bluuebunny/crossref_metadata_2025 huggingface dataset:
Follicular waves are associated with transient fluctuations in FSH but not oestradiol or inhibin-A concentrations in anoestrous ewes
Authors: Evans A.C.O. , Duffy P. , Quinn K. M. , Knight P. G. , Boland M. P.
Published: August 2016

The aim was to examine statistically the changes among days in the numbers of follicles relative to the growth of large follicles to test the hypothesis that follicular development occurs in a wave-like fashion in anoestrous ewes. The relationships among the patterns of circulating concentrations of FSH, oestradiol and inhibin-A and the pattern of follicular growth as well as relationships among follicular fluid steroid and inhibin-A concentrations were also studied. The ovaries of 11 ewes were examined daily using transrectal ultrasonography for 14 days and blood samples were collected every 8 h for 9 days. Five ewes were ovariectomized on the last day of ultrasound scanning. One to three identified follicles (a cohort) emerged every 2 to 5 days (mean 2·9 (s.e. 0·2) days) in individual ewes. The numbers of 4 and 5 mm follicles were fewest (P < 0·05) before and greatest (P < 0·05) 1 day after cohort emergence. This change in the numbers of follicles indicates a wave-like pattern of follicular growth. FSH concentrations were greatest (P < 0·05) on the day before wave emergence and lowest (P < 0·05) on the day of wave emergence. Peripheral concentrations of oestradiol and inhibin-A did not fluctuate (P > 0·05) in association with the emergence of follicular waves. The follicles that were collected at ovariectomy originated from one of three different waves. Oestradiol and inhibin-A concentrations in follicular fluid and the oestradiol-to-progesterone ratio were not different among the largest follicles of successive waves, when follicles were collected at the same time, indicating that new waves of follicles developed before the demise of old waves.

In conclusion, waves of follicles emerged about every 3 days in anoestrous ewes (defined as significant changes in numbers of follicles) and were associated with fluctuations in FSH concentrations but not peripheral oestradiol or inhibin-A concentrations. New follicular waves also emerged in the presence of steroidogenically active (positive oestradiol-to-progesterone ratio), inhibin-A producing follicles from a previous wave suggesting that follicles do not exert functional dominance during the non-breeding season.
Genotype-related variations in subcutaneous fat composition in sheep
Authors: Mezöszentgyörgyi D. , Husvéth F. , Lengyel A. , Szegleti C. , Komlósi I.
Published: August 2016

The aim of this research was to study the effect of genotype on the fatty acid composition in adult ewes and 5-to 6-month-old lambs of two mutton breeds (Suffolk and Pannon Sheep) and Booroola Merino. Samples of subcutaneous fat were obtained by surgical biopsy around the tailhead. Fatty acid composition of the adipose fat was determined by gas chromatography. Significant differences (P< 0·05) were found in the fatty acid composition of the adipose tissue among the three breeds. Suffolk showed a lower (P< 0·05) proportion of C12: 0 and C14: 0 fatty acids than the other two breeds. Considering the total quantity of saturated (TSFA) and the total quantity of unsaturated (TUFA) fatty acids, Booroola Merino showed a significantly (P< 0·05) higher proportion of TSFA and lower proportion of TUFA in their adipose tissue than the mutton genotypes (Suffolk and Pannon Sheep). Higher proportions of C18: 0, C18: 3 and C20: 1 (P< 0·05) but lower proportions of C12: 0, C14: 0, C16: 0, C16: 1 and C18: 2 (P< 0·05) were found in the subcutaneous fat of adult ewes than in that of their female progeny. Sex differences were also observed in the study. The proportions of saturated fatty acids were higher (P< 0·05) in female lambs than in males of the same age. These results indicate that a genetic approach may be useful to improve fatty acid composition of carcass lipids in sheep. However, age and sex differences also have to be taken into consideration.
Influence of growth rate and muscle type on muscle fibre type characteristics, protein synthesis capacity and activity of the calpain system in Friesian calves
Authors: Therkildsen M. , Melchior Larsen L. , Vestergaard M.
Published: August 2016

The objective of this study was to determine the effect of growth rate on muscle fibre characteristics, concentration of nucleic acids (RNA and DNA) as indicators of muscle protein synthesis capacity and activity of the calpain system at time of slaughter in m. longissimus lumborum (LL) and m. supraspinatus (SS) from calves, in order to elucidate the effect of growth rate on muscle protein turn-over at time of slaughter. Twenty-four Friesian heifer calves were allocated to two different feeding regimens that allowed for a moderate/moderate (MM) or high/high (HH) growth rate from 5 days of age to 90 kg body weight (BW) (period I) and from 90 kg BW to slaughter at 250 kg BW (period II), respectively. The growth rates in the two periods and the weight of LL and SS at slaughter were recorded. Within 30 min after exsanguination, samples were removed from LL and SS, snap-frozen, and later analysed for muscle fibre type frequency and cross-sectional area, DNA and RNA concentration and the activity of the calpain system. High growth rate (i.e. 895 g/day and 1204 g/day in periods I and II, respectively), compared with moderate growth rate (678 g/day and 770 g/day in periods I and II, respectively) had a marked effect on muscle weight and muscle characteristics. High compared with moderate growth rate resulted in hypertrophic growth of type I, IIA and IIB fibres in LL and of type IIA and type IIB fibres in SS, but had no effect on the muscle fibre type frequency in either of the muscles. High growth rate increased total DNA and RNA content and the RNA: DNA ratio in LL, indicating a greater potential for protein synthesis in this muscle, whereas the effect of growth rate was smaller in SS. The activity of µ-calpain, m-calpain and calpastatin was higher in the red SS muscle compared with the whiter LL muscle. However, these enzyme activities were not affected by growth rate, and thus, did not indicate a higher myofibrillar proteolysis in vivo in calves exhibiting high growth rate compared with moderate growth rate. Overall the results showed that different types of muscles react differently to high versus moderate growth rate. High growth rate induced muscle hypertrophy and increased protein synthesis capacity especially in LL and less in SS, but the activities of the enzymes in the calpain system did not show any concomitant increase in muscle protein degradation that would be in favour of improved meat tenderness.
Effect of dietary electrolyte balance on metabolic rate and energy balance in pigs
Authors: Dersjant-Li Y. , Schrama J. W. , Heetkamp M. J. W. , Verreth J. A. J. , Verstegen M. W. A.
Published: August 2016

The effect of two dietary electrolyte balance (dEB, Na+ + K+ – Cl-) levels (–135 and 145 mEq/kg diet) on heat production, energy and nitrogen retention in piglets was assessed. The experiment consisted of a 13-day adaptation period and a 7-day balance period in two open-circuit climate respiration chambers. Nine groups of three (4 weeks old) crossbred barrows were assigned to one of two diets (five and four groups for –135 and 145 mEq/kg dEB diets respectively). During the balance period, diets were provided at 2·3 times the energy requirement for maintenance in two equal meals daily. Total heat production for each group was determined every 9 minutes from the exchange of CO2 and O2. Faeces and urine mixture was quantitatively collected during the balance period to measure energy and nitrogen balance. Total heat production and metabolizable energy costs for maintenance tended (P 0·10) to be higher in the 145 mEq/kg dEB group (681 and 443 kJ/kg0·75 per day respectively) than in the –135 mEq/kg dEB group (660 and 412 kJ/kg0·75 per day respectively). Differences in total heat production between the two dEB groups mainly occurred in the daytime (light period), when significance level was P 0·01. The respiratory quotient and energy retention as fat were numerically (but not statistically significantly) lower in the 145 mEq/kg dEB group compared with –135 mEq/kg dEB. In conclusion, energy balances were similar for both treatments. However in the daytime (light period), piglets needed more energy for maintenance after ingesting a diet with a dEB level of 145 mEq/kg compared to a diet with a dEB level of –135 mEq/kg at a restricted feeding level.
Effects of the α2-adrenoceptor agonist, guanfacine, on growth rate, glucose, corticosterone, insulin and energy partitioning in rats
Authors: Gazzola C. , Spiers W. G.
Published: August 2016

In experiment 1, female Wistar rats (no. = 24) with free access to food were treated daily for 8 days with subcutaneous injections of saline or 0·5 mg/kg of the α2-adrenoceptor agonist, guanfacine hydrochloride. In experiment 2, female Wistar rats (no. = 24), restricted to 12 g food per day were treated daily for 45 days with subcutaneous injections of 1 μl/g body weight saline containing 0, 0.001, 0.025 or 0·5 mg/kg guanfacine hydrochloride. In experiment 1, the control and treated groups consumed similar amounts of food but the guanfacine-treated animals gained less body weight (P 0.05) and less muscle mass (P 0.01). The treated animals had pronounced glucosuria (P < 0.05) during the whole treatment period. At slaughter, the treated group had higher blood glucose (P < 0.001) and serum corticosterone (P < 005) but insulin concentrations were not different. In experiment 2, only the 0.5 mg/kg dose of guanfacine had significant effects. Resting oxygen consumption on day 29 of treatment was proportionately 0.10 lower in this group compared with controls (P < 0.05). There was no effect of treatment on growth rate. After 46 days, the 0·5 mg/kg treatment group had proportionately 0·35 more body fat (P < 0.01), higher body fat content (P < 0.01), higher total body energy (P < 0.05) and higher total body energy content (P < 0.05). Experiment 1 linked reduced growth rate with increased corticosterone concentrations and experiment 2 suggested the mechanism may be a repartitioning of energy storage to lipid. However, it was not determined whether these consequences were a direct effect of guanfacine or a secondary effect due to corticosterone. In spite of reductions in energy expenditure, guanfacine retards growth in rats and mice, but not in cattle where growth is enhanced. Thus rodents may have a limited usefulness as models for studies of α2-adrenoceptor agonists in cattle.
Differentiationin vitroof omental and subcutaneous pre-adipocytes from Spanish Lacha and Rasa Aragonesa sheep
Authors: Arana A. , Vernon R. G. , Eguinoa P. , Soret B. , Mendizabal J. A. , Purroy A.
Published: August 2016

Factors responsible for breed- and depot-specific differences in the development of lipogenic enzymes, and hence lipogenic capacity of adipocytes, in sheep adipose tissue have been investigated using a serum-free cell culture system. Effects of insulin, tri-iodothyronine and exogenous lipid on the development in vitro of the lipogenic enzymes glycerol 3-phosphate dehydrogenase (G3PDH), fatty acid synthetase (FAS), NADP-malate dehydrogenase (ME), glucose 6-phosphate dehydrogenase (G6PDH), and isocitrate dehydrogenase (ICDH) in omental and subcutaneous pre-adipocytes from Lacha and Rasa Aragonesa lambs were investigated. Addition of insulin plus tri-iodothyronine caused pre-adipocyte differentiation, which was enhanced by addition of a lipid supplement. G3PDH activities achieved by differentiation of pre-adipocytes in vitro were similar to those found in vivo; furthermore after differentiation in vitro adipocytes from Rasa Aragonesa lambs had a greater G3PDH activity than adipocytes from Lacha lambs, as found in vivo. In contrast activities of FAS, G6PDH and ME achieved by differentiation in vitro were much greater than those found previously in vivo. While breed- and depot-specific changes in G6PDH observed after differentiation in vitro were similar to those observed in vivo, changes in FAS induced in vitro differed from those found during development in vivo. The study shows that pre-adipocytes from Rasa Aragonesa and Lacha lambs have intrinsic depot- and breed-specific differences in their ability to differentiate and express lipogenic enzymes. The combination of insulin, tri-iodothyronine and a lipid supplement appears to be sufficient to account for in vivo G3PDH activities but other factors are required to explain activities of FAS, G6PDH and ME found in vivo.
Influence of dietary fibre on digestive utilization and rate of passage in growing pigs, finishing pigs and adult sows
Authors: Goff G.Le , Milgen J. van , Noblet J.
Published: August 2016

Four experimental diets differing in the level and the origin of dietary fibre (DF) were studied: a control, low DF diet (diet C, 100 g total dietary fibre (TDF) per kg dry matter (DM)) and three fibre-rich diets (200 g TDF per kg DM) which corresponded to a combination of diet C and maize bran (diet MB), or wheat bran (diet WB), or sugar-beet pulp (diet SBP). During two successive experimental periods, each diet was offered to five pigs at a growing stage (35 kg body weight (BW)) and at a finishing stage (75 kg BW). In addition, four adult ovariectomized sows received successively one of the four diets according to a 4 ✕ 4 Latin-square design. Digestive utilization of energy and nutrients of diets and rate of passage parameters were determined using a pulse dose of ytterbium oxide followed by total faecal collection. Faecal marker excretion was quantified using an age-dependent, one-compartment model, from which the mean retention time in the gastrointestinal tract of pigs (MRT) was obtained. The digestibility of dietary energy and nutrients, especially the DF fraction, increased with the increase in BW from growing to finishing pigs (P < 0.01) and was still higher in adult sows; the difference between pig stages was more pronounced for diet MB. At each stage, the digestibility of energy or nutrients was lower (P < 0.01) for diets MB or WB than for diet SBP. Accordingly, the energy and DF digestibility of sugar-beet pulp was higher and increased much less with BW. The MRT was shorter for diets MB and WB in growing pigs and in sows. Sows had a longer MRT (81 h) than finishing pigs (37 h) and growing pigs (33 h); however, MRT was highly variable between sows. It is concluded that the degree to which different types of DF are digested depends, in part, on the botanical origin, and it may be improved by a longer MRT in the gastrointestinal tract of pigs. Some fibrous foodstuffs (such as maize-by products) will benefit more from a longer MRT than others.
Ovarian follicular dynamics and endocrine profiles in Polwarth ewes with high and low body condition
Authors: Viñoles C. , Harris L. J. , Forsberg M. , Banchero G. , Rubianes E.
Published: August 2016

In this investigation we tested the hypothesis that static body condition (BC) of the ewe affects oestradiol and FSH with implications for subsequent follicular growth and turn-over. Sixteen Polwarth ewes were selected from a flock according to their BC score (scale: 1 emaciated; 5 obese). High BC (HBC) ewes (no. = 8) had a BC score of 4·1 (s.e. 0·1) and low BC (LBC) ewes (no. = 8) had a BC score of 1·9 (s.e. 0·1). Daily ultrasound examinations were performed and blood samples for progesterone, oestradiol and follicle-stimulating hormone (FSH) determination were collected. All HBC ewes (8/8) exhibited three waves of follicular development, while four LBC ewes (4/8) had two waves and the other four (4/8) had three waves of follicular development (P ≤ 0·05) during the interovulatory period. Overall, the emergences of 33 out of 44 follicular waves were preceded by significant increases in FSH concentrations. Maximum FSH concentrations were detected 0·9 ± 0·2 days before wave emergence. Oestradiol concentrations increased significantly during the growing phase in 38 out of 44 large follicles. A negative correlation between oestradiol and FSH was observed in HBC ewes. A similar inhibitory effect of oestradiol on FSH was observed in LBC ewes, irrespective of whether they developed two or three follicular waves. However, a longer period with high FSH was needed to promote the emergence of the second follicular wave in two-wave LBC ewes. Four HBC ewes had twin ovulations but no LBC ewes did (P ≤ 0·05). In HBC ewes, the follicular phase was characterized by lower oestradiol (6·5 (s.e. 1·0) pmol/l) but higher mean FSH concentrations (2·4 (s.e.0·4) μg/l) than in LBC ewes (8·9 (s.e. 1·2) pmol/l and 2·0 (s.e. 0·3) μg/l, respectively; P ≤ 0·05). The present results suggest that BC influences the pattern of follicular dynamics through changes in the endocrine milieu. Higher FSH concentrations during the follicular phase in HBC ewes, which allowed an extended period of follicular recruitment from a significantly larger pool of small antral follicles could explain the higher ovulation rate observed in this group.
Choline requirements of grass shrimp(Penaeus monodon)as affected by dietary lipid level
Authors: Shiau S. Y. , Cho W. H.
Published: August 2016

A feeding trial was conducted to determine the adequate level of dietary choline for juvenile grass shrimp, Penaeus monodon, given diets containing different dietary lipid concentrations. Purified diets with six levels of choline chloride (0, 2000, 5000, 8000, 11000 and 14000 mg/kg diet) at either 50 or 110 g/kg lipid concentration were each given to three replicate groups of 15 shrimp (mean weight: 0·88 (s.d. 001) g) for 8 weeks. Results indicated that in the 50 g/kg lipid group, weight gain was highest in shrimp given the diets supplemented with 5000 mg choline per kg diet, intermediate in the group given 8000 mg choline per kg diet and lowest in the 14000 mg choline per kg diet and the unsupplemented control groups (P < 005); food efficiency (FE) was highest in shrimp given 5000 mg choline per kg diet, followed by the groups given > 8000 mg choline per kg diet and lowest for the unsupplemented control group. In the 110 g/kg lipid group, weight gain was highest in shrimp given the diets supplemented with 5000 and 8000 mg choline per kg diet, intermediate in the groups given 2000 and 14000 mg choline per kg diet and lowest in the control group; FE was higher in shrimp given 8000 mg choline per kg diet than in any of the other dietary groups; hepatic lipid concentration was higher in shrimp given < 2000 mg choline per kg diet than shrimp given > 5000 mg choline per kg diet. In both lipid groups, shrimp given < 2000 mg choline per kg diet had higher hepatosomatic index (HSI) than shrimp given > 5000 mg choline per kg diet. Of shrimp given <2000 mg choline per kg diet, those in the 110 g/kg lipid group had higher HSI and hepatic lipid concentration than those in the 50 g/kg lipid group. Analysis by polynomial regression of weight gain indicated that the optimum dietary choline requirements in juvenile grass shrimp were about 6400 mg/kg diet and 7800 mg/kg diet in 50 and 110 g/kg lipid diets, respectively.
Ovulation of the first dominant follicle arising after day 21post partumin suckling beef cows
Authors: Sinclair K. D. , Molle G. , Revilla R. , Roche J. F. , Quintans G. , Marongiu L. , Sanz A. , Mackey D. R. , Diskin M. G.
Published: August 2016

The effects of body condition score (BCS) of 2·0 or 3·0 units at calving (low v. moderate), post-partum energy intake at 0·6 or 1·0 MJ metabolizable energy (ME) per day per kg M0·75 (low v. high) and unrestricted or restricted (once daily) suckling on the ability of cows to ovulate were studied in a 2 ✕ 2 ✕ 2 factorial design with each treatment replicated eight times. Calf isolation and restricted suckling were imposed shortly after selection of the first dominant follicle (DF) to emerge after day 21 post partum. The episodic release of LH (sampled at 15-min intervals for 10 h) was determined 48 h before and 48 h after the day calf isolation and restricted suckling commenced. Additional blood samples were collected weekly for plasma insulin determination. The mean interval from calving to first ovulation was shorter for cows in moderate than low BCS at calving (47·8 v. 57·1 days, s.e.d. = 4·50, P < 0·05), and for cows suckling once daily than for those with unrestricted suckling (42·9 v. 62·0 days, s.e.d. = 4·50, P < 0·001). Post-partum nutrition did not affect this interval. Mean LH pulse frequency prior to the start of restricted suckling was higher for cows of moderate than low BCS at calving (3·2 v. 1·6 pulses per 10 h, s.e.d. = 0·60, P < 0·05). Subsequently, LH pulse frequency was higher for cows suckling once daily than for those with unrestricted suckling (4·0 v. 2·2 pulses per 10 h, s.e.d. = 0·82, P < 0·05). More cows in moderate than low BCS ovulated the first DF to emerge after day 21 post partum (within 4 to 6 days) in response to restricted suckling (69 v. 25%, P < 0·05). LH pulse frequency prior to restricted suckling increased (P < 0·05) with plasma insulin concentration (categorized as low, < 5; moderate, 5 to 8; and high, >8 mIU per l). There were indications of interactions between suckling treatment and BCS (P < 0·08), and suckling treatment and plasma insulin concentration (P < 0·06), on LH pulse frequency, which suggested that calf restriction could alleviate the suppressive effects of under nutrition on episodic LH release. Amongst cows suckling once daily, the non-ovulating animals had fewer LH pulses prior to restricted suckling and smaller, slower growing DF, indicating an inability of the DF to respond to increased LH pulse frequency following calf restriction. Cows of moderate BCS, particularly those with moderate to high levels of plasma insulin (³ 5 mIU per l), responded favourably to restricted suckling. In contrast, excessively thin cows with low plasma insulin concentrations (<5 mIU per l), that had most to gain from restricted suckling, responded poorly.
Effect of type of supplement offered out of parlour on grazing behaviour and performance by lactating dairy cows grazing continuously stocked grass swards
Authors: Gibb M. J. , Huckle C. A. , Nuthall R.
Published: August 2016

Two 4-week experiments were conducted to examine the effect of type of supplement, offered through automatic feeders at pasture, on supplement intake and grazing behaviour by multiparous spring-calving Holstein-Friesian cows grazing continuously stocked grass pastures. Four supplement formulations were used: a dairy concentrate containing 180 g crude protein per kg fresh weight (treatment DC), a high digestible undegraded protein supplement (treatment HP), a high starch, low protein supplement (treatment HS) and a high fibre supplement (treatment HF). In experiment 1, groups of eight cows were provided with access to one of diets DC, HP or HS, with a maximum of 4 kg being available during each of two periods, between 16:00 and 03:30 h and between 03:30 and 14:30 h. During experiment 2, groups of eight cows were provided access to diet DC, HP, HS or HF, up to a maximum of 8 kg between 16:00 and 14:30 h the following day. Detailed measurements of grazing, ruminating and supplement eating behaviour were made using jaw movement recorders and the transponder-controlled out-of-parlour feeder software. Treatment had no effect on intake rate per min or daily intake of supplement in either experiment, but did affect the temporal pattern of concentrate meals. Treatment did not affect grazing bite mass, bite rate or intake rate in either experiment. During experiment 1, compared with treatment DC, treatment HS reduced total eating time, total grazing jaw movements and daily herbage intake and increased ruminative mastications per bolus and ruminative mastications per kg grass OM intake. In experiment 2, compared with treatment DC, only treatment HS reduced total eating time, total grazing jaw movements and daily herbage intake. Treatments HS and HF both increased ruminative mastications per bolus. The results indicate that when supplements are available at pasture there is a conflict between the time required to consume supplements and herbage and that supplement type can affect both the temporal pattern of supplement intake and subsequent grazing activity.
Out-wintering pads for finishing beef cattle: animal production and welfare
Authors: Hickey M. C. , French P. , Grant J.
Published: August 2016

The objective of this experiment was to evaluate the performance and well being of animals accommodated outdoors over the winter period on out-wintering pads (OWPs), relative to animals housed indoors in conventional slatted floor sheds. One hundred and twenty-six steers were assigned at random to one of seven treatments. The first six treatments were accommodated on OWPs. These six treatments were arranged in a three (6, 12 and 18 m2 per head space allowance) by two (wind sheltered or exposed) factorial design. A seventh treatment group (control) was housed indoors in a slatted-floor shed at a space allowance of 3 m2 per head. All animals were offered silage ad libitum and 5 kg concentrate per day. All animals were slaughtered at the end of the 151 day experiment. Animal production and indices (climatic energy demand (CED), behaviour, cleanliness, hoof condition and immune function) of animal welfare were evaluated. There was no significant effect of stocking density outdoors or sheltering on live-weight gain, carcass gain, fat score, fat score per 100 kg carcass, kidney plus channel fat (KCF) as a proportion of carcass, carcass conformation score, killing-out proportion, food intake or food efficiency. Relative to animals housed indoors on slats, animals accommodated outdoors on OWPs had higher daily live-weight gain (F < 0·001), carcass gain (F < 0·05), and food intake (F < 0·05). However, animals on the OWPs had less KCF per kg carcass and lower fat scores per 100 kg carcass. There was no effect of shelter on the CED of animals out-wintered, which was higher (P < 0·001) than their counterparts wintered indoors on slats. Animals housed on slats were cleaner than animals housed at 6 or 12 m2 per head (F < 0·05) but not 18 m2per head. There was no effect of treatment on physiological measures. Animals confined on the OWP with or without shelter, had a greater number of lying bouts per 24 h (F < 0·076), had a greater synchronized lying frequency (F < 0·082) and displayed less hesitation prior to lying when compared with animals housed on slats. Indoor animals had more white line disease (F < 0·01) and under-run (F < 0·001) on their front hoof, when compared with outdoor animals. Animals accommodated outdoors at 18 m2per head had more (F < 0·05) claw erosion while the indoor animals had a greater (F < 0·001) degree of under-run present on their hind hoof. There was no evidence to suggest that out-wintering compromised animal welfare. Further studies are required to determine the reason for the increased carcass growth and leanness of the cattle on the OWPs.
Comparison of the productivity of Texel and Rouge de l’Ouest ewes and their crosses
Authors: Dawson L. E. R. , Carson A. F. , McClinton L. O. W.
Published: August 2016

An experiment was undertaken to compare the productivity of crossbred ewes, produced by crossing Texel sires with Rouge de l’Ouest (Rouge) dams and Rouge sires with Texel dams, relative to purebred Texel and Rouge ewes. The purebred and crossbred ewes were crossed with Rouge and Texel sires. The proportion of productive ewes was similar in the purebred and crossbred ewes with an average figure of 0·92. Irrespective of crossing sire, Rouge ewes produced 0·48 more lambs per ewe lambed than Texel ewes (P < 0·001). The two crossbred ewe types (Texel ✕ Rouge and Rouge ✕ Texel) each produced similar numbers of lambs (on average 1·92 lambs per ewe lambed). Individual heterosis values for ewe fertility and prolificacy were small and not significant (–1·67 for the proportion of productive ewes and –3·14 for the number of lambs born per ewe lambed). Maternal heterosis values were also not significant but were of larger magnitude (6·26 for ewe fertility and 3·12 for prolificacy). Lamb mortality (number of lambs born dead per ewe lambed) at birth was similar for purebred Rouge (0·44) and Texel (0·30) ewes and was significantly reduced by crossbred matings and mating the crossbred ewes (individual heterosis –30·68, P < 0·10; maternal heterosis –80·23, P < 0·001). Individual and maternal heterosis values for lamb growth rate from birth to six weeks were 8 (P < 0·05) and 4 (P > 0·05) respectively. Lamb growth rate from birth to weaning was significantly lower in lambs from Texel ewes compared with those from the other genotypes (P < 0·05). Individual and maternal heterosis values for live-weight gain from birth to weaning were 5 (P < 0·10) and 5 (P < 0·01). The results of the current study demonstrate the superior performance of purebred Rouge ewes compared with purebred Texel ewes in terms of prolificacy and lamb growth rate from birth to weaning. However, both breeds had high lamb mortality at birth. Crossbreeding led to the production of hybrid ewes which had relatively high prolificacy with low levels of dystocia and lamb mortality.
A comparison of the effects on voluntary intake by sheep of either dietary or intra-ruminal addition of silage juices
Authors: Offer N.W.
Published: August 2016

Two silages were made from a regrowth of perennial ryegr ass following a 24-h wilt using either 2·5 l/t (LF) or 5·5 l/t (HF) of Add Safe (an aqueous solution of ammonium tetraformate, Trouw Nutrition, Cheshire, UK). Composition of silages LF and HF respectively were for dry matter (DM, g/kg) 205, 217; crude protein (g/kg DM) 106, 104; digestible organic matter (g/kg DM) 665, 692, pH 3·8, 3·9; lactic acid (g/kg DM) 103, 84; neutralizing value (meq/kg DM) 1051, 892; acetic acid (g/kg DM) 18·4, 14·0. Experiment A measured the intakes of the two silages using 12 Scottish Blackface wether lambs (mean live weight 25 kg) using a cross-over design with periods of 21 days. Intakes (g DM per day) were significantly greater (P < 0·05) for silage HF (329) than for LF (268). Experiment B measured the voluntary intakes of dried silage residues following juice extraction using the same protocol as for experiment A, except that only six lambs were used. There were no significant differences in composition or intake (P > 0·05) of the dried residues from the two silages. Experiment C used a 5 × 5 Latin-square design to measure the effects on voluntary intake of adding juices from the two silages to unmolassed sugar-beet nuts (SBN) pre-feeding or administered directly into the rumen in two discrete doses per day. Sheep on treatments LED and HFD received juices added to SBN (1·5 l/kg) and water added into the rumen in equal volume to the juice consumed with the previous day’s SBN. Treatments LFR and HFR received water added to the SBN (1·5 l/kg) and juice into the rumen in equal volume to the water consumed with the previous day’s SBN. The control treatment (W) was water added both to the SBN and into the rumen. Total mean daily intakes (g/day) were 1930,1954,1296, 2034 and 1703 (s.e.d. 179) for treatments LED, HFD, LFR, HFR and W respectively. Treatment LFR gave significantly lower mean daily intakes (P < 0·05) than all other treatments. Values for pH, volatile fatty acids and ammonia in the rumen fluid were not significantly affected by treatment (P > 0·05). Differences in voluntary intake for the two silages made from the same crop using different ensilage methods were attributed to differences in the silage liquid and volatile phases and not to the non-volatile solid phase. The effects of juice composition on intake were greater when added directly to the rumen than when added to the diet suggesting that effects on taste or smell were relatively unimportant.
The effects of plane of nutrition and diet type on metabolic hormone concentrations, growth and milk production in high genetic merit dairy herd replacements
Authors: Carson A.F. , Wylie A.R.G. , McEvoy J.D.G. , McCoy M. , Dawson L.E.R.
Published: August 2016

Seventy high genetic merit Holstein heifers were used in two experiments to investigate (1) the effects of plane of nutrition and diet type during the pre-pubertal period and (2) the effects of plane of nutrition during the post-pubertal period on metabolic hormone concentrations, growth and milk production. In experiment 1, treatment 1 and 2 heifers were given food to achieve a live-weight gain of 0·70 and 0·95 kg/day from 3 to 10 months of age on a grass silage based diet, while treatment 3 heifers were given food to achieve 0·95 kg/day on a barley straw/concentrate diet. During the pre-pubertal period, heifers reared on treatment 1 had significantly higher growth hormone(GH) concentrations (ng/ml per 1 h) than heifers reared on treatment 2 (P < 0·01) and had significantly lower insulin concentrations than heifers reared on treatment 3 (P < 0·01). Heifers reared on treatment 1 had significantly lower insulin-like growth factor 1 (IGF-1) concentrations than those reared on treatment 3 (P < 0·01). At 10 months of age heifers reared on treatment 1 were of lower condition score (P < 0·01) than those on treatment 2 and had a smaller heart girth diameter (P < 0·01) than those on treatments 2 and 3. During the first lactation, milk yield and composition produced by the heifers was not significantly affected by treatment. In experiment 2, treatment A heifers were given, from 14 to 24 months of age, a low plane of nutrition to allow a live-weight gain of 0·65 kg/day on a grass silage and grass based diet during the winter and summer periods respectively. Treatment B heifers were kept on a high plane of nutrition to allow a live-weight gain of 0·90 kg/day on the same forage along with concentrate supplementation. During the rearing period, GH and IGF-1 concentrations were not significantly affected by treatment. Treatment A heifers weighed less before calving (P < 0·05), had a lower condition score (P < 0·01), and had a smaller heart girth diameter (P < 0·01) than those on treatment B. During the first 10 weeks of lactation, heifers on treatment A had a higher silage dry matter intake and lost less weight (P < 0·05) than those on treatment B, however, by 20 weeks of lactation these effects had disappeared. Milk yield and composition during the first lactation were not significantly affected by treatment. Overall, the findings of experiments 1 and 2 did not show any beneficial effects of higher weights at first calving in high genetic merit Holsteins and therefore indicate that accelerated growth in the pre- or post-pubertal period may not be required.
Effect of fermented liquid food and zinc bacitracin on microbial metabolism in the gut and sensoric profile ofm. longissimus dorsifrom entire male and female pigs
Authors: Hansen L. L. , Mikkelsen L. L. , Agerhem H. , Laue A. , Jensen M. T. , Jensen B. B.
Published: August 2016

The aim of this work in pigs was to evaluate the effect of fermented liquid food (FLF) and the combination of FLF plus short-term addition of an antibiotic food additive zinc bacitracin (FLF + ZB) compared with fed non-pelleted dry food (NPDF), on microbial metabolism in the gut and the effects on flavour and odour attributes and profiles of pig meat as well as boar odour from entire male and female pigs.

At an average start weight of 60 kg, 108 pigs (54 males and 54 females) were equally allocated to three treatments according to pen-replicate, litter and sex. Microbial metabolism in the gut was studied in 24 pigs, eight from each treatment. For sensory profile evaluation (flavour, odour and tenderness) of pork loins from m. longissimus dorsi, 48 pigs (24 entire males and 24 females) were selected. The sensory evaluation of different qualities of flavour and odour as well as tenderness of cooked pork loins (LD) was done by a boar taint (skatole and androstenone) trained taste panel. To evaluate the odour and the flavour, a sensory profile analysis was performed which involved the following attributes: total off-odour/off-flavour, pig, urine, manure, naphthalene, rancid, sweet and sweat in the whole sample including both meat and fat.

Giving FLF to pigs significantly changed the microbiota in the gastro-intestinal tract compared with NPDF. In particular, the density of coliform bacteria was reduced in the gastro-intestinal tract of the pigs on FLF. Giving FLF demonstrated no effects on skatole concentration in caecum, colon, blood and backfat and boar odour attributes, whereas administration of FLF + ZB decreased the skatole concentrations and the typical boar odours, pig and manure odour, compared especially with the pigs on NPDF. However, meat from pigs given FLF either with or without zinc bacitracin had smaller but significantly worsened scores for three flavour attributes — pig flavour, rancid flavour and total off-flavour — compared with meat from NPDF pigs and the three flavour attributes were equally affected in both sexes. This seems to point to a significant worsening of meat flavour in pigs given FLF that is independent of sex and boar odour problems (skatole and androstenone).
Long-term changes in performance and meat quality of Danish Landrace pigs: a study on a current compared with an unimproved genotype
Authors: Oksbjerg N. , Petersen J. S. , Sørensen I. L. , Henckel P. , Vestergaard M. , Ertbjerg P. , Møller A. J. , Bejerholm C. , Støier S.
Published: August 2016

An experiment was conducted in 1995 in order to examine muscle growth, muscle histochemical properties, muscle metabolism and meat quality of two types of Danish Landrace pigs representing the growth potential of years 1976 and 1995, respectively. Danish Landrace pigs representing 1976 (slow-growing, SG) originated from a breeding station where the population was maintained without being selected for production traits such as daily gain, food conversion ratio and meat content. Pigs representing Danish Landrace of 1995 (fast-growing, FG) were bought from certified Danish pig breeders. The pigs were simultaneously tested for performance from 40 to 95 kg live weight. The daily gain, food conversion ratio and meat content of the carcass were improved proportionately by 0·43, 0·24 and 0·03 in FG pigs compared with SG pigs. In m. longissimus dorsi (LD), the cross-sectional area of muscle fibres was smaller in FG pigs compared with SG pigs indicating increased muscle fibre number. Data further suggest increased satellite cell proliferation in muscles of FG pigs. Serum from FG pigs stimulated the proliferation of C2C12 muscle cells to a greater extent than serum from SG pigs, although the serum level of insulin-like growth factor 1 did not differ between pig types. The effect of serum on protein turn-over of C2C12 myotubes did not depend on pig type. The glycogen concentration in the LD did not differ significantly between pig types, while the activity of citrate synthase, 3-OH-acyl-CoA-dehydrogenase, and lactate dehydrogenase were higher in the LD of SG pigs compared with FG pigs. Pork chop colour of FG pigs was proportionately 0·09 lighter (L⋆) and 0·13 less red (a⋆) than pork chops of SG pigs. The total muscle pigment concentration in the LD, m. biceps femoris and m. vastus intermedius was proportionately reduced by 0·17, 0·19 and 0·11, respectively, in FG pigs compared with SG pigs. In the LD, the concentration of myoglobin was proportionately reduced by 0·17 in FG pigs. The chemical composition of the LD differed between pig types such that the water content was higher and protein content lower in LD from FG pigs compared with SG pigs. The pH of the LD measured 45 min and 24 h post mortem, drip loss and thawing loss were similar for both pig types. Meat tenderness of conditioned pork chops of FG pigs was slightly reduced in accordance with a decreased intensity of the 31 kDa peptide band and increased cooking loss. The present study suggests that increased muscle fibre number and rate of muscle DNA deposition (satellite cell proliferation) have contributed to the increased muscle growth as a result of selection for performance in pigs under Danish conditions. However, the increase in growth performance was accompanied by deterioration in muscle colour and slightly reduced tenderness.
Quantitative analysis of methionine and cysteine requirements for wool production of sheep
Authors: Liu S. M. , Masters D. G.
Published: August 2016

The conventional system of estimating metabolizable protein requirement is unsuitable for defining amino acid requirements because nitrogen loss cannot be converted to amino acid loss, and because there is a lack of data on the utilization efficiencies of individual amino acids for various productive purposes. Therefore, we are proposing an alternative approach. In this review, we use methionine (Met) and cysteine (Cys) for wool production in sheep as examples, and define requirement as retention in both body and wool protein, plus the amount of obligatory oxidation that accompanies the retention. The requirements are expressed in terms of the net absorption. Mathematical models for the calculation of the requirements of both amino acids are established based on the level of absorption, endogenous contribution from body protein breakdown, oxidation rates and the amino acid composition of body and wool proteins. The flows and oxidation of Met and Cys, and Cys synthesis de novo as well are quantified using their plasma kinetics data. Wool growth rate is predicted from the amount of the amino acid available for protein retention and the partition ratio to wool growth. The estimated requirements for Met and Cys absorption for Merino sheep at maintenance are 0·45 to 0·75 g/day and 0·52 to 0·63 g/day depending on the live weight of the sheep. When wool growth rate increases to 10 g/day, the requirements increase to 0·91 to 1·24 g/day and 1·97 to 2·02 g/day respectively. The utilization efficiency for protein retention varies with the level of absorption, and is 0·02 to 0·55 for Met, and 0·09 to 0·55 for Cys. The model shows that wool growth rate is restricted by the lack of Cys supplied in conventional diets and is very sensitive to changes in oxidation of the amino acids.
Feeding behaviour, food intake and milk production responses of lactating dairy cows to diets based on grass silage of high or low dry-matter content, supplemented with quickly and slowly fermentable energy sources
Authors: Romney D. L. , Blunn V. , Sanderson R. , Leaver J. D.
Published: August 2016

Twelve dairy cows in early lactation were offered low (L; 215 g/kg) or high (H; 449 g/kg) dry matter(DM) content silages, prepared using material from the same sward. In addition, all animals received 9 kg/day, of supplements based on barley (B), sugar-beet pulp (SB) or a 50: 50 mixture of the two (B: SB), in two equal portions at 07:30 and 14:30 h. The six treatments were offered in an incomplete Latin square design. Mean intakes of H (14·4 kg DM per day) were significantly higher than intakes observed for L (10·0 kg DM per day) (P < 0·001). Within silage type, highest intakes were observed for cows receiving the SB supplement (P < 0·01). Higher intakes of H were reflected in higher total milk yield (P < 0·05) as well as fat (P < 0·05) and protein (P < 0·01) yield. Milk protein concentration was greater for animals receiving silage H (P < 0·001), with lower values being observed for animals consuming SB (P < 0·05), within silage type. Time spent eating, duration and number of meals were similar for either silage and the higher intakes of H silage reflected greater intake rates (g DM per min) (P < 0·001) resulting in larger meal sizes (P < 0·001). All chewing indices (time spent eating silage, ruminating and total time chewing per kg DM ingested) were greater for the L silage (P < 0·001). It is concluded that the benefits in forage intake with higher DM grass silages, for high yielding dairy cows, are associated with consequential benefits in milk yield and milk protein content. The most likely explanation for the greater intakes is a faster particle breakdown in the rumen allowing larger meal sizes before animals became constrained. The higher intakes of silage when animals consumed the SB supplement may be due to a slower rate of fermentation of the supplement, which was more closely matched to that of silage. Although not significant there was a tendency for differences in silage intake between animals receiving B compared with SB supplements to be greater for animals receiving the H silage suggesting that supplementation strategies to ensure optimal forage utilization may differ for silages of differing DM content.
Estimates of parental-dominance and full-sib permanent environment variances in laying hens
Authors: Misztal I. , Besbes B.
Published: August 2016

Estimates of variance components for five egg traits on 26265 laying hens were obtained by restricted maximum likelihood (REML) using several models. In the DOMFS model, the effects included hatch group, additive genetic, full-sib, parental dominance and inbreeding depression. In the DOM model, the full-sib effect was eliminated. In the FS model, the parental dominance effect was eliminated. In the ADD model, both the full-sib and the dominance effects were eliminated. In the DOMFS model, the estimates of the full-sib variance were generally higher for egg production traits and lower for egg characteristics than those of the parental dominance variance. However, this model has partially failed in separating these two components. When the full-sib effect was removed from the model, almost all of its estimated variance moved to the estimated parental dominance variance. When the parental dominance effect was removed from the model, almost all of its estimated variance moved to the estimated full-sib variance. The estimates obtained with REML and the DOM model were compared with those obtained by method R and tilde-hat methodologies. The d2 (ratio of dominance variance to total variance) differed by up to 86% for method R and up to 225% for tilde-hat. The h2 differed by up to 26 and 28%, respectively. For data sets that are too large to be analysed with REML, method R is a feasible alternative. A model for estimation of dominance variance should also include the full-sib or a similar effect, provided the data set is large. Similarly, to analyse egg production traits, the model should include at least the full-sib effect.
Analysis of censored survival data using random regression models
Authors: Veerkamp R. F. , Brotherstone S. , Engel B. , Meuwissen T. H. E.
Published: August 2016

Censoring of records is a problem in the prediction of breeding values for longevity, because breeding values are required before actual lifespan is known. In this study we investigated the use of random regression models to analyse survival data, because this method combines some of the advantages of a multitrait approach and the more sophisticated proportional hazards models. A model was derived for the binary representation of survival data and links with proportional hazards models and generalized linear models are shown. Variance components and breeding values were predicted using a linear approximation, including time-dependent fixed effects and random regression coefficients. Production records in lactations 1 to 5 were available on 24741 cows in the UK, all having had the opportunity to survive five lactations. The random regression model contained a linear regression on milk yield within herd (no. = 1417) by lactation number (no. = 4), Holstein percentage and year-month of calving effect (no. = 72). The additive animal genetic effects were modelled using orthogonal polynomials of order 1 to 4 with random coefficients and the error terms were fitted for each lactation separately, either correlated or not. Variance components from the full (i.e. uncensored) data set, were used to predict breeding values for survival in each lactation from both uncensored and randomly censored data. In the uncensored data, estimates of heritabilities for culling probability in each lactation ranged from 0·02 to 0·04. Breeding values for lifespan (calculated from the survival breeding values) had a range of 2·4 to 3·6 lactations and a standard deviation of 0·25. Correlations between predicted breeding values for 129 bulls, each with more than 30 daughters, from the various data sets ranged from 0·81 to 0·99 and were insensitive to the model used. It is concluded that random regression analysis models used for test-day records analysis of milk yield, might also be of use in the analysis of censored survival data.