range 1106-2105). Almost all (97%) dogs were taken for walks, and there was a significant difference between the duration of the walks during weekdays and weekends (medians 60 and 90min/d, respectively, P=0.006). Sixty percent of all dogs were trained in activities such as obedience (31%), hunting (27%) or tracking (18%) for a median of 35min/d (range 1-146). The final regression model for obesity included the factors sex, appetite and feeding a home-made diet/table foods. Dogs that were perceived to have good or very good appetite had 3.42-fold greater odds for obesity than individuals with bad or very bad appetite (95% CI 1.19-9.80; P=0.022). Females had 2.17-fold greater odds of being obese than males did (95% CI 1.30-3.70; P=0.003). Also, dogs fed table foods or home-made diets had 2.06-fold greater odds of obesity than those that were not given these food items (95% CI 0.97-4.35; P=0.050).

Oxytocin, prolactin and somatostatin in lactating sows: associations with mobilisation of body resources and maternal behaviour

Abstract The aim of the present study was to investigate how oxytocin, prolactin and somatostatin during nursings relate to maternal characteristics of sows. Undisturbed nursing behaviour and sow–piglet nasal contacts of 21 lactating sows were recorded on day 13 of lactation, and hormonal status was assessed during three successful nursings on day 14. Piglet and litter growth (days 8–15), sow weight loss (days 1–15) and catabolic state (measured as NEFA on day 7), as well as number of successful nursings on day 13 were used as measures of mobilisation of sow body resources. Nasal contacts and sow behaviour facilitating udder massage were used as measures of positive piglet-directed behaviours. Concentrations of oxytocin were higher, those of prolactin lower and those of somatostatin similar during nursings compared to samples taken 15 min after nursing. Oxytocin peaked during most nursings and prolactin increased gradually after nursings. Non-nursing oxytocin values were positively correlated with the proportion of sow-terminated nursings but not with other measures of piglet-directed behaviour. Non-nursing oxytocin concentrations were positively correlated with piglet weight gain and concentrations of oxytocin during nursings were correlated with NEFA and sow weight loss. Our results indicate that oxytocin might have more than merely an all-or-nothing function in triggering milk ejection. Oxytocin seems to be quantitatively related to efficiency of milk production, although the present study design does not allow for speculation on causal relationships.

Protein Evaluation of Mixed Diets

The procedure suggested by FAO/WHO to evaluate the protein quality of mixed diets has been tested using vegetable and vegetable-animal protein diets. Chemical scores were calculated and protein digestibilities were compared in human adult, growing pigs and rats. Pigs were studied as alternatives to rats in the protein evaluation of human diets. The results showed that the choice of the samples to calculate the chemical score is important; that the composition of the samples for biological evaluations must be considered in order to avoid experimental problems, and that values for true protein digestibility in human subjects, pigs and rats are in agreement, and further studies of growing pigs as an experimental model are suggested. Minor differences in protein quality of the two diets were demonstrated.

Reproductive endocrinology and postweaning performance in the multiparous sow. Part 2. Influence of nursing behavior

The reason for variation in postweaning reproductive performance among multiparous sows is to a large extent unknown. In the present study, the influence of nursing behavior was explored. Blood samples were collected during lactation and after weaning from 18 multiparous sows for cortisol, LH, estradiol-17beta (E2), and progesterone analysis. Sow and piglet behavior was videotaped. The sows were fed according to litter size and slaughtered after the second postweaning estrus. The sows were divided into two groups based on average values for the different behavioral parameters. Sows with a long average nursing duration (long group) had lower average and basal LH levels on Day 14 and 21 of lactation as compared to the sows having a short average nursing duration (short group). In the long group, concentrations of E2 were lower the day after weaning, but on Day 15 and 21 of lactation no differences were noted between the two groups. Postweaning performance seemed impaired in the long group, though, differences were not significant. The sows in the long group were heavier and tended to lose less weight during lactation. To conclude, nursing duration seems to influence the extent to which reproductive functions are inhibited during lactation.

Feeding patterns and dietary intake in a random sample of a Swedish population of insured-dogs.

We used a validated mail and telephone questionnaire to investigate baseline data on feeding patterns and dietary intake in a random sample of 460 Swedish dogs. In 1999, purebred individuals 1-3 years old in the largest insurance database of Sweden completed the study. Most dogs were fed restricted amounts twice a day, and the feeding patterns seldom were changed after the age of 6 months. Typically, the main constituent of the meals was dry food [representing 69% of dry matter (DM)]. Four out of five dogs also got foods that (in descending order of the amount of energy provided) consisted of vegetable oil, meat, sour milk, bread, potatoes, pasta, lard/tallow, sausage, cheese, rice and fish. The heavier the dog (kg), the more dry dog food was consumed (g DM/d). The dry-food intakes (g DM/d) increased linearly with body weight (BW, in kg): intake=-15.3+8.33 BW (P=0.0001; r=0.998), a clear relationship that was not observed for other commercial foods. The non-commercial part of the diet had higher fat (13 and 8 g/megajoule, MJ, respectively; P=0.00001) and lower protein (12 and 16 g/MJ, respectively; P=0.00001) compared to the commercial part of the diet. Six out of ten dogs were given treats, and one-fourth was given vitamin/mineral supplements (most commonly daily). Most dogs consumed diets that were nutritionally balanced. No dogs in the study consumed diets that supplied lower amounts of protein than recommended by the NRC (2006). Only two individuals (<1%) were given total diets that were lower than the nutrient profiles in fat. Few dogs consumed total diets that were lower than recommended by the NRC (2006) in calcium, phosphorus, and vitamins A, D and E (2, 1, 3, 5, and 3% of the individuals, respectively). A few individuals consumed higher levels of vitamins A and D (<1 and 4%, respectively) than recommended. Diets that deviated from recommended levels were those consisting of only table foods with no supplements (too-low in vitamins and minerals) or commercial foods+no table foods supplied with extra vitamin and mineral supplements (too-high in vitamins and minerals).