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One hundred and sixty pigs were used to evaluate dietary copper (Cu) and zinc (Zn) supplementation on performance, fecal mineral levels, body mineral status and carcass and meat quality. Diets differed in mineral form (MF) (Cu and Zn in the form of proteinate amino acid chelate (organic) or sulfate (inorganic)) and inclusion level (IL) (27 mg/kg of total Cu and 65 mg/kg of total Zn (‘low’) or 156 mg/kg of total Cu and 170 mg/kg of total Zn (‘high’)) according to a 2 × 2 factorial arrangement of treatments. Pigs were used from 25 to 107 kg body weight (BW) and fed their respective diets ad libitum. Blood and fecal samples were collected on days 14 and 77 of the experiment. Blood was analyzed for concentration of Cu and Zn, hemoglobin (Hb), Cu content of red blood cells (RBC Cu) and alkaline phosphatase (ALP) and feces for Cu and Zn concentration. Hot carcass weight (HCW) and backfat depth were measured at slaughter and indices of meat quality were assessed on a section of longissimus thoracis. Liver, kidney and bone samples were collected immediately after slaughter and liver and kidney were tested for Cu and Zn content, while bone was only tested for Zn. Over the entire experimental period (25 to 107 kg BW) no significant treatment differences in average daily gain (ADG) or average daily feed intake (ADFI) occurred; however, feed conversion ratio (FCR) was improved by the inclusion of proteinate amino acid chelate (P = 0.012). Copper and Zn concentrations in feces were in direct proportion to the IL in the diet. Blood mineral levels were within normal physiological ranges in all treatments and tissue Cu and Zn concentrations increased with dietary IL (P < 0.05). Results indicate that Cu and Zn fecal concentrations were reduced by approximately 6-fold for Cu and by 2.5-fold for Zn by feeding 27 mg/kg Cu and 65 mg/kg Zn, in either the proteinate amino acid chelate or the sulfate form, compared with a diet containing 156 mg/kg Cu and 170 mg/kg Zn. This decrease in total dietary Cu and Zn did not reduce performance or mineral status of pigs.
Even though extensive research has examined the role of nutrition on milk fat composition, there is less information on the impact of forages on milk fatty acid (FA) composition. In the current study, the effect of replacing grass silage (GS) with maize silage (MS) as part of a total mixed ration on animal performance and milk FA composition was examined using eight multiparous mid-lactation cows in a replicated 4 × 4 Latin square with 28-day experimental periods. Four treatments comprised the stepwise replacement of GS with MS (0, 160, 334 and 500 g/kg dry matter (DM)) in diets containing a 54 : 46 forage : concentrate ratio on a DM basis. Replacing GS with MS increased (P < 0.001) the DM intake, milk yield and milk protein content. Incremental replacement of GS with MS in the diet enhanced linearly (P < 0.001) the proportions of 6:0–14:0, decreased (P < 0.01) the 16:0 concentrations, but had no effect on the total milk fat saturated fatty acid content. Inclusion of MS altered the distribution of trans-18:1 isomers and enhanced (P < 0.05) total trans monounsaturated fatty acid and total conjugated linoleic acid content. Milk total n-3 polyunsaturated fatty acid (PUFA) content decreased with higher amounts of MS in the diet and n-6 PUFA concentration increased, leading to an elevated n-6 : n-3 PUFA ratio. Despite some beneficial changes associated with the replacement of GS with MS, the overall effects on milk FA composition would not be expected to substantially improve long-term human health. However, the role of forages on milk fat composition must also be balanced against the increases in total milk and protein yield on diets containing higher proportions of MS.
The aims of the study were to measure the mRNA expression of brain-derived neurotrophic factor (BDNF) in bovine oocytes and early embryos derived from in vitro fertilization (IVF), parthenogenetic activation (PA) and nuclear transfer (NT), and to investigate the effects of BDNF on the development of IVF and parthenogenetic embryos. Bovine oocytes matured in vitro for 22 h were in vitro fertilized or parthenogenetic activated. By reverse transcription-PCR and quantitative real-time PCR, we found that germinal vesicle (GV) oocytes, metaphase II (MII) oocytes, 4-cell and 8-cell embryos, morulae, and blastocysts were all shown to express mRNA for BDNF. The mRNA levels for BDNF gene were different in bovine oocytes and IVF embryos at different stages (P < 0.01), with the highest expression in MII oocytes and the lowest expression in 8-cell embryos. The mRNA for BDNF was highly expressed in the PA and IVF blastocysts compared to the NT blastocysts (P < 0.01). Supplementation of culture media with BDNF at the concentration of 40 μg/l caused a significant increase in the rates of in vitro-fertilized blastocyst formation (P < 0.05) and parthenogenetic blastocyst formation (P < 0.05). However, the rate of oocyte cleavage in BDNF groups was not significantly different from that in the BDNF-free control (P > 0.05) after IVF or PA. We have also investigated the effects of BDNF on the growth of granulosa cells, which were used for co-culture of bovine early embryos. The results revealed that supplementation of culture media with 20 μg/l BDNF promoted the growth of granulosa cells (P < 0.01). Taken together, these results provided evidence for the role of neurotrophins in promoting early embryonic development as well as in the growth of granulosa cells by the co-culture system, indicating that BDNF can directly or indirectly promote bovine early embryo development.
Information on 26 434 German Warmblood horses born between 1992 and 2001 was used for multivariate genetic analyses of radiographic health, conformation and performance traits to compare different modes of single- and multiple-trait selection of sires. Results of standardized radiological examinations of 5155 Hanoverian Warmblood horses, conformation evaluations from studbook inspections of 20 603 mares, and performance evaluations from mare performance tests and auction horse inspections of 16 098 horses were used for multivariate genetic analyses. Genetic parameters were estimated with restricted maximum likelihood (REML), and relative breeding values (RBV) were predicted with best linear unbiased prediction (BLUP) in multivariate linear animal models for four radiographic health traits, three conformation traits and five performance traits. Heritability estimates for osseous fragments in fetlock joints (OFF), osseous fragments in hock joints (OFH), deforming arthropathy in hock joints (DAH) and distinct radiographic findings in the navicular bones (DNB) ranged between 0.15 and 0.35 after transformation to the liability scale. Front limb conformation, hind limb conformation, withers height, walk, trot, canter, rideability and free jumping showed heritabilities between 0.09 and 0.49 and additive genetic correlations with OFF, OFH, DAH and DNB ranging between −0.53 and +0.52. Selection of sires was based on RBV or combinations of RBV, with selection for individual traits or traits from one of the three considered trait groups being considered as single-trait selection, and selection for traits from more than one trait group being considered as multiple-trait selection. The selection modes were compared by means of the expected selection response after one generation, calculated as the relative change in the prevalences of the radiographic findings or the mean conformation or performance scores in the offspring of the selected sires when compared with the offspring of all sires. The prevalences of OFF, OFH, DAH and DNB decreased by 30% to 57% after single-trait selection and 14% to 29% after multiple-trait selection, while mean conformation and performance scores increased by up to 4%. The results indicated that it is possible to simultaneously improve the radiographic health of the limbs, limb conformation, quality of gaits and rideability. However, genetic progress in free jumping ability and style could only be achieved by single- or multiple-trait selection with focus on jumping performance.
The aim of this study was to compare rumen pH and time-budget in eight mid-lactation goats receiving two diets in a cross-over design (low-concentrate diet (L): 30% and high-concentrate diet (H): 60% concentrate). Feeding H increased daily intake (4.3 ± 0.08% v. 4.7 ± 0.08% of body weight for L and H, respectively) and daily milk production (3.01 ± 0.130 v. 3.50 ± 0.130 kg/day of 3.5% fat-corrected milk for L and H, respectively). It decreased milk fat and inverted the fat-to-protein ratio (1.07 ± 0.054 v. 0.94 ± 0.054 for L and H, respectively). As suggested by the percentage of time spent with rumen pH below 6.0 (23.4 ± 6.60% v. 39.9 ± 5.88% for L and H, respectively), H was more acidogenic than L. When offered H instead of L, goats spent less time eating (298 ± 17.5 v. 265 ± 17.5 min for L and H, respectively) and ruminating (521 ± 21.0 v. 421 ± 21.0 min for L and H, respectively) but more time resting (352 ± 27.1 v. 459 ± 21.1 min for L and H, respectively) over a 24-h period. They also tended to spend more time drinking (20 ± 2.9 v. 25 ± 2.9 min for L and H, respectively; P = 0.08) when offered H rather than L. These differences in activities were mainly observed during the first hours following feeding. When offered H, goats adapted their feeding behaviour around the feedings, which allowed them to limit the physiological disturbances potentially inducible by H and to increase milk production, without experiencing too much acidosis.
Whether the rumen microbes are able to synthesize and/or degrade long-chain alkanes in anaerobic conditions remains a question to be answered before these hydrocarbons can be confidently used as duodenal flow or rumen transit markers. In this context, an experiment in vitro was carried out to establish whether within a rumen liquor fermentation system, n-alkanes can be derived from de-waxed structures of the plant or from non-alkane wax components (long-chain fatty alcohols, long-chain fatty acids and esters), or may be metabolized by bacteria to other components or to shorter-chain hydrocarbons. Ryegrass was labelled with 14C in growth chambers under controlled conditions in order to use it as a substrate. The labelled material obtained was separated in three fractions: labelled alkanes, labelled de-waxed plant and labelled wax components without the alkanes. These fractions were used for three different incubations in vitro, which objectives were as follows: 1. To check whether rumen bacteria can synthesize alkanes from carbon structures other than waxes (e.g. sugars). 2. To verify whether rumen bacteria can metabolize the n-alkanes to other compounds. 3. To check whether rumen bacteria can synthesize n-alkanes from other carbon compounds from waxes. The results showed that there was neither bacterial synthesis nor metabolism of the n-alkanes in in vitro conditions.
Increasing rates of obesity and heart disease are compromising quality of life for a growing number of people. There is much research linking adult disease with the growth and development both in utero and during the first year of life. The pig is an ideal model for studying the origins of developmental programming. The objective of this paper was to construct percentile growth curves for the pig for use in biomedical studies. The body weight (BW) of pigs was recorded from birth to 150 days of age and their crown-to-rump length was measured over the neonatal period to enable the ponderal index (PI; kg/m3) to be calculated. Data were normalised and percentile curves were constructed using Cole’s lambda-mu-sigma (LMS) method for BW and PI. The construction of these percentile charts for use in biomedical research will allow a more detailed and precise tracking of growth and development of individual pigs under experimental conditions.
Within breeds and other captive populations, the risk of high inbreeding rates and loss of diversity can be high within (small) herds or subpopulations. When exchange of animals between different subpopulations is organised according to a rotational mating scheme, inbreeding rates can be restricted. Two such schemes, a breeding circle and a maximum avoidance of inbreeding scheme, are compared. In a breeding circle, flocks are organised in a circle where each flock serves as a donor flock for another flock, and the same donor–recipient combination is used in each breeding season. In the maximum inbreeding avoidance scheme, donor–recipient combinations change each year so that the use of the same combination is postponed as long as possible. Data from the Kempisch Heideschaap were used with computer simulations to determine the long-term effects of different breeding schemes. Without exchanging rams between flocks, high inbreeding rates (>1.5% per year) occurred. Both rotational mating schemes reduced inbreeding rates to on average 0.16% per year and variation across flocks in inbreeding rates, caused by differences in flock size, almost disappeared. Inbreeding rates with maximum inbreeding avoidance were more variable than with a breeding circle. Moreover, a breeding circle is easier to implement and operate. Breeding circles are thus efficient and flexible and can also be efficient for other captive populations, such as zoo populations of endangered wild species.
Dietary fat influences the physico-chemical properties of meat, and fatty acid (FA) composition may have implications on human health. The objectives of the experiment were to study tissue FA partitioning and the effect of dietary fat source on tissue FA composition. Seventy crossbred gilts (61.8 ± 5.2 kg BW average) were fed one of seven treatments: a diet containing a very low level of fat (no fat (NF)) and six fat-supplemented diets (10%: tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), fat blend (FB: 55% tallow, 35% SFO, 10% LO) and fish oil blend (FO: 40% fish oil, 60% LO). Differential tissue FA depositions were observed, with flare fat being the most saturated, followed by intermuscular, and subcutaneous being the least saturated. Monounsaturated fatty acid (MUFA) deposition showed an opposite tissue pattern. Subcutaneous fat showed the highest MUFAs, intermuscular fat showed intermediate values and flare fat showed the lowest MUFAs. Intramuscular polyunsaturated fatty acid (PUFA) content was less susceptible to dietary treatment modifications compared with other depots. Significant tissue FA modifications were observed due to dietary treatments, mainly in diets rich in PUFA. The saturated fatty acids (SFA) were high in NF-fed and low in HOSF-fed animals, MUFA were high in HOSF-fed and low in SFO-, LO- and FO-fed animals, while PUFA were high in SFO- and LO-fed and low in HOSF-, T- and NF-fed animals. Pigs fed LO and FB showed detectable levels of EPA, which depended on the linolenic content of the diet. The only effective way to increase tissue DHA contents was to add DHA in the diet through FO feeding. Araquidonic acid was high in SFO diets and low in LO and FB diets, and also high in intramuscular fat compared with other tissues. EPA and DHA were also high in intramuscular fat compared with other fat depots. The deposition of oleic and linoleic acids depended on the composition of dietary fat, as their deposition varied between diets, even at similar levels of intake of each FA. The NF diet resulted in the greatest proportion of SFAs (palmitic and stearic) of all treatments tested. SFAs were less susceptible to modification than MUFA in response to the different PUFA levels supplemented in the diet. T resulted in less fat deposition in some of the fat depots and more in others, suggesting that T could partition fat differently among fat depots.
We studied a group housing system as an alternative to the traditional pair housing of juvenile mink. The focus was on both the welfare and production of mink. The pairs were housed in standard mink cages, whereas the groups were in row cage systems consisting of three standard mink cages connected to each other. The welfare of the mink was evaluated by behavioural observations (stereotypies and social contacts), evaluation of the incidence of scars assumed to be caused by biting, and adrenal function (serum cortisol level after adrenocorticotropic hormone (ACTH) administration and adrenal mass). Feed consumption, pelt length, quality and price were used for comparing the two housing systems from the economic point of view. Although the incidence of scars showed that there might have been more aggressive behaviour among the group-housed than among the pair-housed mink, this was not observed unambiguously in behavioural observations, and, at least, aggression did not cause mortality or serious injuries to the animals as has been observed in some earlier studies. In addition, the housing system did not affect pelt size, and, although the quality of the pelts was slightly lower in the group than in pair-housed mink, there was only a tendency for lower pelt prices. The lower pelt prices in the group-housed mink might even be partially compensated for by the group-housed mink eating 10% to 20% less in the late autumn, due to thermoregulatory benefits, than their pair-housed conspecifics. The results on the frequency of stereotypic behaviour (but not adrenal function) suggest that the group-housed animals were possibly less stressed than the pair-housed animals. Group housing of juvenile farmed mink in a row cage system cannot be recommended before the effects on welfare and production are clarified in further studies.
Within-litter variation of piglet birth weight (BW0) is associated with an increased piglet mortality and a high variability in pig weight at weaning and weight or age at slaughter. Data collected in two experimental herds were used to quantify within-litter variability in BW0 and to assess the influence of factors mainly related to the sow. Within 24 h after birth, piglets born alive were individually weighed and stillborn piglets were collectively (first data set) or individually (second data set) weighed. The first data set was restricted to litters with no or only one stillborn piglet (3338 litters). It was used to assess the influence of genetic selection on BW0 variation by comparing litter characteristics before (1994 to 1996) and after (2001 to 2004) the development of hyperprolific sows in this herd. The second data set included all litters (n = 1596) from sows born between 2000 and 2004. For each litter, mean BW0 (mBW0) and its coefficient of variation (CVBW0) were calculated. Then, variance analyses were performed to test the influence of litter size, parity, year of sow birth and season at conception. Prolificacy improvement was associated with an increased CVBW0 in litters from pure Large White (LW) and Landrace × Large White (LR × LW) crossbred sows. The CVBW0 averaged 21% and was significantly influenced by litter size and parity. It increased from 15% to 24% when litter size varied from less than 10 piglets to more than 15 piglets. The proportion of small piglets (i.e. weighing less than 1 kg) increased concomitantly. The CVBW0 was not repeatable from a parity to the following. It was lowest for first and second parities (20%) and thereafter increased progressively. The CVBW0 was positively related to sow’s backfat thickness gain during gestation. Taking into account litter size, parity, year of sow birth and season at conception explained 20% of BW0 variation. Thus, major part of heterogeneity is due to other factors, presumably including embryo genotype, on the one hand, and factors that influence embryo and foetus development, such as epigenetic factors, on the other hand.
In this experiment, we assessed the effect of amino acid (AA) intake restriction in entire male Yorkshire pigs between 15 and 38 kg BW (restriction phase) on BW gain, body composition and plasma levels of blood urea nitrogen (BUN), cortisol, insulin-like growth factor I (IGF-I), growth hormone (GH) and leptin during the subsequent re-alimentation phase. During the restriction phase, 36 pigs were allotted to one of two dietary treatments: adequate AA intake (control) or AA-limiting diets (AA-30%). Thereafter, pigs were fed common non-limiting diets up to 110 kg BW. Throughout the experiment, pigs were scale-fed at 90% of the estimated voluntary daily digestible energy intake. At the end of the restriction phase, pigs on AA-30% had lesser BW gain (650 v. 784 g/day; P < 0.001), loin area (LA; 12.2 v. 14.2 cm2; P < 0.001), BUN (4.6 v. 6.3 mg/dl; P < 0.02), lesser plasma levels of IGF-I (440 v. 640 ng/m; P < 0.001) and cortisol (8.2 v. 19.2 μg/dl; P < 0.001), greater backfat thickness (BF; 7.56 v. 6.56 mm; P < 0.02), and greater plasma levels of leptin (2.7 v. 1.8 ng/ml; P = 0.027) and GH (3.3 v. 2.0 ng/ml; P = 0.05) than pigs on control. During the re-alimentation phase, previously restricted pigs showed full compensatory growth (CG) in terms of BW gain (1170 v. 1077 g/day; P < 0.002), whole-body protein deposition (Pd) (179 v. 163 g/day; P < 0.001) as well as physical and chemical body composition (whole-body lipid to body protein mass ratio, LB/PB; 1.14 v. 1.15; P > 0.10). Besides GH at 45 kg BW (4.2 v. 2.4 ng/ml; P = 0.066), there were no effects of previous AA intake restriction on leptin, IGF-I and BUN during the re-alimentation phase (P > 0.10). Plasma cortisol and IGF-I levels may act as an indicator of AA-induced restriction in Pd in growing pigs. Plasma BUN level does not appear as a sensitive indicator for compensatory Pd. Plasma leptin and GH levels allow for the involvement of the brain in controlling chemical body composition. Full CG was observed during the energy-dependent phase of Pd in growing pigs and might be driven by a target LB/PB, possibly mediated via plasma leptin, IGF-I and GH levels.
Texel muscling quantitative trait locus (TM-QTL) is a QTL on chromosome 18, originally identified in purebred UK Texel sheep, which was reported to increase ultrasonically measured muscle depth at the third lumbar vertebra by around 4% to 7%. The objective of the present study was to comprehensively evaluate the TM-QTL and to determine whether it could provide benefits to the UK sheep industry through increased carcass meat yield in crossbred slaughter lambs. Effects of this QTL on a range of carcass traits, including those measured in vivo and by dissection, were evaluated in heterozygous carrier and non-carrier lambs produced by crossing heterozygous carrier Texel rams with non-carrier Mule (Bluefaced Leicester × Scottish Blackface) ewes from a lowland flock. The TM-QTL was found to increase loin muscling in crossbred lambs at a given live weight or carcass weight, as measured by ultrasound, X-ray computed tomography (CT) and carcass dissection. Depth of M. longissimus lumborum (MLL) was greater in TM-QTL carrier lambs compared to non-carriers as measured by both ultrasound at the third lumbar vertebra (+4.5%; P = 0.033) and CT scanning at the fifth lumbar vertebra (+6.7%; P = 0.004). Width and area of MLL measured using CT were also greater in TM-QTL carrier lambs compared to non-carriers (+3.0%; P = 0.013 and +5.1%; P = 0.047, respectively). Loin muscle volume measured using CT was greater in TM-QTL carriers than in non-carriers (+5.9%; P = 0.005) and the dissected weight of the MLL was +7.1% greater in TM-QTL carriers compared to non-carriers (P < 0.001). The proportion of the total carcass lean meat yield (LMY) that was contained within the loin region was slightly higher in TM-QTL carriers than in non-carriers (0.154 v. 0.145; P = 0.006). However, TM-QTL was found to have no significant effect on the total weight or proportion of LMY or of saleable meat yield in the carcass measured by dissection, or on muscling in the hind leg measured by CT or dissection. This work has verified that the inheritance of TM-QTL is associated with increased loin muscling in crossbred lambs, as has previously been reported for purebred Texel lambs.
We investigated whether undernutrition during the second half of pregnancy impaired the behaviour of does and their kids at parturition and early mutual recognition. Twenty-two control and 22 underfed mixed-breed, multiparous dairy goats were used, together with their respective kids (control, n = 31: nine singles, 16 twins and six triplets; underfed, n = 32: 11 singles, 18 twins and three triplets). Undernutrition involved limiting protein and energy intake at 70% of the nutritional requirements for maintenance and foetal growth from day 70 of pregnancy until birth. The behaviour of mothers and their two first-born kids was observed for 90 min from the birth of each kid. Maternal olfactory recognition of the kid was assessed at 4 h post partum by testing selective nursing behaviour. Non-olfactory recognition was assessed at 8 h in a two-choice test excluding olfactory cues. In kids, preference for the mother was assessed in a two-choice test at either 12 or 24 h post partum. Bodyweight of does and kids were lower in the underfed group up to 2 weeks post partum. At parturition, licking, maternal bleating frequency and latency to nursing did not differ between nutritional groups. Control kids were faster than underfed kids to stand, search for and reach the udder, but underfed kids bleated more and tended to spend more time at the udder. Both control and underfed does accepted their own kid and rejected the alien in the selectivity test at 4 h. In contrast, at 8 h post partum, only control goats showed a significant preference for their own kid in the non-olfactory recognition test. Both control and underfed kids showed a preference for their own mother at 12 and 24 h and undernutrition during pregnancy had little influence on the performance of kids. However, 12 h-old underfed kids tended to be less active than control kids and visited their own mothers less than control kids. There were no significant correlations between the behaviour of the mother or of the kid at parturition and their performance in the discrimination tests. Overall, undernutrition in the second half of pregnancy appears to be more detrimental for the behaviour of the mother than for the kid. Furthermore, it has more impact on the establishment of maternal non-olfactory recognition than on maternal care at parturition or the establishment of maternal selectivity.
Cholecystokinin (CCK) can exert multiple actions on intestinal motility but its effect on the small-intestinal ‘minute rhythm’ (MR) is virtually unknown. Therefore, the electrical activity from the abomasal antrum, duodenal bulb, duodenum, jejunum and ileum was continuously recorded in six sheep before, during and after slow intravenous administration, of three doses each, of cholecystokinin-octapeptide (CCK-OP) and cerulein. In four of these sheep, two additional electrodes and the strain gauge force transducer were also inserted in the duodenum. Chronic experiments were performed in the fasted and non-fasted animals and saline or CCK peptides were injected during phases 1, 2a or 2b of the duodenal migrating myoelectric complex (MMC). The administration of both CCK peptides in various doses evoked an inhibitory effect mostly in the duodenal bulb, except for the lowest dose of cerulein. The effects of 20 times greater doses of CCK-OP than that of cerulein were more pronounced. The introduction of both CCK peptides during phase 1 of the MMC produced no marked or significant response. In non-fasted animals, the effects of both hormonal peptides, given during phase 2b of the MMC, were often stronger than those given during phase 2a, while in fasted animals the effects of CCK peptides, administered in the course of phases 2a and 2b of the MMC, were similar. Both higher doses of CCK peptides increased the number of spike bursts within the given MR pattern in the duodenum and decreased the incidence of MR mostly in the duodenal bulb. The inhibitory effects of both CCK peptides on the bulbar MR exhibited a dose-response character, though the lowest dose often evoked the slight stimulatory response. It is concluded that CCK principally exerts an inhibitory effect upon the MR in the duodenal bulb and modifies the MR in the duodenum by increasing the spike burst number in a given MR pattern. Both these actions of CCK peptides seem to be physiological. There is a positive relationship between the intensity of the refractory period and the demonstrated effect of CCK in the duodenum.
Twenty-four lactating Holstein dairy cows (12 first lactation and 12 multiparous; day in milk = 11 ± 5 days) were allotted to a randomised complete block design in a 2 × 3 factorial with four replicates per treatment to evaluate the effects of two methods of alfalfa feeding (dry and reconstituted to achieve a theoretical dry matter (DM) content of 350 g/kg) and three geometric mean (GM) particle sizes of alfalfa (9.13, 4.51 and 1.20 mm) on performance of dairy cows for a period of 28 days. Diets were offered for ad libitum intake as total mixed rations (TMR). The GM particle size, its standard deviation, and the values of physical effectiveness factor of alfalfa and TMR decreased as alfalfa particle size decreased. Reduction of particle size and reconstitution of alfalfa increased the bulk density and the functional specific gravity of alfalfa and rations. Reduction of particle size decreased insoluble dry matter, water-holding capacity, and hydration rate of alfalfa. As particle size decreased, the amount of physically effective NDF in the ration (g/kg) decreased but the daily intake of physically effective NDF (kg/day) increased. Reduction of particle size and reconstitution increased dry matter intake (DMI) and ruminal passage rate, but reduced NDF and ash digestibilities, ruminal pH, N-NH3, milk fat, total chewing activity, rumination and eating time, total and ruminal mean retention time, and time delay of marker. Increased functional specific gravity, from reduced forage particle size and the reconstitution of alfalfa, was the most important factor influencing DMI, milk composition, and chewing activity.
The objective of this study was to compare growth performance and carcass and meat quality characteristics of growing–finishing pigs fed diets containing Roundup Ready wheat (MON 71800), compared with the non-transgenic genetically similar parental control wheat (MON 71900), and four commercial varieties of non-transgenic wheat (HANK, Westbred 926, Express and Zeke). The study was carried out as a split-plot design with a 2 × 6 factorial arrangement of treatments (two genders and six wheat varieties). A three-phase dietary program was used; all diets were formulated with a fixed level of wheat inclusion (70%, 80% and 85% for the Grower, Finisher I and Finisher II phases, respectively). A total of 240 commercial hybrid pigs (equal numbers of barrows and gilts) were grown from 29.5 ± 0.29 to 114.5 ± 2.23 kg live weight in single-gender pens (barrows or gilts) of five pigs (eight pens per dietary treatment) with ad libitum access to feed and water throughout the study. At the end of each dietary phase and of the test period, ultrasound measurements were taken at the 10th rib. Animals from the transgenic (MON 71800) and non-transgenic (MON 71900) treatments were harvested at the end of the study and carcass and meat quality measurements were taken. Pigs fed the six wheat varieties had similar (P > 0.05) feed intake, live weight gain, gain : feed ratio and ultrasound measures of backfat thickness and longissimus muscle area. There was a wheat variety × gender interaction (P < 0.05) for longissimus fat content. Gilts fed the transgenic wheat had higher (P < 0.05) longissimus fat content than those fed the non-transgenic control wheat; however, for barrows there was no effect (P > 0.05) of wheat variety on longissimus fat content. However, there was no effect (P > 0.05) of wheat variety on other longissimus muscle quality or composition measures. Gilts had lower (P < 0.01) feed intake, growth rate and backfat thickness, and similar gain : feed ratio (P > 0.05) compared to barrows. This study, with growing–finishing swine, suggests that the Roundup Ready wheat (MON 71800) resulted in equivalent animal performance to conventional wheat.
In many equestrian pursuits such as dressage and show-jumping, it is important that the horse exhibits the same level of balance when ridden to the left as when ridden to the right in canter – that is, to show no motor bias. It is a long-held belief within such disciplines that to reduce bias that exists in horses and thus to enhance symmetry of performance to the left and right, the horse needs to be worked equally in both directions, although there is a lack of scientific evidence of this influencing bias. There also is little compelling evidence for either the existence or absence of motor bias in unridden (and therefore younger) or ridden (and therefore older) horses. In this study, we tested whether there was a difference in motor bias between unridden (n = 15) and ridden (n = 15) horses when their balance was challenged by cantering them in circles both to the left and to the right on the lunge. As indicators of a difference in balance between the left and right and thus as indicators of motor bias, we conducted three lunging tests – time spent in canter, whether the horse cantered on the correct lead and whether it became disunited. A grazing stance test, where the extended foreleg during grazing was recorded as the preferred forelimb, was also used to compare responses in a test where balance was not actively challenged, to the three lunging tests where balance was actively challenged. No bias was found in either the unridden or ridden groups when their balance was challenged, but ridden horses exhibited a motor bias in grazing stance – when their balance was not challenged. There was also a correlation between the responses in all three lunging tests, but none between the grazing stance test and any of the three lunging tests. We therefore conclude that neither ridden nor unridden horses are biased when their balance is challenged; thus it cannot be concluded that ambidextrous training affects an inherent bias, and that estimation of motor bias in horses is affected by the test conditions. Finally, if ridden horses are truly unbiased, strong human motor bias might be responsible for the common perception amongst riders that horses are biased.
The aim of the present study was to investigate the daily measured traits milk yield, water intake and dry matter intake with fixed and random regression models added with different error covariance structures. It was analysed whether these models deliver better model fitting in contrast to conventional fixed and random regression models. Furthermore, possible autocorrelation between repeated measures was investigated. The effect of model choice on statistical inference was also tested. Data recording was performed on the Futterkamp dairy research farm of the Chamber of Agriculture of Schleswig-Holstein. A dataset of about 21 000 observations from 178 Holstein cows was used. Average milk yield, water intake and dry matter intake were 34.9, 82.4 and 19.8 kg, respectively. Statistical analysis was performed using different linear mixed models. Lactation number, test day and the parameters to model the function of lactation day were included as fixed effects. Different structures were tested for the residuals; they were compared for their ability to fit the model using the likelihood ratio test, and Akaike’s and Bayesian’s information criteria. Different autocorrelation patterns were found. Adjacent repeated measures of daily milk yield were highest correlated (p1 = 0.32) in contrast to measures further apart, while for water intake and dry matter intake, the measurements with a lag of two units had the highest correlations with p2 = 0.11 and 0.12. The covariance structure of TOEPLITZ was most suitable to indicate the dependencies of the repeated measures for all traits. Generally, the most complex model, random regression with the additional covariance structure TOEPLITZ(4), provided the lowest information criteria. Furthermore, the model choice influenced the significance values of one fixed effect and therefore the general inference of the data analysis. Thus, the random regression + TOEPLITZ(4) model is recommended for use for the analysis of equally spaced datasets of milk yield, water intake and dry matter intake.
The effect of temperature level (24°C, 28°C, 32°C or 36°C) on performance and thermoregulatory response in growing pigs during acclimation to high ambient temperature was studied on a total of 96 Large White barrows. Pigs were exposed to 24°C for 10 days (days −10 to −1, P0) and thereafter to a constant temperature of 24°C, 28°C, 32°C or 36°C for 20 days. Pigs were housed in individual metal slatted pens, allowing a separate collection of faeces and urine and given ad libitum access to feed. Rectal (RT) and cutaneous (CT) temperatures and respiration rate (RR) were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. From day 1 to 20, the effect of temperature on average daily feed intake (ADFI) and BW gain (average daily gain, ADG) was curvilinear. The decrease of ADFI averaged 90 g/day per °C between 24°C and 32°C and 128 g/day per °C between 32°C and 36°C. The corresponding values for ADG were 50 and 72 g/day per °C, respectively. The 20 days exposure to the experimental temperature was divided in two sub-periods (P1 and P2, from day 1 to 10 and from day 11 to 20, respectively). ADFI was not affected by duration of high-temperature exposure (i.e. P2 v. P1). The ADG was not influenced by the duration of exposure at 24°C and 28°C groups. However, ADG was higher at P2 than at P1 and this effect was temperature dependent (+130 and +458 g/day at 32°C and 36°C, respectively). In P2 at 36°C, dry matter digestibility significantly increased (+2.1%, P < 0.01); however, there was no effect of either duration or temperature on the digestibility of dry matter at group 24°C and 32°C. RT, CT and RR were measured three times daily (0700, 1200 and 1800 h) every 2 to 3 days during the experiment. Between 28°C and 36°C, RT and CT were lower during P2 than during P1 (−0.20°C and −0.23°C; P < 0.05), whereas RR response was not affected by the duration of exposure whatever the temperature level. In conclusion, this study suggests that the effect of elevated temperatures on performance and thermoregulatory responses is dependent on the magnitude and the duration of heat stress.