bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of carboxylic salts on silage conservation, and voluntary intake and growth of steers given lucerne silage
Authors: Charmley E. , McQueen R. E. , Veira D. M.
Published: August 2016

Three wilted silages (dry matter concentration of approximately 300 g/kg) were prepared from early-bloom lucerne which received no additive (MG-0), or was treated with a mixture of carboxylic salts (Maxgrass) at either 4 (MG-4) or 8 (MG-8) l/t fresh crop. Silages were stored in tower silos. Resulting silages were offeredad libitumto growing Holstein steers without supplementation. Untreated silage (MG-0) exhibited an extensive, predominantly lactic acid fermentation. The nitrogen (N) fraction was highly soluble, relative to the crop at ensiling. Silage fermentation and protein solublization were restricted by Maxgrass application. Maxgrass application reduced aerobic stability of silage removed from the upper third of silos but not of silage from the lower portion of silos. Apparent digestibility showed a quadratic response to level of Maxgrass application (P< 0·05). Voluntary intake was not affected by Maxgrass addition (P> 0·005) but intake of all silages was high (30 g/kg live weight (LW)). There was a positive linear response (P< 0·05) in LW gain to Maxgrass application with gains of 0·74, 0·86 and 0·87 kg/day being achieved in steers given MG-0, MG-4 and MG-8 silages, respectively. Degradability of silage N determined in nylon bags in situ was unaffected by Maxgrass application. However, the immediately degradable N fraction was reduced by Maxgrass application (linear effect,P< 0·001; quadratic effect,P< 0·05). Benefits in animal performance due to Maxgrass application were attributed to improved N composition while restricted carbohydrate fermentation during ensiling was considered to be of secondary importance.
Growth and body condition of sows given different feeding regimes during the rearing stage and through eight parities when housed in groups with straw bedding
Authors: Simmins P. H. , Edwards S. A. , Spechter H. H.
Published: August 2016

A 2 X 3 factorial experiment was designed to study the consequences of feeding strategy during rearing and pregnancy over eight parities on sow growth and body condition. Two hundred and fifty-four gilts were group-fed on a restricted scale rising to either 2·25 (L) or 2·70 (H) kg/day (12·5 MJ/kg digestible energy (DE), 193 g/kg crude protein (CP) diet) from 70 to 175 days of age. A total of 156 of the L and H gilts were then given either 1·8 (l), 2·1 (m) or 2·4 (h) kg/day during subsequent pregnancies (12·9 MJ/kg DE; 177 g/kg CP diet). The same diet was offered to a standard scale during lactation. Sows were group-housed in pregnancy and given straw bedding. Losses of sows in rearing and each parity were not associated with treatment. After rearing, data have been presented only for those sows which completed eight parities. At 175 days of age, H gilts had grown faster (P < 0·001). From 175 days to service all gilts were given the same feeding regime but L gilts put on significantly more weight than H gilts, exhibiting more efficient utilization of food. There were no statistically significant differences in weights between L and H sows after the third pregnancy but L sows gained more weight than H sows in most pregnancies. The sows grew in each parity, indicating mature body size was not achieved. The pregnancy regimes had a significant (P < 0·05) effect on live weight, P2 backfat measurement, body length, neck circumference and condition score. Pregnancy treatment h produced the heavier and fatter animals but not all treatment l sows maintained adequate backfat levels for six parities. When housed in groups and given a generous supply of straw, the nutritional requirements of sows to sustain growth and body condition suitable for a long life may be less than has been previously identified for sows housed on concrete and slats without bedding.
Reproductive performance of F1 crossbred dairy cows used for draught: effect of work and diet supplementation
Authors: Zerbini E. , Gemeda T. , Franceschini R. , Sherington J. , Wold A. G.
Published: August 2016

Forty pregnant F1crossbred cows (20 Holstein-Friesian × Boran and 20 Simmental × Boran) were assigned to a 2 × 2 (work × diet) factorial experiment as follows: supplemented-non-working (SNW), supplemented-working (SW), non-supplemented-non-working (NSNW) and non-supplemented-working (NSW). Working cows pulled sledges 100 days/year (pull = 350 to 450 N, 4 h/day, 4 days/week). Conception and oestrus at fixed times (200 and 365 dayspost partum) were analysed using linear logistic models. Proportional hazard models were used for analysing ‘failure’ time data such as time to first oestrus or time to conception. Diet supplementation significantly decreased days to first oestrus and days to conception in non-working and working cows. SW cows had similar reproductive performance to NSNW cows. In supplemented cows, work significantly delayed days to conception. However, by 365 dayspost partum, conception rate was similar for SNW and SW cows. Body condition at calving significantly affected post-partum reproductive ability of non-working and working cows. Natural grass hay alone could not support potential reproductive ability of crossbred cows. Work output of supplemented cows may be associated with longer calving intervals. The economic trade-offs between longer calving intervals and work output should be examined in detail.
The degradation of oilseed cakes and their effects on the intake and rumen degradability of maize stover given to Ethiopian Menz sheep
Authors: Sibanda S. , Osuji P.O. , Nsahlai I. V.
Published: August 2016

Six rumen cannulated sheep (26·1 (s.d. 2·24) kg live weight) given maize stoverad libitumwere supplemented with either sunflower (Helianthus annus) cake (SFC), decorticated cottonseed (CSC) or noug (Guizotia abyssinica) cakes (NGC) with or without crushed maize grain. The 6×6 Latin-square experiment studied the degradation properties of the oilseed cakes and their effects and that of maize on the degradation of maize, maize stover and the composite diet.

Seedcakes differed in the degradability characteristics of dry matter and nitrogen: intercept (a) (P< 0·001); potentially degradable fraction (b) (P< 0·001); rate of degradation (c) (P< 0·001); and the effective degradability (P< 0·0001). The pooled sum of the degradabilities of the individual ingredients were significantly lower than that of mixed ingredients (composite diet) (P< 0·001).

The main effects of protein and maize were not significant on the degradation of maize stover. Maize had the tendency to depress the rates of degradation of stover by 0·52 with SFC.

Although the protein × maize interaction was not significant on maize stover degradability, it is important to note that maize had the effect of increasing stover degradation rate with CSC and NGC, but a depressing effect with SFC. Hence it was concluded that the carbohydrate effect on roughage degradation rate may vary as a function of the difference between the degradation rate of the energy and protein supplements.
The effects of food level during lactation and early gestation on the reproductive performance of mature sows
Authors: Hughes P. E.
Published: August 2016

Seventy-six Large White × Landrace sows from parities 2 to 6 were allocated to one of four treatments at day 110 of gestation on a parity and live-weight basis. The four treatments involved food levels of either 3 or 6 kg/day during a 28-day lactation followed by either 1·75 or 3·50 kg/day during the first 28 days of gestation. Litter size suckled was standardized at 10 piglets wherever possible. Live weight and backfat changes were monitored in all sows and litter growth and survival rates were recorded. Post weaning all sows were given daily boar contact and mated twice at the first observed oestrus. A single blood sample was collected from each sow at days 7, 14, 21 and 28 of gestation for determination of plasma progesterone concentration. Data on litter size and piglet birth weights were collected at the subsequent parturition. Sows low-fed during lactation lost significantly more live weight (31·2v.5·8 kg,P< 0·01) and P2 backfat (3·6v.1·9 mm,P< 0·05) in lactation than did high-fed sows. Underfeeding the lactating sow also significantly reduced the weaning weight of the litter (62·3v.68·7 kg for low-v.high-fed sows,P< 0·05), but did not significantly change either creep food intake by the litter or pre-weaning mortality rate. Parity 2 sows weaned significantly heavier piglets and litters than did sows from parities 3 to 6 (7·48 and 74·9 kgv.6·72 and 63·8 kg respectively,P< 0·01). Food level in lactation did not significantly influence the length of the rebreeding interval (6·3v.7·3 days for high-v.low-fed sows) and although there was a two-fold difference in the proportion of sows failing to exhibit oestrus post weaning (0·08v.0·16 for high-v.low-fed sows) this difference was also not significant. Lactation food level did not significantly influence either sow live-weight or backfat change in gestation, plasma progesterone concentrations during early gestation or subsequent litter size. However, sows low-fed in lactation did tend to produce fewer piglets in the subsequent litter (9·54v.10·75 piglets born alive for low- and high-fed sows respectively,P= 0·062). Post-weaning reproductive performance was significantly affected by sow live weight (P< 0·05) and backfat (P< 0·01) at parturition, and live weight (P< 0·01) and backfat (P< 0·05) at weaning, but not by changes in these parameters during lactation. Food level in early gestation did not significantly influence either plasma progesterone concentrations, the size of the subsequent litter (10·09v.20·29 piglets born alive for high- and low-fed sows respectively) or mean piglet birth weight (1·27v.2·22 kg for high- and low-fed sows respectively). It is concluded that (1) both lactation food level and parity may alter pre-weaning piglet growth, and (2) the effects of lactation food level on the subsequent reproductive performance of mature sows appear to be different from those seen in parity 1 sows.
Growth, abdominal fat content, heat production and plasma hormone levels of naked-neck and control broiler chickens
Authors: Decuypere E. , Buyse J. , Mérat P. , Zoons J. , Vloeberghs J.
Published: August 2016

The depressing effect of high rearing temperature (30°C) on body weights of heterozygous naked-neck broiler chickens was apparently less pronounced than in control broiler chickens but no effect of genotype, rearing temperature or interaction on abdominal fat pad content was found. Both genotype and rearing temperature affected plasma tri-iodothyronine but not growth hormone or insulin-like growth factor 1 levels in plasma. Rearing temperature of 20°C or 30°C had effect neither on the slope of the thermoregulatory heat production curves nor on the lower critical temperature in either genotypes except at 4 weeks of age.
A note on the effect of sustained exercise on straw intake and body weight in lactating cattle
Authors: Matthewman R. W. , Oldham J. D. , Horgan G. W.
Published: August 2016

The effect of exercise (walking 10.6 km/day and climbing 480 m/day) on intake of barley straw and body weight changes in 12 pregnant lactating suckler cows was investigated. Three groups of four cows receivedad libitumbarley straw and 4 kg per cow per day of different supplements. Neither exercise nor supplement had a significant effect on straw intake. Cows gained weight when not exercised, but lost weight during the exercise period. The experiment confirms previous findings that animals performing moderate work and given poor quality roughage, in the short term cannot increase daily intake to meet energy requirements and that intake may decrease when animals work.
Field data analysis of cytoplasmic inheritance of dairy and fitness-related traits in cattle
Authors: Schnitzenlehner S. , Essl A.
Published: August 2016

Field data of the Austrian Simmental population were analysed using restricted maximum likelihood (REML) with an animal model where additive direct, additive maternal and cytoplasmic effects were treated as random and the effect of the year of first calving as fixed. Traits analysed were milk yield, fat and protein content, persistency, days open and herd life. All dairy traits were pre-adjusted for best linear unbiased prediction (BLUP) herd-year effects, milk yield additionally for season, age at first calving and days open. After applying specific data restrictions, the number of records for the various traits ranged from 3360 to 51889. Identification of cow lineages was based on pedigree information from the official milk recording scheme, with a span of at least four and up to 16 generations. The number of lineages per trait varied and ranged from 484 to 3195, with an average size of 15 members (for herd life 7). Evaluations of the relevant variance components for the dairy and fitness-related traits investigated were separate for the first three lactations.

The estimated variance components for cytoplasmic effects were close to zero for all dairy traits with the exception of first lactation milk yield, where a significant value of 2.0% of the total phenotypic variance was found. Significant contributions of cytoplasmic lineages to total variance in all lactations, however, were estimated for persistency (2·6 to 3.8%), days open (1·8 to 2.9%) and for both true and functional herd life (4.6% each). The portions of additive maternal variance and covariance between additive direct and additive maternal effects on total variance were very close to zero for all traits investigated. The maximum differences between BLUP lineage effects were 373 kg for first lactation milk yield, 44 days for days open (first lactation), 1·6 and 2·8 years for true and functional herd life and, on average, 1·0 kg for standard deviation of test day milk yields (persistency) of the first three lactations.

Removing the cytoplasmic effect from the model led to increased estimates of the additive direct heritability. Further model aspects such as interaction between additive and cytoplasmic gene effects and possible confounding between cytoplasmic and herd effects are discussed.
Follicular dynamics during the oestrous cycle in dairy goats
Authors: Gonzalez de Bulnes A. , Santiago Moreno J. , Gomez-Brunet A. , Inskeep E. K. , Townsend E. C. , Lopez-Sebastian A.
Published: August 2016

Development of all follicles with antral diameter ≥2 mm during the oestrous cycle was characterized in goats of the Murciana-Granadina dairy breed by daily transrectal ultrasonography. Of nine does initially synchronized in oestrus, six returned to oestrus and three did not. In the first six does, mean cycle length was 21·2 (s.e. 2-3) days. There were mean total numbers of 6·2 (s.e. 0·6) small (2 to 3 mm), 1·9 (s.e. 0·3) medium (4 to 5 mm), and 1·0 (s.e. 0·2) large follicles (≥6 mm) each day but only numbers of large follicles differed with day of cycle (P < 0·01). The diameters of the largest follicle (LF1), the second largest (LF2) and the remaining follicles (RF) varied with day of cycle (P < 0·01). The LF1 and LF2 varied with day in similar patterns but the difference in diameter between them (P < 0·05) was greatest on days 7 and 9 (2·3 mm) and days 19 to 23 (2·2 to 3·8 mm), and least on days 2, 15, 16 and 18 (0·5 to 0·8 mm). The relationship between the LF1 and LF2 to the RF differed only early or late in the cycle when concentrations of progesterone were low (P < 0.05). There was some evidence to support follicular growth in waves. Although the number of apparently new follicles detected (4·8 (s.e. 0·4) per day) did not vary with day of cycle, follicles emerging at 3 mm over a 48-h period that grew to a diameter of ≥6 mm were distributed non-randomly in three of six cyclic does. The three cystic does that did not return to oestrus by day 25 had large follicles (16 to 28 mm), fewer new follicles (3·3 (s.e. 1-1) per day; P < 0·01) than cyclic does (4·8 (s.e. 0·4) per day) and fewer follicles that became largest (4·0 v. 8·8 in cyclic does; P < 0·01).
On the variation of urinary excretion of creatinine and purine derivatives in pregnant and lactating ewes given diets with different protein contents
Authors: Dapoza C. , Castrillo C. , Balcells J. , Martín-Orúe S. , Guada J. A.
Published: August 2016

The effect of the physiological state and dietary protein level on urinary excretion of creatinine (C) and purine derivatives (PD) was studied in two experiments carried out with pregnant and lactating ewes to evaluate whether the PD/C ratio in urine can he confidently used as an index of PD excretion. In both experiments ewes were given ammonia-treated straw and concentrates including different levels of fish meal and the excretion in urine and milk and the plasma concentration of C, allantoin (AL), xanthine, hypoxanthine and uric acid was measured.

Creatinine excretion (in urine and milk) was higher in pregnant ewes than in those lactating (492 and 420 (s.e. 10.0) μmol/kg maternal live weight0.75) and no significant differences were found due to number of foetuses and dietary protein level. The coefficient of variation was 0·10 in both pregnancy and lactation and individual variation accounted for proportionately 0·78 and 0·93 of total variation. The AL/C ratio in urine was highly correlated with daily AL excretion (r = 0·90 and 0·78 in pregnant and lactating ewes, respectively). Changes in PD excretion with experimental treatments were mainly reflected in AL, as the main component (0-83) of total PD. Most of the variation in AL excretion was explained by differences in rumen fermentable organic matter intake (RFOMI) (R2 = 0·79) and AL excretion did not differ between treatments when expressed per kg of RFOMI. In contrast to this the ratio AL/digestible organic matter intake decreased with increasing levels of fish meal in the diet. Urinary PD excretion was better related to estimated PD kidney tubular load (r = 0·76) than to PD plasma concentration (r = 0·64).

The results suggest that creatinine excretion is scarcely affected by the number of foetuses in pregnancy and dietary protein level but if the AL/С in urine is used instead of total collection as an index of purines absorbed in the duodenum, differences in urinary creatinine excretion due to physiological state must be accounted for.
The effects of group size on the ingestive and social behaviour of grazing dairy cows
Authors: Rind M. I. , Phillips C.J. C.
Published: August 2016

An experiment was conducted with 48 dairy cows grazed in treatment groups of four, eight or 16 cows per group, whose grazing, social and resting behaviour was recorded over a 53-day period. Cows in groups of four stayed closer to their nearest neighbour, moved their head more rapidly from side to side during grazing and spent more time ruminating than cows in larger groups, suggesting that they were more vigilant against a perceived prédation risk. Cows in the group of 16 were more aggressive, maintained a greater distance to their nearest neighbour and had a faster rate of stepping while they grazed, compared with cows in smaller groups, suggesting increased inter-cow competition. They also spent longer grooming themselves, which normally acts as a displacement activity and may indicate increased stress. Cows in groups of eight had a faster biting rate when grazing than cows in small or large groups and they spent the longest time lying down. There were no effects of group size on milk production but across treatment groups the high yielding cows were the first to initiate grazing and to enter the milking parlour.
Lactation performance of purebred Arsi cows and Friesian × Arsi crosses under pre-partum and post-partum supplementary feeding regimes
Authors: Kurtut M. Y. , Tawah C. L. , Rege J. E. O. , Nega-Alemayehu  , Mesfin-Shibre
Published: August 2016

A study was conducted at the Asella Station in the Arsi Region of Ethiopia to investigate the dairy performance of indigenous purebred Arsi and Friesian × Arsi crosses under different pre-partum and post-partum supplementary feeding regimes. A total of’343 first-lactation animals were involved in the experiment. Lactation performance was not significantly affected by pre-partum supplementation. Post-partum supplementary feeding significantly affected total lactation milk and butterfat yields of the crosses but not the purebred Arsi. Arsi crosses produced more milk (1873 (s.e. 65·1) v. 258 (s.e. 31·7) kg) and butterfat (92 (s.e. 4·0) v. 25 (s.e. 2·8) kg) than purebred Arsi. The crosses stayed in lactation longer (474 (s.e. 13·0) v. 179 (s.e. 15·4) days) than the latter. Purebred Arsi manifested much more variation in total lactation milk yield (CV: 1·27 v. 0·37), lactation length (0·91 v. 0·30) and butterfat yield (0·71 v. 0·42) than Arsi crosses. F1 crosses produced slightly more milk (+266 kg) and butterfat (+19·3 kg) but had shorter (-30 days) lactations than the backerosses.
Simulation of growth in pigs: evaluation of a model to relate thermorégulation to body protein and lipid content and deposition
Authors: Knap P.W.
Published: August 2016

A dynamic model for simulation of growth in pigs was extended by a module to assess maximum and minimum heat loss (HLcold, HLhot) for a given pig, to compare these figures to heat production (HP), and to take thermoregulatory action when HP< HLcold(cold conditions) or HP> HLhot(hot conditions).

HLcoldand HLhotwere largely determined according to algorithms obtained from the literature, hut HLcold was made dependent on body fat depth through tissue insulation. Data to establish the relation (Ύ = 0.05 + 0.002 x X) between cold tissue insulation (Ύ in °C.m2per W) and backfat depth (X in mm) independent of body weight were obtained from the literature. The same data showed that HLhotis not related to backfat depth in pigs.

Cold thermoregulatory action included an increase of ad libitum food intake. Hot thermoregulatory action included reduction of physical activity, increase of body temperature, wetting of a proportion of the skin and reduction of dia libitum food intake.

A sensitivity analysis showed that the model’s output in terms of ãd libitum food intake, HP, protein deposition (Pdep) and lipid deposition (Ldep) is strongly sensitive to the characterization of the genotype being simulated. The model was used to simulate trials from the literature. Although the model does not explicitly calculate lower and upper critical temperatures, these could be adequately predicted from its output. Comparison of model output with experimental data revealed an adequate prediction of ad libitum food intake and of the partitioning of ad libitum ingested metabolizable energy (ME) into HP, Pdepand Ldepin cold, thermoneutral and hot conditions. At restricted ME intake, and especially in cold conditions, the model tends to overestimate HP and underestimate Ldep, probably because it does not take account of long-term acclimatization.
The relationship between placental and piglet birth weights and growth traits
Authors: Biensen N. J. , Haussmann M. F. , Lay D. C. , Christian L. L. , Ford S. P.
Published: August 2016

Our laboratory recently reported that the ratio of a piglet’s weight to that of its placenta (RATIO) varies approximately three-fold within a litter, due predominantly to variation in placental size which is known to be a limiting factor in litter size. It was further determined that selection of boars and gilts with a higher than average RATIO for breeding resulted in an increased litter size and reduced placental weights. The objective of this experiment was to examine the effects of RATIO on economically important production traits (piglet survival to weaning, 21-day weights, days to 105 kg, backfat depth and loin muscle area at 105 kg) in a purebred breeding stock herd of Finnish Yorkshire and Landrace pigs. Sows were monitored throughout farrowing and each piglet was matched to its placenta. Each piglet and its placenta were individually weighed and a RATIO determined. Placental weight but not piglet birth weight exhibited a strong (P < 0·001) negative correlation with RATIO (r = -073). Up to three-fold differences in RATIO were observed within a single litter. These differences were much greater than the variation noted between litters and litter mean RATIO was not significantly associated with litter size. The distribution of individual piglet RATIOS across the entire group of pigs ranged from 2·8 to 11·4 suggesting a marked difference in placental efficiencies. No significant association was seen between RATIO and 21-day weight, days to 105 kg, backfat depth or loin muscle area. Thus, an above average ratio of a piglet’s weight to that of its placenta is indicative of a smaller more efficient placenta and appears to have no subsequent detrimental effects on growth efficiency.
Glucose challenge in early lactating dairy cows selected for high or low milk-fat concentration
Authors: Åkerlind M. , Emanuelson M. , Dahlborn K. , Holtenius K.
Published: August 2016

Responses to intravenous glucose challenge (no. = 26) and basal metabolite and hormone concentrations (no. = 68) were determined in dairy cows selected for high (HFI) or low (LFI) milk-fat concentration but with similar 40 g/kg fat-corrected milk (FCM) yields. All cows were given a mixed diet ad libitum. Following a glucose challenge the insulin release was higher (P < 0·05) and the glucose clearance rate faster (P < 0·05) in the HFI cows compared with the LFI cows. Basal plasma concentrations of the metabolites alanine, β -hydroxybutyrate, glucose, non-esterified fatty acids and urea and the hormones insulin-like growth factor-1 (IGF-1), insulin and leptin were not influenced by selection line.
Sodium chloride supplements increase the salt appetite and reduce stereotypies in confined cattle
Authors: Phillips C. J. C. , Youssef M. Y. I. , Chiy P. C. , Arney D. R.
Published: August 2016

The influence of prior exposure to high salt diets on the salt appetite and the exhibition of stereotyped behaviour patterns was investigated with individually penned calves and tethered dairy cows. In the first experiment one half of a group of 12 calves received concentrates with the sodium content increased from 4 to 9 g/kg by the addition of NaCl up to weaning at 6 weeks, the other half had no supplementary NaCl added to the concentrates. Adding the NaCl increased the food intake of the calves, the time spent ruminating and live weight. Stereotyped behaviour patterns, such as self-grooming, licking the pen or buckets and ear sucking were reduced by adding NaCl. Calves were tested for their salt preference at 6 months of age by adding varying quantities of NaCl to silage. Exposing calves to supplementary NaCl in the concentrate pre-weaning increased the preferred sodium concentration of silage from 3 to 9 g/kg dry matter (DM). In the second experiment 36 tethered dairy cows received either a restricted concentrate and forage diet with a mean dietary sodium concentration of 2 g/kg DM, or the same diet but with the sodium content increased to either 7 or 12 g/kg DM by adding NaCl to the concentrates. There was no effect of NaCl on feeding or ruminating behaviour but the total amount of stereotyped behaviour, including mouthing or rubbing the tethering chain or bars, self-grooming and nosing or pawing the ground, decreased with increasing salt in the diet. It is concluded that increasing the sodium content of the diet of young calves from 4 to 9 g/kg increased their subsequent salt appetite and that increasing the salt content of the diet of calves or cows in restricted housing conditions can reduce the amount of stereotyped oral behaviour.
In situ rumen degradation of dry matter and crude protein in ewes and dairy cows
Authors: Šebek L. B. J. , Evererts H.
Published: August 2016

Comparative studies were performed on the in-situ rumen degradation rate (kd) and the in-situ rumen undegradable residue (U) of dry matter (DM) and crude protein (CP) in sheep and dairy cows. The effect of different treatmentsfor sheep were investigated together with the validity of using cow-based reference protein values of foods for sheep. The effect of different breeds (Texel ewes and crossbred ewes), dietary roughage: concentrate ratio and shearing (mild cold exposure) were investigated for sheep.

The in-situ rumen incubations were performed in accordance with standard operational procedures which were comparable for both species. The foods under consideration were hay and concentrates. Cows displayed lower (DM 0·53 , CP 0·86) Kds than sheep for concentrates.

For hay a clear trend between cows and sheep was not observed but cows displayed 0·40 lower Kds than Texel ewes and 0·30 higher Kds than crossbred ewes. For concentrates U levels did not differ between species but for hay cows had 0·45 higher U values than Texel ewes. Texel ewes showed 0·45 higher Kd and 0·35 lower U for DM and CP than crossbred ewes. Dietary roughage: concentrate ratio in sheep diets did not influence the Kds and Us of the foods under consideration. Shearing of crossbred ewes increased Kd of CP by 0·25 and reduced U for DM and CP by 0·20 and 0.24 .

In conclusion different in situ rumen degradation rates were found between dairy cows and sheep. This probably makes using reference protein values of foods invalid for sheep since they are based on data for cows. Differences (Kd andU) were also found between sheep breeds and between unshorn and shorn crossbred ewes (mild cold exposure). No effect on rumen degradation kinetics could be attributed to dietary roughage: concentrate ratio.
Influence of milking and restricted suckling regimes on milk production and calf growth in temperate and tropical environments
Authors: Sandoval-Castro C.A. , Anderson S. , Leaver J.D.
Published: August 2016

Two experiments were carried out to investigate the effect of restricted suckling and milking regimes on milk yield, milk composition and calf growth. Experiment 1 was carried out in temperate conditions in the United Kingdom and experiment 2 under tropical conditions in Mexico. In experiment 1 a Latin rectangle (change-over) design with 3-week periods was used with eight Holstein Friesian cows suckling their Simmental-sired calves. Saleable milk yield (SMY), sucked milk (CSM), milk composition and calf performance were studied. The treatments were: once a day milking (a.m.) with suckling immediately after (1χAM); once a day milking (a.m.) with suckling p.m. (1χPM); twice daily milking with suckling after a.m. milking (2χAM); twice daily milking with suckling after each milking (2χ2χ). The cows were offered maize silage ad libitum and 4·3 kg dry matter (DM) per day of rapeseed meal plus minerals and vitamins. The calves had ad libitum access to concentrates (165 g crude protein (CP) per kg DM) and wheat straw. In experiment 2, 11 B. indicus χ B. taurus cows, suckling their Brahman-sired calves were used in an experiment with the same treatments and experimental design. Cows were offered star grass (Cynodon nlemfuensis) hay ad libitum and 4.0 kg DM per day of concentrate (117 g CP per kg DM). The calves had ad libitum access to concentrate (151 g CP/kg DM), star grass hay and Ramon leaves. For 1χAM, 1χPM, 2χAM and 2χ2χ respectively in experiment 1, the total milk yields (TMY = SMY + CSM) were 17.9, 18.0, 16.7 and 19.5 kg/day (s.e.d. 1.11) and SMY represented 0.70, 0.45, 0.77 and 0.53 of TMY. Corresponding results for experiment 2 were 6.0, 6.2, 7.0 and 7.1 kg/day (s.e.d. 0.32) and 0.69, 0.45, 0.78 and 0.61. Effects of treatment on milk yield and composition were consistent with the feedback inhibitor of lactation theory. It was concluded that different milking and restricted suckling patterns can be used to manipulate saleable milk production and calf growth. Holstein Friesian dairy cattle in a restricted suckling system without the calf presence at milking, behaved similarly to zebu-crossbred cows by reducing milk let down at milking.
Genetic resistance to gastro-intestinal nematode parasites in Red Maasai, Dorper and Red Maasai X Dorper ewes in the sub-humid tropics
Authors: Baker R.L. , Mwamachi D.M. , Audho J.O. , Aduda E.O. , Thorpe W.
Published: August 2016

Resistance to naturally acquired gastro-intestinal (GI) nematode parasite infections (predominantly Haemonchus contortus) was studied in 166 Red Maasai, 230 Dorper and 294 crossbred (Red Maasai Х Dorper) ewes in the sub-humid coastal region of Kenya. Live weights (LWT), blood packed-cell volume (PCV) and faecal egg counts (PEC) were recorded at mating, 3 months post mating, 1 week before lambing and 1, 2 and 3 months post lambing for four separate lambings that took place between 1993 and 1996. The Red Maasai ewes were more resistant to GI nematode infections than Dorper ewes as shown by their significantly lower FEC and significantly higher PCV at most of the sampling times over the reproductive cycle. The breed difference for FEC was significant in the lactating ewes but not in the non-lactating ewes. At most sampling times, the crossbred ewes were as susceptible as the Dorper ewes in terms of both PCV and FEC, particularly at the 1 and 2 month post-lambing samplings. Resistance was also manifested by a lower proportion of ewes having to be treated with an anthelmintic and a lower mortality rate in the Red Maasai than the Dorper. The Red Maasai ewes were significantly lighter by about 1 to 2 kg than the Dorper ewes at all sampling times. There was a significant increase in FEC and decrease in PCV over the first 2 months of lactation in lactating ewes compared with non-lactating ewes. This peri-parturient increase in FEC occurred in both breeds and the crossbreds but was more marked in the susceptible Dorper ewes.
An evaluation of the success of MOET in two breeds of hill sheep maintained under normal systems of hill flock management
Authors: Bari F. , Khalid M. , Haresign W. , Merrell B. , Murray A. , Richards R.I.W.
Published: August 2016

This study was undertaken to investigate factors affecting the success of multiple ovulation and embryo transfer (MOET) in Scottish Blackface (no. = 120) and Welsh Mountain (no. = 120) ewes, over a period of 2 years using a laparoscopic procedure for both embryo recovery and transfer. Superovulation was induced with ovine FSH, with 98 to 100% of ewes of both the breeds responding to the treatment. The overall mean superovulatory responses were 15⋅0 (s.e. 0⋅8) and 12⋅5 (s.e. 0⋅7) for Scottish Blackface and 15⋅3 (s.e. 0⋅9) and 12·8 (s.e. 0⋅8) for Welsh Mountain ewes in years 1 and 2, respectively. However, there was a wide degree of variation in superovulatory responses within each breed, with a range of 3 to 29 in Scottish Blackface and 1 to 40 in Welsh Mountain ewes. The mean embryo recovery rate was 71⋅9 (s.e. 3⋅5) % and 69⋅6 (s.e. 3⋅4) % for Scottish Blackface and 57⋅5 (s.e. 4⋅1) % and 60⋅6 (s.e. 3⋅6) % for Welsh Mountain ewes in years 1 and 2, respectively. The mean number of embryos recovered from Welsh Mountain ewes was significantly (P < 0⋅05) lower than that from Scottish Blackface ewes in both years. The lower mean number of embryos recovered in year 2 for both breeds was entirely a reflexion of the lower superovulatory responses in year 2. A significant (P < 0⋅001) relationship was observed between superovulatory response and the number of embryos recovered for both breeds. Some 77% and 72% of Scottish Blackface ewes and 65% and 73% of Welsh Mountain ewes yielded four or more transferable embryos in years 1 and 2, respectively. Neither the mean number nor the mean percentage of transferable embryos per donor ewe differed between breeds or years. A significant (P < 0⋅001) negative relationship was observed between the time of onset of oestrus and both superovulatory response and number of embryos recovered in Scottish Blackface ewes only. Embryo quality was affected by the time of onset of oestrus. In both breeds, the highest proportion of grade 1+2 embryos and the lowest proportion of unfertilized/degenerate embryos occurred in the middle range time, with a reduction in the proportion of grade 1+2 embryos in ewes that came into oestrus either early <19 h) or late (>30 h) after sponge removal. Only one embryo was transferred to each recipient and the embryo survival rates were 76⋅8% and 74⋅6% (Scottish Blackface), and 69⋅6% and 87⋅3% (Welsh Mountain) for years 1 and 2, respectively. Overall the results of this study suggest that MOET is as successful in hill ewes as has been reported for lowland breeds, even without making any major concessions to their hill status.
Association between non-parturient post-partum hypocalcaemia and the interval from calving to first ovulation in Holstein-Friesian cows
Authors: Jonsson N.N. , Pepper P.M. , Daniel R.C.W. , McGowan M.C. , Fulkerson W.
Published: August 2016

This study was undertaken to quantify the effect of episodes of subclinical hypocalcaemia on the interval from calving to first ovulation. It incorporated three separate surveys during early lactation of 44 and 60 cows at Mutdapilly Research Station and 56 cows at Wollongbar Agricultural Institute. Twenty-five, 37 and 39% of cows respectively, experienced episodes later than 3 days after calving, of non-parturient post-partum hypocalcaemia, when plasma calcium concentration fell below 2⋅00 mmolll. Episodes of subclinical hypocalcaemia did not affect the interval to first post-partum ovulation in the two experiments conducted at Mutdapilly Research Station but ovulation was significantly delayed in cows that experienced episodes of subclinical hypocalcaemia at Wollongbar Agricultural Institute.
Effect of concentrate feeding on milk yield and body-weight change of Awassi ewes and the growth of their lambs
Authors: Al Jassim R.A.M. , Aziz D.I. , Zorah K. , Black J.L.
Published: August 2016

The response of Awassi ewes to graded amounts of supplementary concentrate diet was examined for the first 12 weeks of lactation. The growth rate of lambs and their health status were also investigated. Seventy-five ewes were divided into three equal groups and given a basal roughage diet of shredded wheat straw at a rate of 750 g dry matter (DM) per ewe per day supplemented with a concentrate diet at three amounts, 950 g (low), 1150 g (medium) and 1350 g (high) of DM per ewe per day starting at the beginning of lactation. Ewes were adapted to the diet by feeding daily at a rate of 200 g per ewe during the last 6 weeks of pregnancy. The concentrate was estimated to contain 11⋅8 MJ of metabolizable energy and 182 g of crude protein per kg DM. Ewes and their offspring were housed in a partly enclosed yard. Lambs remained with their dams continuously except for the days of milk yield measurements, when they were separated from the dam for 11 or 12 h. The ewes were examined for subclinical mastitis and the incidence of scouring in lambs was recorded.

Ewes given the high level of concentrate produced more (P < 0⋅05) milk but differences between medium and low groups were significant only up to week 4 of lactation. Total milk yields during the 9 weeks test period were 58⋅5, 70⋅4 and 93⋅3 kg for the low, medium and high groups, respectively. Ewes suckling twins produced more (P < 0⋅05) milk than ewes suckling singles. The rate of weight loss was lower (P < 0⋅01) for ewes given the high feeding regime; these regained their immediate post-lambing body weight by week 10. Sex of lambs and litter size had no effect on body weight loss but ewes nursing twins tended to loose more weight during the 12 weeks suckling period. Lamb growth rates were similar (P > 0⋅05) across treatments. The daily intake of concentrate by the ewes did not affect the incidence of scouring in lambs or mastitis in ewes.

On both economical and biological grounds it is recommended to offer concentrate during the first 9 weeks of lactation at levels >950 g per ewe per day in order to produce an appreciable yield of milk and restore a positive energy balance early in the ewe lactation period.
Two growth models to estimate economic values for food intake capacity in
pigs
Authors: Rohr P. von , Hofer A. , Künzi N.
Published: August 2016

Economic values for average ad libitum food intake
capacity (FIC) were estimated with two different
linear-plateau models. One model based on a constant minimum fat to protein
deposition ratio (Rmin). The other model relied on a
constant minimum marginal ratio between fat and protein deposition
(MR). Economic values were used to define aggregate
genotypes where the driving variables of the growth models were considered as
traits. The consequences of a possible implementation of such aggregate genotypes
were evaluated with a comparison of the expected selection responses for the
different traits.

Economic values for the traits under the two models indicated the same
direction of selection and differed only slightly in their magnitude. For a
FIC below its optimum,
FIC had a positive and
Rmin or MR a negative,
economic value. In this situation the maximum protein deposition rate Pdmax had no
influence on the production costs and therefore an economic value of zero.
Selection emphasis is then mainly put on FIC which
leads to an increase in average daily gain (ADG). If
FIC is above its optimum, economic values for
FIC were negative, positive for Pdmax and equal to
zero for Rmin or MR.
Practically no differences between the selection responses under the two growth
models were observed.

The use of growth models to estimate economic values for
FIC allowed to attribute a positive economic value
to this trait if it is below its optimum. This is not possible when economic
values are estimated with an economic production model.
Genotype with nutrition interactions for carcass composition and meat quality in pig genotypes selected for components of efficient lean growth rate
Authors: Cameron N. D. , Penman J. C. , Fisken A. C. , Nute G. R. , Perry A. M. , Wood J. D.
Published: August 2016

Genotype with nutrition interactions in carcass composition and meat quality traits were examined by testing pigs from four selection lines and a control line on isoenergetic diets, which differed in lysine: energy content. The selected lines resulted from seven generations of selection for high daily food intake, lean food conversion ratio (LFC) and lean growth rate onad-libitumor restricted (LGS) feeding regimes in a Large White population. There were 128 pigs in the study, with 24 pigs per selection line and 32 pigs from a control line. During performance test, 30 to 90 kg, pigs were offered one of three isoenergetic diets, 14·0 MJ digestible energy (DE) per kg dry matter, which differed in ileal digestible lysine: digestible energy (A: 0·40 , C: 0·76 and E: 1·12 g lysine per MJ DE) onad-libitumor restricted (0.75 g/gad-libitumdaily food intake) feeding regimes.

For the majority of performance test, carcass composition and meat quality traits there was no evidence of a genotype with diet or genotype with feeding regime interaction. The selection line with feeding regime interactions for average daily gain, daily food intake and rates of lean and subcutaneous fat deposition were primarily due to no feeding regime effect for the LFC selection line. Selection for high LFC had reducedad-libitumdaily food intake to such an extent that it was not significantly different from daily food intake on a restricted feeding regime, unlike other selection lines in the study. A selection line with feeding regime interaction was detected for muscle рH24hand muscle reflectance, which resulted from the LGS selection line. LGS pigs offered food ad libitum had higher muscle рH24hand lower muscle reflectance than LGS pigs given food at a restricted level, while there was no effect of feeding regime for the other selection lines.

The general absence of genotype with nutrition interactions for traits measured in the study indicated that the ranking of genotypes for performance test traits, carcass composition and meat quality traits will not be dependent on diet or feeding regime. Genotype specific nutritional inputs will also not be required for identification of pigs of high genetic merit, within a genotype. However, diet and feeding regime had significant effects on carcass composition and meat quality traits, such that the estimated mean value of a genotype will be dependent on the diet or feeding regime used to evaluate the genotype.
Comparative evaluation of the meat quality of beef cattle breeds of Indian,
African and European origins
Authors: Gazzola C. , O’Neill C. J. , Frisch J. E.
Published: August 2016

The aim of this study was to rank diverse beef cattle genotypes for meat
quality characteristics and to determine whether that ranking changed depending on
the environment in which the animals were finished. Breed groups, ranging from
100% Bos indicus to 100% Bos taurus content, were derived from Indian zebu
(Brahman), African zebu (Boran), British breeds (Hereford-Shorthorn), continental
breeds (Charolais and Simmental) and Sanga (Tuli and Belmont Red). Heavy steers
(>600 kg) were raised in a tropical environment and finished either on pasture
or in a feedlot.

For striploins (longissimus) from feedlot finished steers, cooking loss was
greatest for zebu (Z) steaks, least for British (B) steaks (P < 0·001), and
intermediate for the other breeds. For striploins from pasture finished steers and
eye rounds (semitendinosus) from both pasture finished and feedlot finished
steers, there were no breed differences in cooking loss.

For both feedlot finished and pasture finished steers, striploin steaks from
B steers were most tender, and Sanga (S) and zebu × continental cross (ZC) steaks
were more tender than Z steaks. Warner-Bratzler initial yields suggested that the
lower toughness of these breeds was due to lower myofibrillar toughness. Peak
force minus initial yield suggested a smaller, opposite effect of increasing
connective tissue toughness associated with increasing Bos taurus content. This
breed effect on connective tissue toughness was more prominent in the eye round
samples. In the feedlot finished steers, Z eye round was as tender as B eye round.
In pasture finished steers, Z eye round had a peak force 1·3 kg lower than B in
contrast to the results for striploin where Z was 1·2 kg higher than B. Sanga eye
round followed the same trend as B relative to Z but to a lesser extent. From the
feedlot, S eye round was more tender than Z eye round and from pasture, S eye
round was the same as Z eye round. There was no evidence of heterosis f or any
meat quality attribute.

These results are best explained in terms of a model incorporating
differential effects of breed on the myofibrillar and connective tissue components
of toughness. The implications of this study are that the tenderness of grilling
and roasting cuts of meat from the predominantly Brahman-based beef herd of
northern Australia can be improved through crossbreeding with any of the taurine
breeds studied.