Dorsal Fat Thickness Research Articles

Research on Contactless Detection of Sow Backfat Thickness Based on Segmented Images with Feature Visualization

Aiming to address the problem that the existing methods for detecting sow backfat thickness are stressful, costly, and cannot detect in real time, this paper proposes a non-contact detection method for sow backfat with a residual network based on image segmentation using the feature visualization of neural networks. In this paper, removing the irrelevant information of the image to improve the accuracy of the sow backfat thickness detection model is proposed. The irrelevant features in the corresponding image of the feature map are found to have the same high brightness as the relevant feature regions using feature visualization. An image segmentation algorithm is then used to separate the relevant feature image regions, and the model performance before and after image segmentation is compared to verify the feasibility of this method. In order to verify the generalization ability of the model, five datasets were randomly divided, and the test results show that the coefficients of determination (R2) of the five groups were above 0.89, with a mean value of 0.91, and the mean absolute error (MAE) values were below 0.66 mm, with a mean value of 0.54 mm, indicating that the model has high detection accuracy and strong robustness. In order to explain the high accuracy of the backfat thickness detection model and to increase the credibility of the application of the detection model, using feature visualization, the irrelevant features and related features of the sow back images extracted by the residual network were statistically analyzed, which were the characteristics of the hip edge, the area near the body height point, the area near the backfat thickness measurement point (P2), and the lateral contour edge. The first three points align with the previous research on sow backfat, thus explaining the phenomenon of the high accuracy of the detection model. At the same time, the side contour edge features were found to be effective for predicting the thickness of the back. In order to explore the influence of irrelevant features on the accuracy of the model, UNet was used to segment the image area corresponding to the irrelevant features and obtain the sow contour image, which was used to construct a dorsal fat thickness detection model. The R2 results of the model were above 0.91, with a mean value of 0.94, and the MAE was below 0.65 mm, with a mean value of 0.44 mm. Compared to the test results of the model before segmentation, the average R2 of the model after segmentation increased by 3.3%, and the average MAE decreased by 18.5%, indicating that irrelevant features will reduce the detection accuracy of the model, which can provide a reference for farmers to dynamically monitor the backfat of sows and accurately manage their farms.

Short-term responses of meat ewes facing an acute nutritional challenge in early-mid lactation.

Simulating a consequence of a climate change event on feed availability, responses of Mediterranean meat ewes facing an acute undernutritional challenge (CHA; i.e., fed only low nutritional value cereal straw) were evaluated at a sensitive physiological stage (i.e., early suckling). Forty Romane ewes were chosen at early-mid pregnancy (around 2 mo) according to parity (20 primiparous, PRIM; 20 multiparous, MULT); feed efficiency genetic line of their sires (residual feed intake [RFI]; efficient, RFI-, n = 10 per parity; inefficient, RFI+, n = 10 per parity); litter size (i.e., bearing twins, diagnosed by ultrasonography); body weight (BW, kg) and body condition score (BCS) (initial BW and BCS [mean ± SD]: 51.6 ± 7.41kg; 2.5 ± 0.20, respectively; representing flock' averages per parity). Effects on dry matter intake (DMI), ewes' BW and BCS, subcutaneous dorsal fat thickness (DFT), energy metabolism (plasma non-esterified fatty acids [NEFA], β-hydroxybutyrate (β-OHB), glucose, urea, triiodothyronine [T3]), and lambs' growth (BW and average daily gain [ADG]; g/d) were examined before, during and after CHA. Individuals' profiles of the response-recovery to CHA were described using a piecewise mixed-effects model. The fixed effect of parity and genetic line and the random effect of individual (ewe) were considered. A linear mixed-effects model was fitted to explore the effects on lambs' growth. The 2-d straw-only CHA had significant effects on most of the recorded parameters. Meaningful drops and recoveries were observed on ewes' DMI, BW, and DFT with effect on postchallenge levels. BW, BCS, DFT, or DMI were also affected by parity (MULT > PRIM) but not by genetic line. Plasma NEFA, β-OHB, glucose, urea, and T3 responded well to CHA with drops in T3, urea, and glucose levels, whereas NEFA and β-OHB significantly increased after CHA. MULT ewes presented sharper β-OHB recovery from CHA than PRIM (P ≤ 0.05). With this study, we provide tangible and necessary data for an emerging field of research. Our results give new insights into how such a short and abrupt CHA affects some key zootechnical and physiological parameters, and to what extent the impacts of CHA and the ewes' response-recovery are influenced. It also revealed potential between-individual differences in the adaptive capacities of ewes, which require further exploration.

Combining sheep and beef cattle in a pasture-based system minorly influenced muscle and fat colour and dorsal fat firmness but increased fat skatole content in lambs.

A recent long-term system-level experiment, using grassland-based organic systems established as separate farmlets, showed that combining sheep and beef cattle within a mixed (MIX) system promoted self-sufficient production of grass-fed meat and improved economic and environmental performance in the sheep enterprise compared to a sheep-only (SH) system. In the present study, we used all male lambs produced over the first year in this experiment to evaluate the effect of this farming practice on some lamb carcass and meat sensory quality traits. Lambing took place at the end of February and lambs were pasture-fed from 1month of age on average until slaughter, unless they were not ready for slaughter at 3-4weeks before the start of the mating period in October, in which case they were finished indoors on a concentrate-based diet. All MIX lambs (n=33) were finished at pasture. One SH lamb (out of a total of 85) had to be finished indoors with a concentrate-based diet. MIX lambs had a higher growth rate than SH lambs (P<0.001), resulting in a lower lamb age at slaughter in MIX than in SH (150 vs 173days, P<0.001). Carcass weight and degree of fatness, kidney fat weight and dorsal fat thickness did not differ between systems. Kidney fat skatole concentration was higher in MIX than in SH (median value reaching 0.15µg/g liquid fat and 0.11µg/g liquid fat in MIX and SH, respectively, P<0.05). This was most likely due to MIX lambs being slaughtered at a younger age and therefore eating younger grass. There were minor differences between MIX and SH lambs in dorsal fat firmness and in colour coordinates of longissimus thoracis et lumborum muscle. We conclude that while combining sheep and beef cattle within a mixed system offers advantages in terms of self-sufficient production of grass-fed meat and system economic and environmental performance, it could come at a cost to lamb flavour.

Liposuction to improve the dorsocervical fat pad in esthetic need: Anatomical study and clinical case series.

Patients are undergoing surgery to relieve the prominent dorsocervical fat pad because of their esthetic needs. To determine their clinical needs, it is necessary to research the clinic, radiography, and anatomy of dorsocervical fat pad. The occipital fat thickness, dorsal fat thickness, and the length, width, and thickness of the dorsocervical fat were measured through MRI imaging. Body projection position were recorded. The correlation between the body mass index and dorsocervical hump was analyzed. Anatomical and histological studies of cadavers with a dorsocervical hump were performed. The liposuction for dorsocervical fat pad was introduced and patients were followed up. In measurement, the MRI imaging of 109 patients were evaluated. The average length, width, and thickness of the dorsocervical fat pad were 114.47, 89.24, and 23.46 mm, respectively, and it is commonly located from the 3rd cervical vertebra to the 3rd thoracic vertebra. The average dorsocervical ratio was 151%. 43.1% patients had a dorsocervical hump. Based on the protrusion degree, the dorsocervical fat pad was classified into three types. The dorsocervical hump severity had a low correlation with obesity. In anatomy, 4 cadavers were dissected. The histological staining indicated that two layers of fat pad constituted a dorsocervical fat pad. As for treatment, 34 patients underwent liposuction to improve the dorsocervical contour, all of them reported satisfactory outcome. The histological manifestations and morphological measurement of dorsocervical fat pad is researched. Besides, liposuction was applied in 34 patients with dorsocervical hump, and had received satisfied outcome.

Performance and carcass characteristics of lambs fed diets supplemented with different levels of Saccharomyces cerevisiae

The objective of this study was to evaluate the productive performance, apparent digestibility, and carcass and longissimus dorsi muscle characteristics of lambs fed diets supplemented with four levels of Saccharomyces cerevisiae. Thirty-two male Hampshire lambs (25.82±1.95 kg body weight) were distributed in four treatments: basal diet (20:80, forage:concentrate), and the inclusion of 0, 3, 5, and 10 g animal−1 d−1Saccharomyces cerevisiae. The variables evaluated were dry matter intake, daily weight gain, feed conversion, apparent digestibility, dorsal fat thickness, longissimus [...]

A meta-analysis on the effect of the feeding type and production system on the carcase quality of lambs

This meta-analysis aims to identify if there are differences between the weight of lamb carcases and their main characteristics according to the production systems and type of feeding around the word. Lambs finished on feeding supplement (with or without supplement) and production system (feed-lot or free-range) were analysed. Data from 21 controlled studies were used, the variables of interest in the meta-analysis include: initial body weight (IBW, kg), final body weight (FBW, kg), hot carcase weight (HCW, kg), cold carcase weight (CCW, kg), area of longissimus dorsi (ALd, cm2), subcutaneous dorsal fat thickness (SFT, mm) and slaughter weight (kg). The high heterogeneity (>98%) found in this study may be due to many factors (breed, climate, age and management). Furthermore, the number of animals allocated for each treatment and the lack of repetitions make it difficult to correctly understand the effect of feeding and production system on the lamb meat. Lambs finished in a feedlot or with supplementation under extensive systems exhibit faster growth rates, achieve target weights quicker, and produce heavier carcase weights when compared to grazing lambs.HighlightsLambs finished in a feedlot or with supplementation under extensive systems exhibit faster growth rates compared to grazing lambs.Lambs finished in a feedlot or with supplementation under extensive systems achieve target weights quicker compared to grazing lambs.Finishing lambs on high-quality pasture can produce satisfactory growth rates without compromising characteristics of carcase.

Influencia del sistema de producción en la calidad de la canal de cerdos de raza Bísara

La utilización de razas locales en sistemas de producción alternativos presenta una serie de ventajas, como la gestión medioambiental, la biodiversidad y la producción agrícola sostenible orientada hacia un mercado de productos de calidad diferenciada, especialmente en áreas desfavorecidas. En este trabajo se estudió la influencia de dos sistemas de producción en la calidad de la canal de cerdos de raza Bísara. La alimentación recibida fue igual en ambos casos. En la fase de crecimiento (98 días) se alimentaron con pienso compuesto comercial, mientras que durante el acabado se les administró pienso compuesto y harina de maíz. Se recogieron datos de peso vivo y canal después de 24h a 4ºC y se calculó el rendimiento de la canal. Se realizaron medidas morfométricas lineales de la media canal derecha, tras 24h post-mortem. El espesor de la grasa dorsal se midió a nivel de la 1ª costilla, la última costilla, en el músculo gluteus medius en el área más espesa de grasa (extremo craneal) y en la de inferior espesura. Teniendo en cuenta los resultados obtenidos, no se observan diferencias significativas en ninguno de los parámetros analizados. El peso de la canal fría (94,23±7,55 kg) y el rendimiento (75,51±1,48%) así como las medidas morfométricas mostraron valores prácticamente coincidentes entre ambos tipos de sistemas de producción. Tampoco se observaron diferencias en el espesor de la grasa dorsal. Las cuatro medidas indican un grado elevado y homogéneo de grasa dorsal, característica frecuentemente constatada en razas de cerdos no mejoradas (razas locales) existentes en todo el mundo.

Variations in the Temperature-Humidity Index and Dorsal Fat Thickness during the Last Trimester of Gestation and Early Postpartum Period Affect Fertility ofBos indicusCows in the Tropics

In order to measure the influence of the temperature-humidity index (THI) and the variation of fat thickness on reproductive performance, ninety-two Bos indicus cows kept under grazing conditions were used in two farms in Veracruz (Mexico) and Puntarenas (Costa Rica). THI was calculated with the average environmental temperature and relative humidity. Measurements of fat thickness (FAT) were taken two weeks apart from the last trimester of gestation to approximately 80 days postpartum (dpp). Natural breeding was used in both farms. Time to conception was calculated based on the interval from days at risk to conception (DRC), which had to be at least 28 dpp. THI was between 65.4 ± 2.9 and 73.2 ± 1.5 in Veracruz and 75.4 ± 0.26 and 76.5 ± 0.55 in Puntarenas. Variations in THI were observed in Puntarenas whereas in Veracruz THI variations were more prominent. In Veracruz, loss of fat during the last trimester of gestation was on average 8.5%, whereas in the postpartum period it was 18.4% (P = 0.042). In Puntarenas, the variation in the last trimester of gestation was on average 18.7% and in the postpartum period was 10.5% (P = 0.012). The relative change in FAT in Veracruz was 36.7%, and in Puntarenas it was 29.3%. Overall, 60% of the cows became pregnant. FAT decreased the interval of DRC (R2=0.06; P=0.033) with a high relationship (R2=0.76; P< 0.0001) between THI and time to conception, in both farms. In conclusion, THI levels influence the reproductive performance in early postpartum period affecting DRC.

Body size, carcass and meat quality of three commercial beef categories of ‘Serrana de Teruel’ breed

The aim of this study was to analyse three commercial beef categories of the ‘Serrana de Teruel breed’ to define the appropriate commercial option. Twenty ‘Serrana de Teruel’ male calves at 9 months were assigned to the commercial beef categories (young bulls, bulls and steers), slaughtered at 12, 22 and 22 months of age, respectively. The in vivo ultrasound backfat thickness was greater than the dorsal fat thickness, and the young bulls and steers had a similar fat thickness, that was greater than the bulls in both areas. The slaughter weight and cold carcass weight were significantly different between the commercial categories. However, the differences were not sufficient to modify the dressing percentage, carcass conformation and fatness degree between the young bulls and bulls. The maximum stress of the muscle at 7 d of ageing was lower in the steers than in the young bulls and bulls. In general, the lightness of the meat in the bulls was lower than that in the young bulls and steers. The subcutaneous fat of the bull carcasses had a vivid colour and stored more carotenoids than that of the young bulls and steers. Hence, bulls produced heavier and better conformed carcasses with more edible meat and less fat than the other categories. However, steers are recommended to produce large carcasses with more trim and cover fat than the other categories. Finally, it seems that bulls are the most suitable commercial category to ‘Serrana de Teruel’ breed.

Quality of Carcass and Fat of Pigs Receiving Diets with Sorghum, Canola Expeller and Peas

In order to determine the effect on carcass and fat characteristics of replacing maize and soybean meal (SM) with low tannin sorghum (LTS) and canola expeller (CE), respectively, 42 pig carcasses from seven feeding systems were studied: T1, Maize/SM; T2: LTS/SM grain; T3: LTS/SM wet grain silo; T4: Maize/wet grain sorghum MT/SM silo; T5: Maize/sorghum grain MT/SM; T6: Maize/(CE/peas); T7: LTS grain/(CE/peas). The pigs were slaughtered with an average live weight of 108 ± 2 kg. Carcass length, dorsal fat thickness, loin eye area, meat/fat ratio in steak, intramuscular fat content, and lipid profile were evaluated. There were no differences between treatments in carcass characteristics. Intramuscular fat content was higher in T4 pigs. Diets with CE substituting SM presented higher content ofω3 acids. It is concluded that the replacement of maize with LTS in diets for fattening pigs does not change the composition of carcasses nor the lipid profile of the dorsal fat. The replacement of SM with a mixture of CE and peas does not affect carcass characteristics but changes the lipid profile, with an increase of ω3.

Meat quality and carcass characteristics of Merino Precoce suckling lambs raised under confinement in the Mediterranean semi-humid dryland of Central Chile

Twenty-eight Merino Precoce suckling lambs raised under confinement in the Mediterranean semi-humid dryland of Central Chile were studied to evaluate meat quality and major carcass characteristics. Animals were grouped by slaughter weight (10 and 15 kg) and sex (7 males and 7 females in each weight group). The average commercial and true dressing percentages were 53 and 55%, the average ribeye area was 11.7 cm2, and the average dorsal fat thickness was 1.5 mm. The largest retail yields were those of the leg and shoulder, at 38 and 22%, respectively. The tissue composition of the leg was 58% muscle, 23% bone, 12% fat, 3.6% residues, and 3% shrink loss. The tissue composition of the shoulder was 57% muscle, 23% bone, 11% fat, 3.7% residues and 3.2% shrink loss. The average chemical composition of the fresh meat was 67% moisture, 19% protein, 13% ether extract, and 1.3% ash. Sensory panel evaluation indicated that almost all the sensory characteristics were within the ideal range, and the acceptability panel evaluation indicated that 15 kg lambs produced the most acceptable meat. Slaughter weight had the most significant effect on carcass and meat quality. These results confirm that Merino Precoce suckling lambs yield high-quality carcasses and highly acceptable meat.

Transcriptome analysis to identify differential gene expression affecting meat quality in heavy Italian pigs

Suppressive subtractive hybridization (SSH) was used to analyse the muscle transcriptome and identify genes affecting meat quality within an Italian pig population of Large White and Landrace purebred individuals. Seven phenotypes were recorded at slaughter: dorsal fat thickness, ham fat thickness, ham fat coverage, muscle compactness, marbling, meat colour and colour uniformity. Two subtractive libraries were created from longissimus dorsi tissue of selected pigs with extreme phenotypes for meat quality. Eighty-four differentially expressed ESTs were identified, which showed homology to expressed pig sequences and/or to genomic pig sequences produced within the pig genome project. Sixty-eight sequences were mapped on the pig genome, and most of these sequences co-localized with the same chromosomal positions as QTLs that have been previously identified for meat quality. Thirty sequences, including eight matching known genes previously related to muscle metabolic pathways, were selected to statistically validate their differential expression. Association analysis and t-test results indicated that 28 ESTs of the 30 analysed were associated with phenotypes investigated here and have significant differential expression levels (P≤ 0.05) between the two tails of the phenotypic distribution.

Effects of two different diets on carcass and meat quality traits of Chato Murciano pigs

Abstract. A total of 40 castrated male pigs of the Spanish autochthonous Chato Murciano breed were used for this study to evaluate the influence of two diets. One group of 20 pigs was fed with a high protein/low fat (HP/LF) diet and slaughtered with life weight (LW) of 125.03 kg. The other group of 20 pigs was fed with a low protein/high fat (LP/HF) diet and slaughtered with 121.91 kg LW. The effects of diet on carcass and meat quality traits were studied. Meat samples were taken from the longissimus lumbar (LL) muscle. The HP/LF diet produced a faster growing rate and higher daily weight gain, and measurements in the LL muscle showed higher values of ultimate pH (pHu), colour parameters, and higher content in Ca, Mg, Zn, K and Na. The LP/HF diet led to higher values of Fe and Cu. The difference in the LL muscle intramuscular fat (IMF) levels was noteworthy, with values of 3.21 % in the HP/LF group and 11.00 % in the LP/HF group; however, the dorsal fat thickness measurements showed no differences. The fatty acid composition of the IMF was 42.43 and 42.29 % of saturated fatty acids (SFA), 50.34 and 51.35 % of monounsaturated fatty acids (MUFA) and 7.20 and 6.24 % of polyunsaturated fatty acids (PUFA) for the HP/LF group and LP/HF group respectively, with only statistically significant differences in the MUFA levels (P≤0.05).

Carcass and meat quality traits of the Chato Murciano pig slaughtered at different weights

In order to evaluate the effect of slaughter weight and rearing system on the Chato Murciano pig carcass and meat quality traits, a total of 71 castrated male pigs were used. Forty-one pigs were reared in an outdoor system, divided in one heavy group (CHOHW) with an average live weight of 132.05 kg, and a second group with lower weights (CHOLW, 115.7 kg average). Simultaneously, 30 pigs were reared indoors and divided into one heavy group (CHIHW) with an average live weight of 144.3 kg, and a second group with lower weights (CHILW, 117.6 kg average). Heavier pigs showed higher values for several carcass parameters (hot carcass weight, carcass length, maximum perimeter of the ham, hand length, leg length, ham length, wrist perimeter) and meat cuts, higher Dorsal Fat Thickness (DFT) and Intramuscular Fat (IMF) levels, but no difference was found in the hot carcass yields (HCY). Differences in the colour parameters and several minerals (Ca, Mg, K and Na) were also due to the different slaughter weights. The rearing system had an influence on the HCY (it is higher in the outdoor system), on many carcass parameters, on meat the ultimate pH (it is higher for animals reared indoors) and on colour (this is variable). It also affected the levels of many minerals with the levels of Mg, P and K being higher for animals reared outdoors, whereas the Fe, Cu and Zn content were higher in the animals reared indoors. DFT and IMF levels were not influenced by the rearing system.

Effect of a moderate feed restriction on subsequent growth and body composition in pigs raised under high environmental temperatures

The experiment was conducted to assess the influence of a moderate feed restriction during the growth period on overall performance, corporal traits and fatty acid composition in pig backfat in pigs raised under high environmetal temperatures. A hundred Large White x (Large White x Landrace) barrows with an average initial weight of 34.5 kg were randomly distributed, in pens (10 pigs per pen). Fifty pigs were fed ad libitum for 36 days (AL pigs) and another fifty were restricted by 25% of their ad libitum consumption during the same period (R pigs). During the subsequent re-feeding period (64 days) all pigs were fed ad libitum. The only diet used contained 13.4 MJ ME kg -1 , 17% crude protein and 1.3% lysine. The minimum, maximum and mean average temperatures recorded during the feed restriction and post-restriction periods were, oC: 21.5 ± 1.2, 28.6 ± 1.3 and 25.0 ± 1.1, and 22.6 ± 0.9, 31.2 ± 1.0 and 26.9 ± 0.9, respectively. Considering the whole study period, the average daily gain and average daily feed intake were higher (P 0.05) (2.95 vs 2.95 kg . kg -1 ). At the end of experiment, no differences for dorsal fat thickness and area and for longissimus dorsi muscle depth, width and area, measured at site of the last rib by means of a real-time ultrasound device, were found between experimental groups. The linolenic acid proportions of the subcutaneous fat outer and inner layer were higher in AL than in R pigs (P<0.05), while palmitic and saturated fatty acids total proportions of the subcutaneous fat inner layer were higher in R than in AL pigs (P<0.05).

Composition and estimation of intramuscular and subcutaneous fatty acid composition in Spanish young bulls

Sixty Pirenaica yearling intact bulls were raised and slaughtered at 519 ± 50 kg live weight and 371 ± 18 days of age. Fatty acid composition of intramuscular lipids in longissimus dorsi muscle and subcutaneous fat were determined by capillary gas chromatography. Carcass conformation and fatness, carcass weight, ether extractable intramuscular fat percentage, marbling, dorsal fat thickness, and ultrasonic parameters were recorded to study the relationship between these traits and fatty acid profile. Lipids of subcutaneous adipose tissue had higher monounsaturated fatty acids (MUFA) percentage (49% vs. 33%) but lower saturated fatty acids (SFA) (51% vs. 46%) and polyunsaturated fatty acids (PUFA) (16% vs. 5%) percentages than intramuscular fat depots ( p < 0.001). Fatter carcasses had higher MUFA percentage and lower PUFA percentage ( p < 0.01) in intramuscular fat. Carcass weight and conformation would contribute to explain the fatty acid profile of subcutaneous fat ( p < 0.05). Ultrasound readings reflected the effect of fatness on fat composition.

Fatty acid composition and carcass characteristics of growing lambs fed diets containing palm oil supplements

Thirty 45-day-old male Ojalada lambs were used to investigate the effect of palm oil (as such or in the form of calcium soap) on carcass characteristics and fat composition. Dietary palm oil did not significantly affect dorsal fat thickness, carcass fatness or carcass conformation. The palm oil supplement did not affect C16:0 levels in intramuscular and subcutaneous fat, but did increase the percentage of C16:0 and reduce PUFA and MUFA content in internal fat depots. Supplementation with palm oil in the form of calcium soap did not cause significant differences in the composition of intramuscular fat. Subcutaneous and perirenal fat of lambs fed treatments including palm oil as such contained higher levels of some saturated fatty acids than that of those fed fat in the form of calcium soap. Mesenteric fat of lambs that received calcium soap had less % C18:1 and more % C18:3 than that of those given palm oil.

Characteristics of the carcass and meat of the Chato Murciano pig

The study of meat quality, using the autochthonous pig breed from the region of Murcia (Spain) Chato Murciano as the raw material, is the logical consequence of the demand of the participating social sectors, from the producer to the consumer. The recent interest, both public and private, which has been taken in the recovery of this breed means that we can count on a distinguished product, in need of adequate studies which will allow it to compete with other breeds in the market. We have studied a range of qualitative and quantitative parameters of the carcass and meat in 31 animals of the pig breed of an average age of 10 months. Some of the mean results obtained are DFT2 (dorsal fat thickness on the last rib): 3.09±0.68 cm; perimeter of the ham: 73.94±4.37 cm; and length of the ham: 37.16±3.12 cm. The evolution of the pH in the carcass is that of pigs which do not produce PSE (pale, soft, exudative) meat.

Studies on carcass quality traits in two populations of Coho salmon ( Oncorhynchus kisutch): phenotypic and genetic parameters

Phenotypic and genetic parameter estimates of carcass quality traits were obtained from two pedigreed populations, termed even and odd, of a Coho salmon breeding program. Carcass quality data from 3444 fish (1802 male and 1642 female), harvested at 21 months of age, were analyzed. In both populations, significant sex effects were found for body weight (3487–3354 g, male and female, respectively), total visceral weight (448–397 g), gonad weight (239–166 g), abdominal fat percentage (8.9–10%), fillet percentage (56.5–59.3%), total width of steak (8.2–8.0 cm), area of cutlet (231–217 cm 3), but not for abdominal fat weight (40.8–40.8 g), total fillet weight (2284–2263 g), texture of flesh (1.47–1.46 Kg) and fat content of flesh (18.0–18.1%). Less consistent significant sex effects were found for carcass weight (3086–2944 g, odd population), dressing percentage (86.9–88.8, even population), dorsal fat thickness (1.77–1.71 cm, odd), ventral thickness (1.14–1.17 cm, even) and height of cutlet (5.0–4.7 cm, odd). Heritability estimated for carcass quality traits was medium in magnitude for total visceral weight (0.19–0.33, even and odd), gonad weight (0.26–0.33), abdominal fat weight (0.24–0.35), abdominal fat percentage (0.18–0.26), dressing percentage (0.33–0.23), while estimated heritability was low to medium for body weight (0.13–0.24), carcass weight (0.12–0.22), total fillet weight (0.18, odd), fillet percentage (0.11, odd), dorsal fat thickness (0.09–0.15), ventral thickness (0.05–0.22), total width of steak (0.10–0.30), height of cutlet (0.09–0.24), area of cutlet (0.11–0.33), texture of flesh (0.06–0.09) and fat content of flesh (0.17, even). Estimated genetic correlations ( r g) between various biometrical traits of fish were all positive and ranged from 0.48 to 0.96, while the phenotypic correlations ranged from 0.33 to 0.90. Selection for increased body weight (growth) will produce favourable changes in carcass weight ( r g=0.99), fillet percentage (0.98), and texture (0.30–0.70), but unfavourable changes in dressing percentage (−0.48 to −0.03) and fat content of flesh (0.73). Estimates of genetic correlation were positive and moderate between abdominal fat percentage and fat content of flesh (0.46), and were negative between abdominal fat percentage and carcass weight (−0.45), and between abdominal fat percentage and dressing percentage (−0.44 to −0.11).

Effect on pig performance of feed restriction during the growth period

Two experiments were conducted to determine the compensatory responses of pig to feed restriction during the growth period. Eighty Dalland pigs (40 boars and 40 gilts) and 60 Large White × (Large White × Landrace) barrows were used in two different experiments. They were slaughtered at 97 and 122 kg. During the restriction period, the animals were restricted by 46% and 25% of their ad libitum consumptions in experiment 1 and 2 respectively. The restriction periods lasted 28 and 35 days respectively. Considering the whole study period, in experiment 1 the average daily weight gain and food intake were lower for restricted pigs compared to those fed ad libitum: 762 vs 856 g (P &lt; 0.03) and 2147 vs 2396 g (P &lt; 0.08). However, the feed conversion ratio was no different: 2.83 vs 2.80 g g-1 (P &lt; 0.81). In this experiment, the interaction treatment x sex was not significant in either test. When performance over the total period was examined in experiment 2 (moderate restriction), a stronger trend was seen towards a greater average daily weight gain in groups with restricted access to feed (853 vs 821 g in those fed ad libitum, P &lt; 0.11). No significant differences were observed for average daily feed intake, feed conversion ratio and dorsal fat thickness (measured at the 14th rib by ultrasound) (2638 vs 2635 g, 3.09 vs 3.2 g g-1 and 16,9 vs 16.2 mm respectively).