Evaluation of production efficiencies at pasture of lactating suckler cows of diverse genetic merit and replacement strategy

Feed costs account for the largest proportion of direct cost within suckler beef production systems. By identifying the cow type with enhanced capability of converting grazed herbage to beef output across lactations, suckler cow systems would become more efficient and sustainable. The objective of this study was to estimate grass DM intake (GDMI) and production efficiency among lactating suckler cows of diverse genetic merit for the national Irish maternal index (Replacement Index) which includes cow efficiency components such as milk yield and feed intake. Data from 131 cows of diverse genetic merit within the Replacement Index, across two different replacement strategies (suckler or dairy sourced), were available over two grazing seasons. Milk yield, GDMI, cow live weight (BW) and body condition score (BCS) were recorded during early, mid and late-lactation, with subsequent measures of production efficiency extrapolated. Genetic merit had no significant effect on any variables investigated, with the exception of low genetic merit (LOW) cows being 22 kg heavier in BW than high genetic merit (HIGH) cows (P < 0.05). Beef cows were 55 kg heavier in BW (P < 0.001), had a 0.31 greater BCS (P < 0.05) and 0.30 Unité Fourragère Lait (UFL) greater energy requirement for maintenance compared to dairy sourced beef × dairy crossbred (BDX) cows (P < 0.001). The BDX had 0.8 kg greater GDMI, produced 1.8 kg more milk (P < 0.001), had a 0.8 UFL greater energy requirement for lactation and produced weanlings that were 17 kg heavier in BW than beef cows (P < 0.05). Subsequent efficiency variables of milk per 100 kg BW (P < 0.001), milk per kg GDMI (P < 0.001) and GDMI per 100 kg BW (P < 0.001) were more favourable for BDX. The correlations examined showed GDMI had moderate positive correlations (P < 0.001) with intake per 100 kg BW, net energy intake per kg milk yield, RFI and intake per 100 kg calf weaning weight but was weakly negatively correlated to milk yield per kg GDMI (P < 0.001). No difference was observed across genetic merit for beef cows for any of the traits investigated. Results from the current study showed that, while contrasting replacement strategies had an effect on GDMI and production efficiency, no main effect was observed on cows diverse in genetic merit for Replacement Index. Nonetheless, utilising genetic indexes in the suckler herd is an important resource for selecting breeding females for the national herd and phenotypic performance generated from this study can be included in future genetic evaluations to improve reliability of genetic values.

Differences in intestinal size, structure, and function contributing to feed efficiency in broiler chickens reared at geographically distant locations

The contribution of the intestinal tract to differences in residual feed intake (RFI) has been inconclusively studied in chickens so far. It is also not clear if RFI-related differences in intestinal function are similar in chickens raised in different environments. The objective was to investigate differences in nutrient retention, visceral organ size, intestinal morphology, jejunal permeability and expression of genes related to barrier function, and innate immune response in chickens of diverging RFI raised at 2 locations (L1: Austria; L2: UK). The experimental protocol was similar, and the same dietary formulation was fed at the 2 locations. Individual BW and feed intake (FI) of chickens (Cobb 500FF) were recorded from d 7 of life. At 5 wk of life, chickens (L1, n = 157; L2 = 192) were ranked according to their RFI, and low, medium, and high RFI chickens were selected (n = 9/RFI group, sex, and location). RFI values were similar between locations within the same RFI group and increased by 446 and 464 g from low to high RFI in females and males, respectively. Location, but not RFI rank, affected growth, nutrient retention, size of the intestine, and jejunal disaccharidase activity. Chickens from L2 had lower total body weight gain and mucosal enzyme activity but higher nutrient retention and longer intestines than chickens at L1. Parameters determined only at L1 showed increased crypt depth in the duodenum and jejunum and enhanced paracellular permeability in low vs. high RFI females. Jejunal expression of IL1B was lower in low vs. high RFI females at L2, whereas that of TLR4 at L1 and MCT1 at both locations was higher in low vs. high RFI males. Correlation analysis between intestinal parameters and feed efficiency metrics indicated that feed conversion ratio was more correlated to intestinal size and function than was RFI. In conclusion, the rearing environment greatly affected intestinal size and function, thereby contributing to the variation in chicken RFI observed across locations.

Assessing serum metabolite profiles as predictors for feed efficiency in broiler chickens reared at geographically distant locations

1. The objective of this study was to investigate differences in growth performance, serum intermediary metabolites, acute-phase proteins and white blood cells in low, medium and high-residual feed intake (RFI) chickens. It was also assessed if the environment affects the feed efficiency (FE) and FE-related performance and serum profiles of chickens. 2. Individual body weight (BW) and feed intake (FI) were recorded from d 7 of life. At 5 weeks of age, female and male broiler chickens (Cobb 500) were selected according to their RFI (L1: Austria; L2: UK; n = 9/RFI group, sex and locatity -45on) and blood samples were collected. 3. Chickens at L1 had similar FI but a 15% higher BW gain compared to chickens at L2. The RFI values of female chickens were -231, 8 and 215 g and those of male chickens -197, 0 and 267 g for low, medium and high RFI, respectively. 4. Location affected serum glucose, urea, cholesterol, non-esterified fatty acids (NEFA) and ovotransferrin in females, and serum glucose and triglycerides in male chickens. Serum uric acid and NEFA linearly increased from low to high RFI in females, whereas in males, cholesterol showed the same linear response from low to high RFI. Serum alpha-1-acid glycoprotein and blood heterophil-to-lymphocyte ratio linearly increased by 35% and 68%, respectively, from low to high RFI but only in male chickens at L1. 5. Regression analysis showed significant positive relationships between RFI and serum uric acid (R² = 0.49) and cholesterol (R² = 0.13). 6. It was concluded that RFI-related variation in serum metabolites of chickens was largely similar for the two environments and that serum metabolite patterns could be used to predict RFI in chickens.

Prediction of enteric methane emissions from sheep offered fresh perennial ryegrass () using data measured in indirect open-circuit respiration chambers

Development of effective methane (CH) mitigation strategies for grazing sheep requires accurate prediction tools. The present study aimed to identify key parameters influencing enteric CH emissions and develop prediction equations for enteric CH emissions from sheep offered fresh grass. The data used were collected from 82 sheep offered fresh perennial ryegrass () as sole diets in 6 metabolism experiments (data from non-grass-only diets were not used). Sheep were from breeds of Highlander, Texel, Scottish Blackface, and Swaledale at the age of 5 to 18 mo and weighing from 24.5 to 62.7 kg. Grass was harvested daily from 6 swards on contrasting harvest dates (May to December). Before the commencement of each study, the experimental sward was harvested at a residual height of 4 cm and allowed to grow for 2 to 4 wk. The feeding trials commenced when the grass sward was suitable to zero grazing (average grass height = 15 cm), thus offering grass of a quality similar to what grazing animals would receive under routine grazing management. Sheep were housed in individual pens for 14 d and then moved to individual calorimeter chambers for 4 d. Feed intake, fecal and urine outputs, and CH emissions were measured during the final 4 d. Data were analyzed using the REML procedure to develop prediction equations for CH emissions. Linear and multiple prediction equations were developed using BW, DMI, GE intake (GEI), and grass chemical concentrations (DM, OM, water-soluble carbohydrates [WSC], NDF, ADF, nitrogen [N], GE, DE, and ME) as explanatory variables. The mean CH production was 21.1 g/kg DMI or 0.062 MJ/MJ GEI. Dry matter intake and GEI were much more accurate predictors for CH emissions than BW ( < 0.001, = 0.86 and = 0.87 vs. = 0.09, respectively). Adding grass DE and ME concentrations and grass nutrient concentrations (e.g., OM, N, GE, NDF, and WSC) to the relationships between DMI or GEI and CH emissions improved prediction accuracy with values increased to 0.93. Models based on farm-level data, for example, BW and grass nutrient (i.e., DM, GE, OM, and N) concentrations, were also developed and performed satisfactorily ( < 0.001, = 0.63). These models can contribute to improve prediction accuracy for enteric CH emissions from sheep grazing on ryegrass pasture.

Concentrate supplementation of a diet based on medium-quality grass silage for 4 weeks prepartum: Effects on cow performance, health, metabolic status, and immune function

Because negative energy balance (EB) contributes to transition-period immune dysfunction in dairy cows, dietary management strategies should aim to minimize negative EB during this time. Prepartum diets that oversupply energy may exacerbate negative EB in early lactation, with detrimental effects on immune function. However, with lower body condition score (BCS) cows, it has been shown that offering concentrates in addition to a grass silage-based diet when confined during an 8-wk dry period resulted in increased neutrophil function in early lactation. The aim of this study was to examine if similar benefits occur when concentrate feeding was restricted to a 4-wk period prepartum. Twenty-six multiparous and 22 primiparous Holstein-Friesian cows were offered ad libitum access to medium-quality grass silage until 28 d before their predicted calving dates (actual mean of 32 d prepartum; standard deviation = 6.4). At this time multiparous cows had a mean BCS of 2.9 (standard deviation = 0.12) and primiparous cows a mean BCS of 3.0 (standard deviation = 0.14) on a 1 to 5 scale. Cows were then allocated in a balanced manner to 1 of 2 treatments (13 multiparous cows and 11 primiparous cows on each treatment): silage only (SO) or silage plus concentrates (S+C) until calving. Cows on SO were offered the same grass silage ad libitum. Cows on S+C were offered an ad libitum mixed ration of the same grass silage and additional concentrates in a 60:40 dry matter (DM) ratio, which provided a mean concentrate DM intake (DMI) of 4.5 kg/cow per d. After calving, all cows were offered a common mixed ration (grass silage and concentrates, 40:60 DM ratio) for 70 d postpartum. Offering concentrates in addition to grass silage during the 4 wk prepartum increased prepartum DMI (12.0 versus 10.1 kg/cow per d), EB (+40.0 versus +10.6 MJ/cow per d), and body weight (BW; 640 versus 628 kg), and tended to increase BCS (3.02 versus 2.97). However, postpartum DMI, milk yield, milk composition, BW change, BCS change, serum nonesterified fatty acid, and β-hydroxybutryrate concentrations, health, and corpus luteum measures were unaffected by treatment. The in vitro assays of neutrophil phagocytosis, neutrophil oxidative burst, and interferon gamma production, conducted on blood samples obtained at d 14 prepartum and d 3, 7, 14, and 21 postpartum, were unaffected by treatment. Primiparous cows had higher phagocytic fluorescence intensity at d 14 prepartum and d 3 and 7 postpartum; a higher percentage of neutrophils undergoing oxidative burst at d 3, 7, and 21 postpartum; and a higher oxidative burst fluorescence intensity at d 14 prepartum and d 7, 14, and 21 postpartum compared with multiparous cows. This suggests that neutrophil function of primiparous cows was less sensitive to the changes occurring during the transition period than that of multiparous cows. In conclusion, offering concentrates during the 4-wk period prepartum had no effect on postpartum DMI, milk yield, body tissue mobilization, EB, measures of neutrophil or lymphocyte function, health, or corpus luteum activity.

A comparison of individual cow versus group concentrate allocation strategies on dry matter intake, milk production, tissue changes, and fertility of Holstein-Friesian cows offered a grass silage diet

A diverse range of concentrate allocation strategies are adopted on dairy farms. The objectives of this study were to examine the effects on cow performance [dry matter (DM) intake (DMI), milk yield and composition, body tissue changes, and fertility] of adopting 2 contrasting concentrate allocation strategies over the first 140 d of lactation. Seventy-seven Holstein-Friesian dairy cows were allocated to 1 of 2 concentrate allocation strategies at calving, namely group or individual cow. Cows on the group strategy were offered a mixed ration comprising grass silage and concentrates in a 50:50 ratio on a DM basis. Cows on the individual cow strategy were offered a basal mixed ration comprising grass silage and concentrates (the latter included in the mix to achieve a mean intake of 6kg/cow per day), which was formulated to meet the cow's energy requirements for maintenance plus 24kg of milk/cow per day. Additional concentrates were offered via an out-of-parlor feeding system, with the amount offered adjusted weekly based on each individual cow's milk yield during the previous week. In addition, all cows received a small quantity of straw in the mixed ration part of the diet (approximately 0.3kg/cow per day), plus 0.5kg of concentrate twice daily in the milking parlor. Mean concentrate intakes over the study period were similar with each of the 2 allocation strategies (11.5 and 11.7kg of DM/cow per day for group and individual cow, respectively), although the pattern of intake with each treatment differed over time. Concentrate allocation strategy had no effect on either milk yield (39.3 and 38.0kg/d for group and individual cow, respectively), milk composition, or milk constituent yield. The milk yield response curves with each treatment were largely aligned with the concentrate DMI curves. Cows on the individual cow treatment had a greater range of concentrate DMI and milk yields than those on the group treatment. With the exception of a tendency for cows on the individual cow treatment to lose more body weight to nadir than cows on the group treatment, concentrate allocation strategy had little effect on either body weight or body condition score over the experimental period. Cows on the individual cow treatment had a higher pregnancy rate to first and second service and tended to have a higher 100-d in calf rate than cows on the group treatment. This study demonstrates that concentrate allocation strategy had little effect on overall production performance.

Pig producer perspectives on the use of meat inspection as an animal health and welfare diagnostic tool in the Republic of Ireland and Northern Ireland

BACKGROUND

Currently, there is growing interest in developing ante and post mortem meat inspection (MI) to incorporate measures of pig health and welfare for use as a diagnostic tool on pig farms. However, the success of the development of the MI process requires stakeholder engagement with the process. Knowledge gaps and issues of trust can undermine the effective exchange and utilisation of information across the supply chain. A social science research methodology was employed to establish stakeholder perspectives towards the development of MI to include measures of pig health and welfare. In this paper the findings of semi-structured telephone interviews with 18 pig producers from the Republic of Ireland and Northern Ireland are presented.

RESULTS

Producers recognised the benefit of the utilisation of MI data as a health and welfare diagnostic tool. This acknowledgment, however, was undermined for some by dissatisfaction with the current system of MI information feedback, by trust and fairness concerns, and by concerns regarding the extent to which data would be used in the producers' interests. Tolerance of certain animal welfare issues may also have a negative impact on how producers viewed the potential of MI data. The private veterinary practitioner was viewed as playing a vital role in assisting them with the interpretation of MI data for herd health planning.

CONCLUSIONS

The development of positive relationships based on trust, commitment and satisfaction across the supply chain may help build a positive environment for the effective utilisation of MI data in improving pig health and welfare. The utilisation of MI as a diagnostic tool would benefit from the development of a communication strategy aimed at building positive relationships between stakeholders in the pig industry.

Evaluating the prevalence of tail biting and carcase condemnations in slaughter pigs in the Republic and Northern Ireland, and the potential of abattoir meat inspection as a welfare surveillance tool

Despite extensive utilisation in epidemiological investigations of animal health, to date there has been little consideration of the value of abattoir meat inspection as a pig welfare surveillance tool. This study measured the prevalence of tail-docking, tail biting, carcase condemnations and associated financial losses of the latter (Northern Ireland only) in 36,963 pigs slaughtered in six abattoirs from the Republic of Ireland and Northern Ireland in July and August 2010. Over 99 per cent of inspected pigs had been tail-docked, while 58.1 per cent and 1.03 per cent had detectable and severe tail lesions, respectively. Producer losses resulting from carcase condemnation were estimated to be €0.37 per pig slaughtered. Enhanced capture and utilisation of meat inspection data for use in animal welfare surveillance schemes has the potential to drive improvements in production efficiency and animal welfare. However, significant differences were detected in the prevalence of carcase condemnation conditions between abattoirs and judiciaries (Republic and Northern Ireland). This reflects variation in the criteria and methods of data capture used in meat inspection in different abattoirs. Thus, the meat inspection process needs to be standardised and reformed before it can be reliably utilised in large-scale pig welfare surveillance schemes.

Non-invasive brain stimulation techniques for chronic pain. A report of a Cochrane systematic review and meta-analysis

BACKGROUND

Non-invasive brain stimulation techniques aim to induce an electrical stimulation of the brain in an attempt to reduce chronic pain by directly altering brain activity. They include repetitive transcranial magnetic stimulation (rTMS), cranial electrotherapy stimulation (CES) and transcranial direct current stimulation (tDCS).

AIM

To evaluate the efficacy of non-invasive brain stimulation techniques in chronic pain.

DESIGN

A Cochrane systematic review with meta-analyses.

METHODS

We employed a comprehensive search strategy. Randomised and quasi-randomised studies of rTMS, CES or tDCS were included if they employed a sham stimulation control group, recruited patients over the age of 18 with pain of three months duration or more and measured pain as a primary outcome. Where possible we entered data into meta-analyses.

RESULTS

We included 33 trials in the review (19 rTMS, eight CES and six tDCS). Only one study was judged as being at low risk of bias. Studies of rTMS demonstrated significant heterogeneity. Pre-specified subgroup analyses suggest that low-frequency stimulation is ineffective. A short-term effect on pain of active high-frequency stimulation of the motor cortex in single-dose studies was suggested (standardised mean difference (SMD) -0.40, 95% confidence interval (CI) -0.26 to -0.54, P < 0.00001). This equates to a 15% (95% CI 10% to 20%) reduction in pain which does not clearly exceed the pre-established criteria for a minimally clinically important difference (> 15%). For CES (four studies, 133 participants) no statistically significant difference was found between active stimulation and sham. Analysis of tDCS studies (five studies, 83 people) demonstrated significant heterogeneity and did not find a significant difference between active and sham stimulation. Pre-specified subgroup analysis of tDCS applied to the motor cortex suggested superiority of active stimulation over sham (SMD -0.59, 95% CI -1.10 to -0.08). Non-invasive brain stimulation appears to be associated with minor and transient side effects.

CONCLUSION

Single doses of high-frequency rTMS of the motor cortex may have small short-term effects on chronic pain. The effects do not clearly exceed the predetermined threshold of minimal clinical significance. Low-frequency rTMS is not effective in the treatment of chronic pain. There is insufficient evidence from which to draw firm conclusions regarding the efficacy of CES or tDCS. The available evidence suggests that tDCS applied to the motor cortex may have short-term effects on chronic pain and that CES may be ineffective. There is a need for further, rigorously designed studies of all types of stimulation.

Effects of breed and production system on lameness parameters in dairy cattle

The aim of the present study was to assess the effects of Holstein-Friesian (HF) and Norwegian (N) dairy cattle genotypes on lameness parameters in dairy cattle within different production systems over the first 2 lactations. Following calving, HF (n = 39) and N (n = 45) heifers were allocated to 1 of 3 systems of production (high level of concentrate, low level of concentrate, and grass-based). High- and low-concentrate animals were continuously housed indoors on a rotational system so that they spent similar amounts of time on slatted and solid concrete floors. Animals on the grass treatment grazed from spring to autumn in both years of the study, so that most animals on this treatment grazed from around peak to late lactation. Claw health was recorded in both hind claws of each animal at 4 observation periods during each lactation as follows: 1) -8 to 70 d postcalving, 2) 71 to 150 d postcalving, 3) 151 to 225 d postcalving, and 4) 226 to 364 d postcalving. Sole lesions, heel erosion, axial wall deviation, sole length of the right lateral hind claw (claw length), right heel width, and right lateral hind heel height were recorded as well as the presence of digital dermatitis. The N cows had lower (better) white line and total lesion scores than HF cows. Cows on the high- and low-concentrate treatments had better sole and total lesion scores than cows on the grass treatment. The HF cows had better locomotion scores than N cows. Breed and production system differences were observed with respect to claw conformation, including claw length, heel width, and heel height. Digital dermatitis was associated with worse sole lesion scores and interacted with production system to influence white line lesion scores and maximum heel erosion scores. This study shows that genetic, environmental, and infectious factors are associated with hoof pathologies in dairy cows.

Mapping the cortical representation of the lumbar paravertebral muscles

OBJECTIVE

The aim of this study was to map the cortical representation of the lumbar spine paravertebral (LP) muscles in healthy subjects.

METHODS

Transcranial magnetic stimulation (TMS) was employed to map the cortical representations of the LP muscles at two sites. Stimuli were applied to points on a grid representing scalp positions. The amplitude of motor evoked potentials (n=6) was averaged for each position.

RESULTS

The optimal site for evoking responses in the contralateral LP muscles was situated 1cm anterior and 4 cm lateral to the vertex. Ipsilateral responses were evoked from sites lateral to the optimal site for evoking contralateral responses. Contralateral responses were also obtained from areas anterior to the optimal site.

CONCLUSIONS

Maps of these muscles can be produced. The results suggest discrete contra- and ipsilateral cortical projections. Anterior sites at which excitation can be evoked may indicate projections arising in the SMA are involved.

SIGNIFICANCE

This study provides normative data regarding the cortical representation of the paravertebral muscles and provides a technique for evaluating cortical motor plasticity in patients presenting with spinal pathologies.

Factors identifying pigs predisposed to tail biting

Approximately 5% of pigs slaughtered in the UK have been tail-bitten, leading to welfare and production issues. Tail biting is sporadic and not all pigs tail bite. The aim of this study was to identify factors that are common in pigs that perform tail-biting behaviour, and that might be used in a predictive way to identify such animals.

The behaviour of 159 pigs was observed in the post-weaning period. Pigs were weaned at 4 weeks of age. In the week prior to weaning and at 6 weeks of age each pig was individually tested in a tail chew test (tail chew test 1 and 2, respectively). The tail chew test involved recording the pig's behaviour directed towards two ropes, one of which had been soaked in saline solution and the other not. The production performance of the pigs was recorded from birth to 7 weeks of age. Time spent performing tail-biting behaviour correlated positively with time in contact with the rope in tail chew test 2 (r= 0·224,P< 0·05), and time spent ear biting correlated positively with time spent in rope directed behaviour in tail chew test 1 (r= 0·248,P< 0·01). Pigs that spent as much as 1·5% of their time of more performing tail-biting behaviour were lighter at weaning (26 days) and tended to be lighter at 7 weeks of age compared with pigs that spent less than 1·5% of their time performing tail-biting behaviour (weaning weight: ≥1·5% tail biting 8·96 kg, <1·5% tail biting 9·67 kg,P< 0·05; 7-week weight: ≥1·5% tail biting 15·75 kg, <1·5% tail biting 17·09 kg,P< 0·08). There was no significant difference in birth weight between pigs that spent ≥ or <1·5% of their time performing tail-biting behaviour. Pigs that spent 1·5% of their time or more performing tail-biting behaviour showed significantly lower growth rates between birth and weaning (≥1·5% tail biting 260 g/day, <1·5% tail biting 285 g/day,P< 0·05) but not between weaning and 7 weeks of age (≥1·5% tail biting 343 g/day, <1·5% tail biting 365 g/day,P> 0·05).

The results suggest that pigs that tail bite have some nutritional deficiency that results in performance of foraging behaviour that is expressed in intensive housing as ear/tail biting.