The effect of level of crude protein and available lysine on finishing pig performance, nitrogen balance and nutrient digestibility.

Two trials were conducted to investigate the effect of decreasing the crude protein (CP) content of diets for finishing pigs containing two levels of available lysine on nutrient digestibility, nitrogen (N) balance and production performance. Ten finishing diets containing five levels of CP (on average 144, 155, 168, 182 and 193 g/kg fresh basis) and two levels of available lysine (6.9 and 8.2 g/kg fresh basis) were formulated. The diets were offered to pigs on a performance trial (n = 800 Large White (LW)×Landrace (LR) pigs) from 10 wk of age until finish at 21 wks+5 d of age. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. In addition, a digestibility/N balance trial was conducted using pigs (n = 80 LW×LR) housed in metabolism crates. Digestibility of dry matter (DM), CP, oil, fibre and energy was determined. N balance values were determined through analysis of N content of urine and faeces ('as determined'). N balance values were also calculated using ADG values and assuming that 16% of growth is protein deposition ("as calculated"). Pig performance was poor between 10 and 13 wk of age which indicated that the dietary treatments were nutritionally inadequate for pigs less than 40 kg. There was a significant (p<0.01) quadratic effect of increasing CP level on feed intake, ADG and FCR from 10 to 13 wk which indicated that the lower CP levels did not supply adequate levels of essential or non-essential amino acids. There was no effect of increasing available lysine level throughout the early period, which in conjunction with the response in older pigs, suggested that both 8.2 and 6.9 g/kg available lysine were insufficient to drive optimum growth. There was a positive response (p<0.05) to increasing available lysine level from 13 wk to finish which indicated that 6.9 g/kg available lysine was not adequate for finishing pigs. Energy digestibility decreased with decreasing CP level of diets containing 6.9 g/kg available lysine which may be attributed to the higher fibre content of the lower CP diets. Nitrogen excretion (g/d) was lowered when dietary CP was reduced regardless of whether the values were determined through balance or calculated using ADG. Calculated N excretion decreased linearly (p<0.001) and quadratically (p<0.001) with decreasing dietary CP content. When the N balance figures calculated in this study were compared with those quoted in the Northern Ireland and English Nitrates Directive Action Programmes, N excretion was less per pig (wean to finish) offered a 169 g/kg CP, 8.2 g/kg available lysine diet (2.39 kg vs 3.41 kg (Northern Ireland) and 2.93 kg (England)).

The relationship between the stockperson's personality and attitudes and the productivity of dairy cows.

This study investigated the relationships amongst personality traits and attitudes of 311 dairy stockpeople and the milk yield they obtained. A questionnaire pack consisting of a big-five measure of personality (which includes the traits of extraversion, agreeableness, conscientiousness, emotional stability and intellect), a four-factor attitude questionnaire and associated demographic and production questions was posted out to Northern Ireland dairy farmers. Pearson correlations were used to assess the relationship between personality and attitudes and partial correlations were calculated between milk yield and these psychometric measures. The personality traits of agreeableness and conscientiousness were most strongly correlated to positive attitudes towards working with dairy cows. None of the stockpeople's personality traits were significantly correlated with the milk yield they obtained. Three of the attitude scales, however, were significantly correlated with milk yield; milk yield was related to higher levels of empathy and job satisfaction and lower levels of negative beliefs. These findings, along with previous research, suggest stockperson attitudes may be important in relation to dairy cow welfare and production.

The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein.

An investigation was conducted into the influence of manure composition on the odour emission rate (OER) and the emission rate of ammonia (NH(3)), when diets containing 130, 160, 190 and 210gkg(-1) crude protein (CP) were fed to finishing pigs. A group of four boars and four gilts, housed in environmentally sealed pens, were assigned to each diet for a 23-day experimental period which was replicated three times (n=3). Ventilation air from each pen was sampled for NH(3) and odour, by olfactometry, on four days during the trial period. Simultaneous collections of manure were taken from the surface and base of each pit. The pH and the concentrations of dry matter, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids in the manure were measured. Manure composition differed between samples from the surface and base of the pit (P<0.05). Reducing dietary CP concentration decreased the emission of NH(3) (linear, P<0.001). The acetic acid:propionic acid ratio in manure samples was correlated to OER (r=0.79, P<0.001). There was a quadratic relationship between dietary CP concentration and OER (P<0.05). OER decreased between 210gkg(-1) and 160gkg(-1) CP and increased between 160gkg(-1) and 130gkg(-1) CP. In conclusion, reducing dietary crude protein levels could be used effectively to reduce ammonia emissions and OER, although no significant advantage was to be gained in OER from reducing crude protein level below 160gkg(-1).

Investigation of growth rate variation between commercial pig herds.

The study was designed to provide quantifiable information on both within- and between-herd variation in pig growth rate from birth to slaughter and to examine how this was influenced by moving pigs at a common age to a common environment. Five litters were selected from each of eight pig herds in Northern Ireland with varying growth performance. All eight herds were offered the same nutritional regime. Five pigs (three boars and two gilts) were selected from each litter. In each herd, 22 pigs (12 boars and 10 gilts) were weighed individually, every 4 weeks, from 4 to 20 weeks of age. At 4 weeks of age (weaning) three non-sibling boars were taken from each herd and brought to a common environment where they received medication, were housed individually from 6 weeks of age and offered the same dietary regime. They were weighed and feed intakes were recorded twice weekly. A growth rate difference of 61 g/day (P < 0.001), 112 g/day (P < 0.01) and 170 g/day (P < 0.001) was observed on farm, between the top and bottom quartile of herds during 4 to 8, 8 to 12 and 12 to 20 weeks of age, respectively. This difference in growth rate equated to an average difference in cost of production of ¢13/kg carcass on a birth to bacon unit. When pigs from the different herds were housed in the common environment, large variation in growth performance (143 g/day (P < 0.01) and 243 g/day (P < 0.001) for 8 to 12 and 12 to 20 weeks, respectively) was also observed between the top and bottom quartile of herds. Although feed efficiency was similar, a significant feed intake difference of 329 g/day (P < 0.01) and 655 g/day (P < 0.001) between 8 to 12 and 12 to 20 weeks of age was observed. The variation in growth rate between pigs whether managed on farm or in the common environment was similar (variation in days to 100 kg on farm and in the common environment was 18 and 19 days, respectively). When housed in the common environment, although the top and bottom quartile of pigs converted feed equally efficiently, pigs in the top quartile had significantly higher feed intakes suggesting greater appetites. It is difficult to assess the extent to which these differences can be attributed to genetic effects or pre-weaning environment, and how much the effects of management, disease or genetics contributed to the variation between and within herds.

The influence of diet crude protein level on odour and ammonia emissions from finishing pig houses.

Feed trials were carried out to assess the influence of crude protein content in finishing pig diets on odour and ammonia emissions. Eight pigs (4 boars and 4 gilts), average initial weight 70.8 kg (s.e. 3.167) were housed in two pens that were isolated from the rest of a pig house at University College Dublin Research Farm, Newcastle, Dublin, Ireland. Four diets containing 130, 160, 190 and 220 g x kg(-1) crude protein were fed during six four-week feeding periods (one treatment per room). The first week of the feeding periods served to allow odour build up in the pens and as a dietary adjustment period. The pens had partially slatted floors that were cleaned and had all the manure removed after each four-week period. Odour and ammonia concentrations were measured on days 9, 14, 16, 21 and 23 of each trial period. Odour samples were collected in Nalophan bags and analysed for odour concentration using an ECOMA Yes/No olfactometer. The odour threshold concentration was calculated according to the response of the olfactometry panel members and was displayed in Ou(E)m(-3), which referred to the physiological response from the panel equivalent to that elicited by 40 ppbv(-1) n-butanol evaporated in 1 m(3) of neutral gas. Ammonia concentrations in the ventilation air were measured using Dräger tubes. The odour emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 12.1, 13.2, 19.6 and 17.6 Ou(E)s(-1)animal(-1), respectively (P<0.01). The odour emission rate per livestock unit (500 kg) for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 77.6, 80.0, 115.8 and 102.9 Ou(E)s(-1)LU(-1), respectively (P<0.01). The ammonia emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 3.11, 3.89, 5.89 and 8.27 g x d(-1)animal(-1), respectively (P0.05). Manipulation of dietary crude protein levels would appear to offer a low cost alternative, in relation to end-of-pipe treatments, for the abatement of odour and ammonia emissions from finishing pig houses.

The effect of food deprivation prior to slaughter on performance, behaviour and meat quality.

The effects of repeated food deprivation, prior to slaughter, on performance, feeding behaviour and meat quality of pigs was examined. Three experimental treatments were compared. In treatment 1 pigs had ad libitum access to feed up to the point of loading on the day of slaughter. Treatment 2 involved a 12-h fast prior to slaughter and treatment 3 involved a 20-h fast prior to slaughter. Pigs were slaughtered on a weight basis therefore each pen was emptied over a period of weeks. This meant some pigs experienced repeated food deprivation. The feeding pattern of pigs which were deprived of food for 12 h was very similar to that observed before feed restriction. Pigs which were deprived of food for 20 h spent significantly more time at the feeder post fasting. This was particularly marked during the first 2-3 h when access to feed was restored. Feed deprivation for 12 h prior to slaughter did not adversely affect performance, carcass weight, meat quality or welfare in the present study. Fasting for 20 h reduced carcass weight by 1 kg, which was not statistically significant but could result in financial losses related to carcass weight. The negative effects on meat quality, of repeated feed deprivation, resulted from slower growth rates rather than feed deprivation per se.

The effect of increasing carcass weight of finishing boars and gilts on joint composition and meat quality.

Two hundred and eighty-eight crossbred (3/4 Landrace × 1/4 Large White) pigs, comprising equal numbers of boars and gilts, were housed in single sex groups from 50 kg liveweight to slaughter at liveweights of 92, 105, 118 and 131 kg (carcass weights of 70, 80, 90 and 100 kg). Sample joints from the left longissimus dorsi muscle were obtained at slaughter for dissection and meat quality assessment. As carcass weight increased there were significant (p<0.001) increases in eye muscle area and subcutaneous fat content. Lean content decreased (p<0.001) with increasing carcass weight while intermuscular fat content was not affected. There was a significant interaction between carcass weight and gender with % drip loss in pork from gilts at 100 kg having a higher drip loss than boars and gilts at all other weights. There were small but significant (p<0.01) reductions in ultimate pH with increasing carcass weight. Cooking loss was also reduced (p<0.001) at the heavier weights. There was no effect of carcass weight on shear force or on intramuscular fat. Dry matter (DM) and crude protein (CP) contents of m. L. dorsi increased (p<0.001) at heavier weights while sarcomere length decreased (p=0.001). Compared with boars, gilts had greater eye muscle area (p<0.05), more subcutaneous fat (p<0.001). Meat from gilts in comparison with boars had higher % DM and % CP contents (p<0.001), higher intramuscular fat content and shear force (p<0.05). It is concluded that meat quality may be improved when carcass weight is increased from 70 to 100 kg. ©