Nutrition
Research Article
The effect of 1-week feed restriction on performance, digestibility of nutrients and digestive system development in the growing rabbit
- E. Tůmová, Z. Volek, D. Chodová, H. Härtlová, P. Makovický, J. Svobodová, T. A. Ebeid, L. Uhlířová
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- Published online by Cambridge University Press:
- 16 September 2015, pp. 1-9
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A 3 to 4 week feed restriction of about 20% to 25% of the free intake is widely applied in rabbit breeding systems to reduce post-weaning digestive disorders. However, a short intensive feed restriction is described in few studies and can be beneficial for growing rabbits due to a longer re-alimentation period. The aim of this study was to evaluate the effect of ad libitum (AL) and two restriction levels of feeding (50 and 65 g/rabbit per day) applied for 1 week on performance, gastrointestinal morphology and physiological parameters during the restriction and during the re-alimentation period. Rabbits were divided into three experimental groups: AL rabbits were fed AL, R1 rabbits were restricted from 42 to 49 days of age and received 50 g daily (29% of AL) and R2 rabbits were restricted at the same age and were fed 65 g of feed daily (37% of AL). In the 1st week after weaning and in the weeks after restriction, all the groups were fed AL. During the restriction period, daily weight gain (DWG) in R1 significantly dropped to 11% (experiment 1) and 5% (experiment 2) compared with rabbits in the AL group, although they were fed 29% of AL, whereas in the R2 group it decreased to 20% (experiment 1) and 10% (experiment 2). In the week following feed restriction, DWG in the restricted groups increased (P<0.001) to 166% and 148% in R1 and to 128% and 145% in R2. Restricted rabbits in both the experiments reached up to 90% to 93% of the final live weight (70 days) of the AL group. Over the entire experimental period, feed restriction significantly decreased feed intake to 85% to 88% of the AL group; however, the feed conversion ratio was lower (P<0.05) only in experiment 1 (−6% in R1 and −4% in R2). Digestibilities of CP and fat were not significantly higher during the restriction period and during the 1st week of re-alimentation compared with the AL group. Significant interactions between feeding regime and age revealed the shortest large intestine in the AL group at 49 days of age and the longest at 70 days in the AL and R1 groups. Small intestinal villi were significantly higher and the crypts were significantly deeper in the restricted groups. It could be concluded that short intensive feed restriction increased digestible area in the small and large intestines, including the height of villi and depth of crypts, which might be involved in the compensatory growth and defence mechanism.
Effect of purple loosestrife (Lythrum salicaria) diet supplementation in rabbit nutrition on performance, digestibility, health and meat quality
- A. Kovitvadhi, L. Gasco, I. Ferrocino, L. Rotolo, S. Dabbou, V. Malfatto, F. Gai, P. G. Peiretti, M. Falzone, C. Vignolini, L. Cocolin, I. Zoccarato
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- 10 September 2015, pp. 10-18
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In this study, 160 Hycole weaned rabbits (35 days old) were randomly divided into four groups of 40. The rabbits were studied throughout a 54-day experimentation period in order to determine the impact of dietary supplementation from herbs composed of 0.2%, 0.4% dry ground Lythrum salicaria leaves (LS) and 0.3% Cunirel® (CR; a commercial herb mixture containing LS as the main ingredient) on performance, digestibility, health and meat quality. The basal diet was given to the control group. No significant differences were found in performance, 10 rabbits from each group were selected for evaluation regarding apparent digestibility. The rabbits fed the control diet and the diet with the low level of LS had a higher level of CP digestibility than did the animals that were supplemented with the high LS levels and CR (85.7% and 84.9% v. 84.0% and 84.0%, respectively; P<0.05). The ether extract digestibility was lower in the treatment group with 0.4%LS addition and CR as compared with the control group (52.2% and 54.5% v. 62.6%, respectively; P<0.05). The slaughter process was performed on 89-day-old rabbits to study the carcass characteristics, meat quality, blood parameters, caecal contents and gut histology. The total leukocyte counts in the control animals were lower than they were in the rabbits fed 0.2%, 0.4%LS and CR (4.06 v. 8.25, 8.63 and 8.21×109/l, respectively; P<0.05). For caecal fermentation, the caecal contents of the rabbits fed 0.4% of LS, showed higher concentrations of total volatile fatty acid (VFA; 24.1 v. 18.9 mg/kg dry matter (DM); P<0.05) and acetic acid (18.3 v. 14.4 mg/kg DM; P<0.05), but lower ammonia levels (594 v. 892 mg/kg DM; P<0.05) as compared with the control group. PCR-denaturing gradient gel electrophoresis analyses were performed to evaluate the microbial community in hard faeces, collected at days 35, 42, 49, 56, 70 and 89, whereas the caecal contents were taken after slaughtering. The results demonstrated that between the treatment groups, the similarity of the microbial communities was higher as compared with the control group. Moreover, only age was shown to influence microbiota diversity. In conclusion, the results of this study indicated that supplementation of LS in rabbit diets leads to an increase in the total white blood cells, total VFA and acetic acid concentration, and a decrease in the ammonia levels, as well as the digestibility when CR and high level of LS were supplemented, without causing any adverse effects on other parameters.
The effect of replacing soya bean oil with glycerol in diets on performance, egg quality and egg fatty acid composition in laying hens
- Y. Cufadar, R. Göçmen, G. Kanbur
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- 14 September 2015, pp. 19-24
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The objective of this experiment was to replace soya bean oil with glycerol in laying hen diets and assess the change’s effect on performance, parameters of egg quality and the egg fatty acid profile. A total of 60 44-week-old Hy-Line W36 laying hens were distributed according to a completely randomised experimental design into four treatments consisting of glycerol substitutions for soya bean oil dietary at varying inclusion levels (0%, 25%, 50% and 75%), with five replicates of three birds each. Dietary treatments had no significant effect on BW change, egg production, feed intake, feed conversion ratio, egg weight and egg mass of laying hens. The inclusion of glycerol in the diet of laying hens had no significant effect on egg specific gravity, eggshell breaking strength, eggshell weight, eggshell thickness, egg shape index, albumen index, yolk index, haugh unit, albumen pH, yolk pH and egg yolk colour values. The inclusion of glycerol in the diet of laying hens had no significant effect on palmitic, palmitoleic, stearic, oleic and linolenic acid contents of the egg yolk. The linoleic acid and polyunsaturated fatty acid contents of the egg yolk significantly decreased with the higher levels of dietary glycerol supplementation (P<0.05). The results of this study show that it is possible to replace 75% of soya bean oil (4.5% in diet) with glycerol.
Use of short-term breath measures to estimate daily methane production by cattle
- J. I. Velazco, D. G. Mayer, S. Zimmerman, R. S. Hegarty
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- 25 August 2015, pp. 25-33
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Methods to measure enteric methane (CH4) emissions from individual ruminants in their production environment are required to validate emission inventories and verify mitigation claims. Estimates of daily methane production (DMP) based on consolidated short-term emission measurements are developing, but method verification is required. Two cattle experiments were undertaken to test the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate did not differ from DMP measured in respiration chambers (RC). Short-term emission rates were obtained from a GreenFeed Emissions Monitoring (GEM) unit, which measured emission rate while cattle consumed a dispensed supplement. In experiment 1 (Expt. 1), four non-lactating cattle (LW=518 kg) were adapted for 18 days then measured for six consecutive periods. Each period consisted of 2 days of ad libitum intake and GEM emission measurement followed by 1 day in the RC. A prototype GEM unit releasing water as an attractant (GEM water) was also evaluated in Expt. 1. Experiment 2 (Expt. 2) was a larger study based on similar design with 10 cattle (LW=365 kg), adapted for 21 days and GEM measurement was extended to 3 days in each of the six periods. In Expt. 1, there was no difference in DMP estimated by the GEM unit relative to the RC (209.7 v. 215.1 g CH4/day) and no difference between these methods in methane yield (MY, 22.7 v. 23.7 g CH4/kg of dry matter intake, DMI). In Expt. 2, the correlation between GEM and RC measures of DMP and MY were assessed using 95% confidence intervals, with no difference in DMP or MY between methods and high correlations between GEM and RC measures for DMP (r=0.85; 215 v. 198 g CH4/day SEM=3.0) and for MY (r=0.60; 23.8 v. 22.1 g CH4/kg DMI SEM=0.42). When data from both experiments was combined neither DMP nor MY differed between GEM- and RC-based measures (P>0.05). GEM water-based estimates of DMP and MY were lower than RC and GEM (P<0.05). Cattle accessed the GEM water unit with similar frequency to the GEM unit (2.8 v. 3.5 times/day, respectively) but eructation frequency was reduced from 1.31 times/min (GEM) to once every 2.6 min (GEM water). These studies confirm the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate using GEM does not differ from measures of DMP obtained from RCs. Further, combining many short-term measures of methane production rate during supplement consumption provides an estimate of DMP, which can be usefully applied in estimating MY.
Effects of nitrogen fertilisation rate and maturity of grass silage on methane emission by lactating dairy cows
- D. Warner, B. Hatew, S. C. Podesta, G. Klop, S. van Gastelen, H. van Laar, J. Dijkstra, A. Bannink
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- 12 August 2015, pp. 34-43
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Grass silage is typically fed to dairy cows in temperate regions. However, in vivo information on methane (CH4) emission from grass silage of varying quality is limited. We evaluated the effect of two rates of nitrogen (N) fertilisation of grassland (low fertilisation (LF), 65 kg of N/ha; and high fertilisation (HF), 150 kg of N/ha) and of three stages of maturity of grass at cutting: early maturity (EM; 28 days of regrowth), mid maturity (MM; 41 days of regrowth) and late maturity (LM; 62 days of regrowth) on CH4 production by lactating dairy cows. In a randomised block design, 54 lactating Holstein–Friesian dairy cows (168±11 days in milk; mean±standard error of mean) received grass silage (mainly ryegrass) and compound feed at 80 : 20 on dry matter basis. Cows were adapted to the diet for 12 days and CH4 production was measured in climate respiration chambers for 5 days. Dry matter intake (DMI; 14.9±0.56 kg/day) decreased with increasing N fertilisation and grass maturity. Production of fat- and protein-corrected milk (FPCM; 24.0±1.57 kg/day) decreased with advancing grass maturity but was not affected by N fertilisation. Apparent total-tract feed digestibility decreased with advancing grass maturity but was unaffected by N fertilisation except for an increase and decrease in N and fat digestibility with increasing N fertilisation, respectively. Total CH4 production per cow (347±13.6 g/day) decreased with increasing N fertilisation by 4% and grass maturity by 6%. The smaller CH4 production with advancing grass maturity was offset by a smaller FPCM and lower feed digestibility. As a result, with advancing grass maturity CH4 emission intensity increased per units of FPCM (15.0±1.00 g CH4/kg) by 31% and digestible organic matter intake (33.1±0.78 g CH4/kg) by 15%. In addition, emission intensity increased per units of DMI (23.5±0.43 g CH4/kg) by 7% and gross energy intake (7.0±0.14% CH4) by 9%, implying an increased loss of dietary energy with advancing grass maturity. Rate of N fertilisation had no effect on CH4 emissions per units of FPCM, DMI and gross energy intake. These results suggest that despite a lower absolute daily CH4 production with a higher N fertilisation rate, CH4 emission intensity remains unchanged. A significant reduction of CH4 emission intensity can be achieved by feeding dairy cows silage of grass harvested at an earlier stage of maturity.
Effect of protein supplementation on ruminal parameters and microbial community fingerprint of Nellore steers fed tropical forages
- C. B. P. Bento, A. C. Azevedo, D. I. Gomes, E. D. Batista, L. M. A. Rufino, E. Detmann, H. C. Mantovani
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- 11 August 2015, pp. 44-54
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In tropical regions, protein supplementation is a common practice in dairy and beef farming. However, the effect of highly degradable protein in ruminal fermentation and microbial community composition has not yet been investigated in a systematic manner. In this work, we aimed to investigate the impact of casein supplementation on volatile fatty acids (VFA) production, specific activity of deamination (SAD), ammonia concentration and bacterial and archaeal community composition. The experimental design was a 4×4 Latin square balanced for residual effects, with four animals (average initial weight of 280±10 kg) and four experimental periods, each with duration of 29 days. The diet comprised Tifton 85 (Cynodon sp.) hay with an average CP content of 9.8%, on a dry matter basis. Animals received basal forage (control) or infusions of pure casein (230 g) administered direct into the rumen, abomasum or divided (50 : 50 ratio) in the rumen/abomasum. There was no differences (P>0.05) in ruminal pH and microbial protein concentration between supplemented v. non-supplemented animals. However, in steers receiving ruminal infusion of casein the SAD and ruminal ammonia concentration increased 33% and 76%, respectively, compared with the control. The total concentration of VFA increased (P<0.05) in steers receiving rumen infusion of casein. SAD and the microbial protein concentration did not vary significantly among treatments during the feeding cycle, but mean SAD values were greater in steers supplemented in the rumen and rumen/abomasum. Ruminal ammonia concentration was positively correlated with SAD in animals receiving ruminal infusion of casein. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed low similarity between treatments, animals and time of sample collection. Richness analysis and determination of the Shannon–Wiener index indicated no differences (P>0.05) in species richness and diversity of γ-proteobacteria, firmicutes and archaea between non-supplemented Nellore steers and steers receiving casein supplementation in the rumen. However, species richness and the Shannon–Wiener index were lower (P<0.05) for the phylum bacteroidetes in steers supplemented with casein in the rumen compared with non-supplemented animals. Venn diagrams indicated that the number of unique bands varied considerably among individual animals and was usually higher in number for non-supplemented steers compared with supplemented animals. These results add new knowledge about the effects of ruminal and postruminal protein supplementation on metabolic activities of rumen microbes and the composition of bacterial and archaeal communities in the rumen of steers.
Feeding dried distillers grains with solubles to lactating beef cows: impact of excess protein and fat on cow performance, milk production and pre-weaning progeny growth
- C. N. Shee, R. P. Lemenager, J. P. Schoonmaker
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- 24 August 2015, pp. 55-63
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Multiparous Angus×Simmental cows (n=54, 5.22±2.51 years) with male progeny were fed one of two diets supplemented with either dried distillers grains with solubles (DDGS) or soybean meal (CON), from calving until day 129 postpartum (PP) to determine effects of excess protein and fat on cow performance, milk composition and calf growth. Diets were formulated to be isocaloric and consisted of rye hay and DDGS (19.4% CP; 8.76% fat), or corn silage, rye hay and soybean meal (11.7% CP; 2.06% fat). Cow–calf pairs were allotted by cow and calf age, BW and breed. Cow BW and body condition score (BCS; P⩾0.13) were similar throughout the experiment. A weigh-suckle-weigh was performed on day 64 and day 110±10 PP to determine milk production. Milk was collected on day 68 and day 116±10 PP for analysis of milk components. Milk production was unaffected (P⩾0.75) by dietary treatments. Milk urea nitrogen was increased at both time points in DDGS compared with CON cows (P<0.01). Protein was decreased (P=0.01) and fat was increased (P=0.01) in milk from DDGS compared with CON cows on day 68 PP. Compared to CON, DDGS decreased medium chain FA (P<0.01) and increased long chain FA (P<0.01) at both time points. Saturated FA content of milk was decreased (P<0.01) at both time-points in DDGS compared with CON cows, which resulted in an increase (P<0.01) in monounsaturated and polyunsaturated FA, including cis-9, trans-11 conjugated linoleic acid. Daily gain of the DDGS calves was increased (P=0.01) compared with CON calves, resulting in heavier BW on day 129 (P=0.01). Heavier BW of DDGS calves was maintained through weaning (P=0.01). Timed-artificial insemination (TAI) rates were greater for cows fed DDGS compared with cows fed CON (P<0.02), but dietary treatment had no effect on overall pregnancy rates (P=0.64). In summary, feeding DDGS to lactating beef cows did not change cow BW or BCS, but did improve TAI rates and altered milk composition compared with CON. As a result, male progeny from cows fed DDGS during lactation had greater average daily gain and were heavier at day 129 and at weaning compared with male progeny from cows fed a control diet.
Effect of dietary cation–anion difference on ruminal metabolism, total apparent digestibility, blood and renal acid–base regulation in lactating dairy cows
- C. M. M. R. Martins, M. A. Arcari, K. C. Welter, J. L. Gonçalves, M. V. Santos
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- 20 August 2015, pp. 64-74
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The present study aimed to evaluate the effect of dietary cation–anion difference (DCAD) on ruminal fermentation, total apparent digestibility, blood and renal metabolism of lactating dairy cows. Sixteen Holstein cows were distributed in four contemporary 4×4 Latin Square designs, which consisted of four periods of 21 days and four treatments according to DCAD: +290; +192; +98 and −71 milliequivalent (mEq)/kg dry matter (DM). Ruminal pH and concentrations of acetic and butyric acid increased linearly according to the increase of DCAD. Similarly, NDF total apparent digestibility linearly increased by 6.38% when DCAD increased from −71 to 290 mEq/kg DM [Y=65.90 (SE=2.37)+0.0167 (SE=0.0068)×DCAD (mEq/kg DM)]. Blood pH was also increased according to DCAD, which resulted in reduction of serum concentrations of Na, K and ionic calcium (iCa). To maintain the blood acid–base homeostasis, renal metabolism played an important role in controlling serum concentrations of Na and K, since the Na and K urinary excretion increased linearly by 89.69% and 46.06%, respectively, from −71 to 290 mEq/kg DM. Changes in acid–base balance of biological fluids may directly affect the mineral composition of milk, as milk concentrations of Na, K, iCa and chlorides were reduced according to blood pH increased. Thus, it can be concluded that the increase of DCAD raises the pH of ruminal fluid, NDF total apparent digestibility, and blood pH, and decreases the milk concentration of cationic minerals, as well as the efficiency of Na utilization to milk production.
Physiology and functional biology of systems
Review Article
Invited review: mesenchymal progenitor cells in intramuscular connective tissue development
- Z. G. Miao, L. P. Zhang, X. Fu, Q. Y. Yang, M. J. Zhu, M. V. Dodson, M. Du
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- Published online by Cambridge University Press:
- 09 September 2015, pp. 75-81
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The abundance and cross-linking of intramuscular connective tissue contributes to the background toughness of meat, and is thus undesirable. Connective tissue is mainly synthesized by intramuscular fibroblasts. Myocytes, adipocytes and fibroblasts are derived from a common pool of progenitor cells during the early embryonic development. It appears that multipotent mesenchymal stem cells first diverge into either myogenic or non-myogenic lineages; non-myogenic mesenchymal progenitors then develop into the stromal-vascular fraction of skeletal muscle wherein adipocytes, fibroblasts and derived mesenchymal progenitors reside. Because non-myogenic mesenchymal progenitors mainly undergo adipogenic or fibrogenic differentiation during muscle development, strengthening progenitor proliferation enhances the potential for both intramuscular adipogenesis and fibrogenesis, leading to the elevation of both marbling and connective tissue content in the resulting meat product. Furthermore, given the bipotent developmental potential of progenitor cells, enhancing their conversion to adipogenesis reduces fibrogenesis, which likely results in the overall improvement of marbling (more intramuscular adipocytes) and tenderness (less connective tissue) of meat. Fibrogenesis is mainly regulated by the transforming growth factor (TGF) β signaling pathway and its regulatory cascade. In addition, extracellular matrix, a part of the intramuscular connective tissue, provides a niche environment for regulating myogenic differentiation of satellite cells and muscle growth. Despite rapid progress, many questions remain in the role of extracellular matrix on muscle development, and factors determining the early differentiation of myogenic, adipogenic and fibrogenic cells, which warrant further studies.
Research Article
Physiological and behavioral basis for the successful adaptation of goats to severe water restriction under hot environmental conditions
- M. Kaliber, N. Koluman, N. Silanikove
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- 10 August 2015, pp. 82-88
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Among domestic ruminants, goats are renowned for their ability to tolerate water deprivation, water restriction and energy restriction. However, some basic questions regarding their ability to endure water restriction under heat stress are still open. Three levels of water restriction (56%, 73% and 87% of the ad libitum) were imposed on 20 cross-bred 3-year-old female goats (75% German Fawn and 25% Hair Goat) distributed into four groups, with five animals per treatment. The experiment was conducted from the beginning of July to the end of August in a farm located in the Eastern Mediterranean region of Turkey (40 m in altitude; 36 59' N, 35 18'E), in which subtropical weather conditions prevail. The average daily temperature during the experiment was 34.2°C, whereas the highest and lowest temperatures were 42°C and 23.1°C, respectively. The average relative humidity was 68.2% and wind speed was 1.2 km/h. Weekly average thermal heat indexes during the experiment were 78.3 (week 1), 79.1 (week 2), 80.1 (weak 3), 79.8 (weak 4), 81.3 (weak 5) and on average 79.7. Feed intake, heart rate, thermoregulatory responses (rectal temperature, respiration rate), blood plasma concentrations of ions (Na, K), antidiuretic hormone (ADH), metabolites (glucose, cholesterol, creatinine and urea) and behavioral aspects (standing, walking, lying) were studied over 30 days. The responses to water restriction were proportional to the level of restriction. The reductions in feed intake (up to 13%), BW (up to 4.6%) and the increases in rectal temperature (0.5°C) and breath rate (10 respirations/min) were moderate and also were far from responses encountered under severe heat and water stresses. The increase in plasma Na (from 119 to 140 mM) and ADH concentrations (from 12.6 to 17.4 pg/ml) indicates that the physiological response to water restriction was in response to mild dehydration, which also explains the increase in blood plasma concentrations of glucose, cholesterol, creatinine and urea. Behavioral responses (reduction in walking from 226 to 209 min/day and increase in lying from 417 to 457 min/day) were associated with conservation of energy or thermoregulation (reducing the exposure to direct radiation).
Risk factors associated with lambing traits
- N. McHugh, D. P. Berry, T. Pabiou
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- 12 August 2015, pp. 89-95
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The objective of this study was to establish the risk factors associated with both lambing difficulty and lamb mortality in the Irish sheep multibreed population. A total of 135 470 lambing events from 42 675 ewes in 839 Irish crossbred and purebred flocks were available. Risk factors associated with producer-scored ewe lambing difficulty score (scale of one (no difficulty) to four (severe difficulty)) were determined using linear mixed models. Risk factors associated with the logit of the probability of lamb mortality at birth (i.e. binary trait) were determined using generalised estimating equations. For each dependent variable, a series of simple regression models were developed as well as a multiple regression model. In the simple regression models, greater lambing difficulty was associated with quadruplet bearing, younger ewes, of terminal breed origin, lambing in February; for example, first parity ewes experienced greater (P<0.001) lambing difficulty (1.56±0.02) than older ewes. The association between lambing difficulty and all factors persisted in the multiple regression model, and the trend in fixed effects level solutions did not differ from the trend observed in the simple regression models. In the simple regression analyses, a greater odds of lamb mortality was associated with male lambs (1.31 times more likely of death than females), lambs of very light (2 to 3 kg) and very heavy (>7.0 kg) birth weights, quadruplet born lambs and lambs that experienced a more difficult lambing (predicted probability of death for lambs that required severe and veterinary assistance of 0.15 and 0.32, respectively); lambs from dual-purpose breeds and born to younger ewes were also at greater risk of mortality. In the multiple regression model, the association between ewe parity, age at first lambing, year of lambing and lamb mortality no longer persisted. The trend in solutions of the levels of each fixed effect that remained associated with lamb mortality in the multiple regression model, did not differ from the trends observed in the simple regression models although the differential in relative risk between the different lambing difficulty scores was greater in the multiple regression model. Results from this study show that many common flock- and animal-level factors are associated with both lambing difficulty and lamb mortality and management of different risk category groups (e.g. scanned litter sizes, ewe age groups) can be used to appropriately manage the flock at lambing to reduce their incidence.
Associations between feed efficiency, sexual maturity and fertility-related measures in young beef bulls
- A. B. P. Fontoura, Y. R. Montanholi, M. Diel de Amorim, R. A. Foster, T. Chenier, S. P. Miller
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- 09 September 2015, pp. 96-105
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The beef industry has emphasized the improvement of feed utilization, as measured by modeling feed intake through performance traits to calculate residual feed intake (RFI). Evidence supports an inverse relationship between feed efficiency and reproductive function. The objective of this study was to determine the relationship of reproductive assessments and RFI unadjusted (RFIKoch) or adjusted for body composition (RFIus) and the relationship among fertility-related parameters. In total, 34 crossbred bulls were housed together for 112 days of performance evaluation, followed by assessment of scrotum IR imaging, scrotal circumference, testes ultrasonography and semen quality parameters at 377±33.4 days of age. Bulls were slaughtered at 389±34.0 days of age, and analyses of carcass composition, biometrics and histomorphometry of the testis and epididymis were conducted. Bulls were grouped into two subpopulations based on divergence of RFI, and within each RFI model either by including 50% of the population (Halves, high and low RFI, n=17) or 20.6% extremes of the population (Tails, high and low RFI, n=7). The means of productive performance and fertility-related measures were compared through these categories. Pearson’s correlation was calculated among fertility-related measures. In the Halves subpopulation of the RFIus, sperm of low-RFI bulls had decreased progressive motility (47.30% v. 59.90%) and higher abundance of tail abnormalities (4.30% v. 1.80%) than that of high-RFI bulls. In the Tails subpopulation of the RFIKoch, low RFI displayed less variation in the scrotum surface temperature (0.62°C v. 1.16°C), decreased testis echogenicity (175.50 v 198.00 pixels) and larger (60.90 v. 56.80 mm2) but less-developed seminiferous tubules than high-RFI bulls. The evaluation of fertility-related parameters indicated that a higher percentage of immature seminiferous tubules was correlated with occurrence of sperm with distal droplets (r=0.59), a larger temperature variation at the top of the scrotum was correlated with improved sperm progressive motility (r=0.38), a lower occurrence of sperm loose head abnormalities was correlated with larger temperature variation at the lower part of the scrotum (r=−0.43), and a lower minimum testis echogenicity (r=−0.59) and smaller scrotal circumference (r=0.72) were correlated with age. The adjustment for body composition (RFI determination) enabled distinct biological inferences about reproduction and feed efficiency when compared with the non-adjusted model. However, both RFI models and the correlation analysis supported the hypothesis that feed-efficient bulls have features of delayed sexual maturity. Overall, the assessment of fertility-related measurements is important to avoid the improvement of feed efficiency at the expense of reproductive function in young bulls.
Modelling impacts of performance on the probability of reproducing, and thereby on productive lifespan, allow prediction of lifetime efficiency in dairy cows
- H. N. Phuong, P. Blavy, O. Martin, P. Schmidely, N. C. Friggens
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- 24 August 2015, pp. 106-116
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Reproductive success is a key component of lifetime efficiency – which is the ratio of energy in milk (MJ) to energy intake (MJ) over the lifespan, of cows. At the animal level, breeding and feeding management can substantially impact milk yield, body condition and energy balance of cows, which are known as major contributors to reproductive failure in dairy cattle. This study extended an existing lifetime performance model to incorporate the impacts that performance changes due to changing breeding and feeding strategies have on the probability of reproducing and thereby on the productive lifespan, and thus allow the prediction of a cow’s lifetime efficiency. The model is dynamic and stochastic, with an individual cow being the unit modelled and one day being the unit of time. To evaluate the model, data from a French study including Holstein and Normande cows fed high-concentrate diets and data from a Scottish study including Holstein cows selected for high and average genetic merit for fat plus protein that were fed high- v. low-concentrate diets were used. Generally, the model consistently simulated productive and reproductive performance of various genotypes of cows across feeding systems. In the French data, the model adequately simulated the reproductive performance of Holsteins but significantly under-predicted that of Normande cows. In the Scottish data, conception to first service was comparably simulated, whereas interval traits were slightly under-predicted. Selection for greater milk production impaired the reproductive performance and lifespan but not lifetime efficiency. The definition of lifetime efficiency used in this model did not include associated costs or herd-level effects. Further works should include such economic indicators to allow more accurate simulation of lifetime profitability in different production scenarios.
Behaviour, welfare and health
Research Article
Simplifying the Welfare Quality® assessment protocol for broiler chicken welfare
- I. C. de Jong, V. A. Hindle, A. Butterworth, B. Engel, P. Ferrari, H. Gunnink, T. Perez Moya, F. A. M. Tuyttens, C. G. van Reenen
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- Published online by Cambridge University Press:
- 26 August 2015, pp. 117-127
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Welfare Quality® (WQ) assessment protocols place the emphasis on animal-based measures as an indicator for animal welfare. Stakeholders, however, emphasize that a reduction in the time taken to complete the protocol is essential to improve practical applicability. We studied the potential for reduction in time to complete the WQ broiler assessment protocol and present some modifications to the protocol correcting a few errors in the original calculations. Data was used from 180 flocks assessed on-farm and 150 flocks assessed at the slaughter plant. Correlations between variables were calculated, and where correlation was moderate, meaningful and promising (in terms of time reduction), simplification was considered using one variable predicted from another variable. Correlation analysis revealed a promising correlation between severe hock burn and gait scores on-farm. Therefore, prediction of gait scores using hock burn scores was studied further as a possible simplification strategy (strategy 1). Measurements of footpad dermatitis, hock burn, cleanliness and gait score on-farm correlated moderately to highly with slaughter plant measurements of footpad dermatitis and/or hock burn, supporting substitution of on-farm measurements with slaughter plant data. A simplification analysis was performed using footpad dermatitis, hock burn, cleanliness and gait scores measured on-farm predicted from slaughter plant measurements of footpad dermatitis and hock burn (strategy 2). Simplification strategies were compared with the full assessment protocol. Close agreement was found between the full protocol and both simplification strategies although large confidence intervals were found for specificity of the simplified models. It is concluded that the proposed simplification strategies are encouraging; strategy 1 can reduce the time to complete the on-farm assessment by ~1 h (25% to 33% reduction) and strategy 2 can reduce on-farm assessment time by ~2 h (50% to 67% reduction). Both simplification strategies should, however, be validated further, and tested on farms with a wide distribution across the different welfare categories of WQ.
Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets
- H. M.-L. Andersen, L. J. Pedersen
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- Published online by Cambridge University Press:
- 11 September 2015, pp. 128-134
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It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1st week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first suckling were registered by direct observation. The piglet’s rectal temperature (RT) was measured 15, 30, 60, 120, 180, 240 min after birth and 12, 14 and 24 h after birth of first piglet. Piglets were weighed at birth, 24 and 48 h and 7 days after birth. Data were analysed in a mixed model in SAS. The drop in RT was lower in HG compared with CG (P=0.002), and the RT in HG remained higher than in CG from 30 to 240 min after birth (P<0.05), whereas no difference was found at 12 h after birth of first piglet (P=0.92). Piglets in HG stayed longer in zone 1 than those in CG (P=0.01), whereas time to reach udder (P=0.35) and to first suckling (P=0.56) did not differ. No difference in weight gain was found between piglets in HG and CG at 24 h (P=0.23), 48 h (P=0.28) and 7 days after birth (P=0.44). Birth weight had a positive effect on RT (P<0.001) and reduced time to leave zone 1 (P<0.01), reach udder (P<0.001) and time to first suckling (P<0.001). The results showed that radiant heating behind the sows reduced hypothermia in new-born piglets and indicate that providing heat during the first half hour after birth is important.
Promoting positive states: the effect of early human handling on play and exploratory behaviour in pigs
- M. Zupan, T. Rehn, D. de Oliveira, L. J. Keeling
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- Published online by Cambridge University Press:
- 20 August 2015, pp. 135-141
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It is known that tactile stimulation (TS) during ontogeny modifies brain plasticity and enhances the motor and cognitive skills. Our hypothesis was that early handling including TS would increase play and exploratory behaviour in commercial pigs under standardized test conditions. Piglets from 13 litters were subjected to three handling treatments from 5 to 35 days of age: all the piglets were handled (H), none of the piglets were handled (NH) or half of the piglets in the litter were handled (50/50). At 42 days of age, the pigs’ behaviour was observed in pairs in a novel pen with a ‘toy’ (tug rope). The main results were that more locomotor play was performed by pigs from litters where all or half of them had been handled, whereas social exploratory behaviour was more pronounced in pigs from litters where half of them had been handled. Although behaviour was affected by the interaction of treatment with sex or with weight category, we propose that the handling procedure does seem to have acted to increase locomotor skills and that handling half of the piglets in the litter may have triggered a series of socio-emotional interactions that were beneficial for the whole group.
Does group size have an impact on welfare indicators in fattening pigs?
- S. E. K. Meyer-Hamme, C. Lambertz, M. Gauly
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- Published online by Cambridge University Press:
- 25 August 2015, pp. 142-149
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Production systems for fattening pigs have been characterized over the last 2 decades by rising farm sizes coupled with increasing group sizes. These developments resulted in a serious public discussion regarding animal welfare and health in these intensive production systems. Even though large farm and group sizes came under severe criticism, it is still unknown whether these factors indeed negatively affect animal welfare. Therefore, the aim of this study was to assess the effect of group size (<15 v. 15 to 30 v. >30 pigs/pen) on various animal-based measures of the Welfare Quality® protocol for growing pigs under conventional fattening conditions. A total of 60 conventional pig fattening farms with different group sizes in Germany were included. Moderate bursitis (35%) was found as the most prevalent indicator of welfare-related problems, while its prevalence increased with age during the fattening period. However, differences between group sizes were not detected (P>0.05). The prevalence of moderately soiled bodies increased from 9.7% at the start to 14.2% at the end of the fattening period, whereas large pens showed a higher prevalence (15.8%) than small pens (10.4%; P<0.05). With increasing group size, the incidence of moderate wounds with 8.5% and 11.3% in small- and medium-sized pens, respectively, was lower (P<0.05) than in large-sized ones (16.3%). Contrary to bursitis and dirtiness, its prevalence decreased during the fattening period. Moderate manure was less often found in pigs fed by a dry feeder than in those fed by a liquid feeding system (P<0.05). The human–animal relationship was improved in large in comparison to small groups. On the contrary, negative social behaviour was found more often in large groups. Exploration of enrichment material decreased with increasing live weight. Given that all animals were tail-docked, tail biting was observed at a very low rate of 1.9%. In conclusion, the results indicate that BW and feeding system are determining factors for the welfare status, while group size was not proved to affect the welfare level under the studied conditions of pig fattening.
Effect of a topical anaesthetic formulation on the cortisol response to surgical castration of unweaned beef calves
- D. McCarthy, S. Lomax, P. A. Windsor, P. J. White
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- Published online by Cambridge University Press:
- 28 July 2015, pp. 150-156
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Impracticality and cost of existing pain management strategies during surgical castration of beef cattle have limited their widespread implementation on-farm. A farmer-applied topical anaesthetic formulation, originally developed and used commercially to mitigate the pain of mulesing in lambs, was investigated for its potential use for managing pain in surgically castrated calves. This formulation contained lidocaine, bupivacaine, adrenalin and cetrimide. In this study, 24 Angus bull calves were randomly allocated to (1) surgical castration (C, n=8), (2) surgical castration with the post-operative application of topical anaesthetic (CTA, n=8) and (3) sham castration/control (CON, n=8). The experiment was conducted over 2 days, with treatment groups evenly represented across each day. Calves were habituated to handling before the experiment and blood samples were collected for plasma cortisol measurement at defined time periods before, at and post treatment, (at −0.5, 0 h, then +0.5, 1, 1.5, 2, 4 and 6 h). There was a significant effect of time on cortisol concentrations across all treatment groups (P<0.01), with lowest concentrations at −0.5 and 6 h and peak concentration at 0.5 h being significantly higher than the cortisol response at 0 h. The effect of treatment was not significant (P=0.077), however, there was a trend for CON calves to display lower cortisol concentrations than C and CTA calves and CTA calves to display lower cortisol concentrations than C calves. The mean area under the curve (AUC) of CON calves was significantly lower than those of C and CTA calves (P=0.04), however, there was no significant difference between the AUCs of CTA and C calves. Immediate application of topical anaesthetic after surgical castration did not significantly reduce plasma cortisol concentrations. However, the trend for CTA calves to display lower cortisol concentrations than C calves warrants further investigation into the use of TA for pain relief of surgically castrated beef calves.
Product quality, human health and well-being
Research Article
Influence of gestational maternal feed restriction on growth performance and meat quality of rabbit offsprings
- M. Goliomytis, E.-P. Skoupa, A. Konga, G. K. Symeon, M. A. Charismiadou, S. G. Deligeorgis
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- Published online by Cambridge University Press:
- 09 September 2015, pp. 157-162
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The purpose of the present study was to evaluate the effect of feed restriction during pregnancy on reproductive performance of rabbit does and growth performance and meat quality of their offspring. A total of 26 primiparous non lactating does were equally divided into two treatment groups: the control group (C, n=13) that was fed ad libitum throughout gestation and the feed restricted group (R, n=13) that was fed to 75% of maintenance energy requirements from the 7th to the 26th day of gestation. Rabbit offsprings were weaned at 35 days of age and grown until the 72 days of age when they were slaughtered for meat quality assessment. Meat quality traits measured were pH24, colour (L*, a*, b*), percentage of released water, cook loss, shear values and intramuscular fat. At kindling, R does produced smaller litter weights compared with those of does from group C, 447.8 and 591.4 g, respectively, and smaller individual kit birth weights, 56.2 and 71.5 g, respectively (P<0.05). Ratio of stillborn kits and mortality rate from parturition until weaning was higher (P<0.05) in the R group, 21.4% and 11.1%, respectively, in comparison with the C group, 8.1% and 3.5%, respectively. Litter size and gestation length were unaffected by maternal undernutrition. Kit birth weight treatment differences were eliminated at weaning because of compensatory growth (P>0.05). Performance and meat quality characteristics of fattening rabbits at 72 days of age were not influenced by gestational feed restriction of their mothers (P>0.05). Taking into consideration that, simultaneous gestation and lactation in rabbit does may be simulated by gestational feed restriction, results of the present study suggest that lactating does can support a simultaneous gestation without any adverse effect on the offsprings’ quantitative and qualitative performance at the expense of increased mortality rates at parturition and until weaning.
Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress
- C. P. Zeferino, C. M. Komiyama, V. C. Pelícia, V. B. Fascina, M. M. Aoyagi, L. L. Coutinho, J. R. Sartori, A. S. A. M. T. Moura
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- Published online by Cambridge University Press:
- 16 September 2015, pp. 163-171
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The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2×3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature×diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.