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This paper examines some of the factors that affect the expression of libido in beef cattle, focusing on the male and the free-ranging situation. The ways in which bull libido is assessed and the relationship between libido test results and fertility are discussed. Genetics play a role in determining libido, but there are many environmental factors affecting its expression, and a number of these factors influence sexual activity in both tests of libido and paddock mating. Herd fertility is multi-factorial and, consequently, it is difficult to draw definitive conclusions about the relationship between libido and fertility. Multiple males increase the expression of libido, but it is uncertain whether this translates into improvements in herd fertility. However, there are consequences for individual bull fertility, as there is ample evidence of inherent differences between bulls. Male:female ratios appear to have minor effects on libido and fertility. Anecdotal evidence indicates that multiple matings with the same or different bulls may reduce the duration of oestrus. Social relationships between bulls can affect the expression of libido, with subordinate bulls being inhibited by the presence of dominant bulls. There is evidence that dominant bulls may achieve more matings at pasture, but this is not necessarily shown in their fertility. Older bulls show greater expression of libido in tests and appear more efficient in serving, although these changes may reflect greater sexual experience. Provided bulls are sexually mature and physically able to mate, age per se appears not to affect fertility, but age interacts with dominance, which can influence fertility. There is evidence of breed differences in expression of libido, but this appears not to be demonstrated in fertility. There is anecdotal evidence that bulls and females prefer to mate with similar genotypes/phenotypes with implications for fertility. Limited research on thermal and nutritional effects indicate some adverse consequences for libido of climatic extremes for unadapted bulls and of over-feeding, but not under-feeding. Limited research has investigated the effects on libido and fertility of multiple stressors associated with relocation; relocation to dramatically different environments has long-lasting detrimental consequences for fertility. Too few studies have been conducted to draw conclusions about the effects of topography and herd dispersion on libido and fertility. Temperament is likely to affect the expression of libido when animals are put into new situations, but this has not been critically researched. In the light of this review, the implications for managing cattle to optimise fertility are discussed and suggestions made as to areas where further research is needed.

Laying hens (64 medium-hybrid ISA Browns), which had been kept to 50 weeks old either in pens or in battery cages, were placed in individual cages which had a tray covered with a thin layer of wood-shavings litter under part of the cage floor; these trays could be seen but not touched by the birds. A majority of previously penned birds, with experience of littered nest sites, responded to the trays by sitting and laying their eggs on the wire floor over them: in the first experiment six out of ten birds showed tray preferences, while in the second experiment it was 16 out of 20. In contrast, the previously caged birds were either indifferent to the trays or avoided them. It was concluded that merely a visual stimulus which had some of the features of a nest site was sufficient to trigger a nest-orientation response in hens with experience of nests, whereas in birds which had only experienced cages the positive response was entirely absent, showing they did not visually recognise a flat, littered surface as a preferred nest site.

Nest-building in the pig is thought to be stimulated by a pre-parturient surge in prolactin. There is concern that sows in crates may experience psychological stress as a result of physical interference with nest-building. Thirty-three gilts were implanted with jugular catheters approximately 10–14 days before expected date of parturition (EPD). On day 5 before EPD, gilts were moved into either conventional farrowing crates without bedding (treatment C; n=16) or pens allowing freedom of movement with bedding (treatment P; n=17). The animals were blood sampled on the day before and the day after introduction to the treatments. Blood and behaviour sampling was resumed 48 h before EPD and continued until 4 h post-commencement of farrowing. As with previous studies gilts in both environments were more active (P

Maternal oestrogen and progesterone have been shown to be important in the initiation of maternal behaviour. Thirty-three Large White x Landrace gilts, housed in groups during pregnancy, were observed and aggressive interactions recorded. Individuals had jugular catheters implanted 14.5 (s.e. 0.34) days before their expected parturition date (EPD). Five days before EPD gilts were randomly allocated and moved to either a conventional farrowing crate (C; without straw, 16 gilts) or a pen (P; 2.1 x 3.1 m2; with straw bedding, 17 gilts). Blood samples were taken at frequencies determined by the proximity to farrowing onset. Piglets were removed at birth and returned 2 h after placental expulsion. The reaction of each gilt to her piglets was monitored. Gilts savaging piglets were sedated with azaperone (n = 8). There was no overall effect of farrowing environment on oestradiol and progesterone concentrations. The pre-farrowing ratio of progesterone to oestradiol was higher for (P) gilts (0.45 vs. 0.25, (P) vs. (C); S.E.D. 0.085, P < 0.05) as was their overall maximum oestradiol level (3.39 vs. 2.29 ng/ml, (P) vs. (C); S.E.D. 0.39, P < 0.01). In contrast to progesterone, oestradiol patterns varied considerably between individuals. Dominance rank value during pregnancy, but not levels of aggression, correlated positively to pre-farrowing oestradiol concentrations. Treatment with azaperone was not related to farrowing environment, piglet weight or litter size. Azaperone treated gilts showed a higher pre-farrowing oestradiol to progesterone ratio (0.55 vs. 0.29, +/- azaperone; S.E.D. 0.10, P < 0.05), significantly higher levels of oestradiol post-partum (0.7 vs. 0.19 ng/ml, +/- azaperone; S.E.D. 0.20, P < 0.001) and significantly lower levels of aggression during pregnancy (1.68 vs. 2.23 aggressive interactions/h, +/- azaperone; S.E.D. 0.15, P < 0.001). The results indicate that there are no major effects of farrowing environment on sex steroid concentrations. Maternal aggression under these conditions appears to be negatively related to aggression during pregnancy, but this is not reflected in plasma concentrations of sex steroids around parturition.

Fifty Bos indicus steers, 2–3 years old, were exposed to aspects of a feedlot environment on their home property for 9 days (pre-exposed). A further 50 steers were placed in a holding paddock for the 9 days (naïve). Twenty steers in each group became 'focal animals' for periodic blood sampling and behaviour observations. The cattle were transported for 15 h (950 km) to an experimental feedlot where they were lot-fed for 100 days, with productivity (liveweight, body condition and feed intakes) and flight speeds recorded at intervals. A subjective fear of humans test was conducted on the pre-exposed group during the 9 days in the yards on the home property and carcass traits were measured on all cattle.Both groups lost substantial weight on the property and during transportation. On the property, the pre-exposed steers lost about 12% of their original liveweight and the naïve about 9%. Transit losses were a further 5 and 4% of pre-transport liveweights, respectively. The steers did not reach their initial liveweights until day 41 of feedlotting. The pre-exposure treatment did not affect final liveweight, but feed intakes were lower for the pre-exposed animals than the naïve ones during the first 16 days of feedlotting, and the pre-exposed steers had superior average daily gains and feed conversion efficiencies. These effects were probably due to a combination of compensation and improved feed digestibility, as a result of the pre-exposed animals being under-fed on the property, but receiving concentrated grain supplement. There was no effect of focal status on productivity.Flight speed and the subjective fear of humans test were significantly correlated. Neither treatment nor focal status affected flight speeds, but flight speeds decreased in the latter part of feedlotting, were highly correlated between days and negatively correlated with average daily gain and intakes.

One hundred and twenty Bos indicus cross steers were allocated to 3 treatments (good, mixed and poor) on the basis of flight speed, as a measure of cattle temperament. The cattle were lot-fed for 100 days and data collected at intervals on their temperament (flight speeds) and productivity (liveweight changes, body condition, pen feed intakes) during this time. After slaughter, data were collected on carcass traits and meat quality. Eating-quality attributes were measured in meat samples from 22 carcasses from each treatment. Flight speeds were highly correlated across animals and within treatments, showed little change in variability over time and were highly repeatable. Flight speed indicated a slight deterioration in temperament with time in the feedlot until day 70, suggesting an increasing fearfulness in the steers. Differences in flight speeds between treatments were maintained throughout the feedlotting period; poor-temperament animals retained poor temperaments and good retained good. Flight speed was correlated with measures of production, and flight speed measured at feedlot induction was a predictor of performance. Correlations and treatment effects showed that cattle with poor temperaments had poorer average daily gains, feed conversion efficiencies, body conditions and dressing percentages compared with those with good temperaments. Reduced performance in the poor-temperament animals may have resulted from their fearfulness and state of high arousal. Treatment (temperament grouping) did not influence carcass traits, but there was evidence of lower initial pH levels and indicators of 'heat-shortening' in the meat of steers with poor temperament compared with those with good temperament. These findings suggest that the poor temperament steers were more susceptible to pre-slaughter stressors than the good temperament animals. However, the meat quality differences were not detected in eating-quality measurements.

Previous work has shown that an acute mid-partum can inhibit oxytocin secretion and prolong delivery in the pig, an effect that is opioid-mediated (Lawrence et al., 1992). However, where gilts were given 5 days to adapt to the farrowing crate, there was little indication that the crate interfered with oxytocin secretion or the progress of parturition relative to gilts farrowing in pens with straw bedding (Lawrence et al., 1995). This experiment aimed to directly assess the extent to which crates or pens affect opioid-control of oxytocin (OT) secretion as a means of measuring stress in the parturient gilt.

Experiments were performed to determine the effect of foetal ejection on the secretion of the neurohypophyseal hormones lysine vasopressin (LVP) and oxytocin (OT), and the adrenocortical hormone cortisol in the parturient pig. As these hormones are all believed to be influenced in some circumstances by stressful stimuli, subsequent studies were carried out in which animals gave birth in putative ideal or suboptimal environments and the consequences of this on hormone release at foetal ejection examined. In Experiment 1, six freely moving gilts gave birth in a strawed pen (1.2 × 1.5 m) during which time blood was withdrawn (3 ml min−1 for 2 h) from an intravenous catheter using an automatic apparatus, and plasma assayed for LVP, OT and cortisol using specific RIAs. Overall LVP and OT release was pulsatile throughout parturition and positively correlated between the birth of the first and last piglet (P < 0.05) but not correlated at other times. Both LVP and OT increased (by 38.8 and 13.5%, respectively; P < 0.05) immediately following each foetal ejection. There were no changes in plasma LVP or OT immediately pre-delivery. Cortisol secretion during parturition was very variable and was not influenced by foetal ejection. In Experiment 2, 33 sows 5 days prior to expected parturition were housed either in strawed pens (2.1 by 3.1 m: Group P; n = 16) or concrete-floored farrowing crates (2.0 by 0.54 m: Group C; n = 17) which prevented the animals from turning around. At birth, blood samples were taken every 15 min for 2 h following Piglet 1 plus an additional sample following each delivery, and assayed as above. Following delivery, plasma LVP in Group C increased from an overall mean of 3.08 to 5.06 pmol l−1 (64.3%) and in Group P from 2.48 to 3.54 pmol l−1 (42.8%). Post-delivery plasma OT in Group C increased from 39.6 to 79.3 (100.3%) and in Group P from 43.8 to 70.2 pmol l−1 (60.3%). These post-ejection increases in both hormones were significantly greater in Group C than Group P animals (P < 0.05). Plasma cortisol was unaffected by delivery in Group C but fell (P < 0.05) following delivery in Group P. These results demonstrate that foetal expulsion results in rapid alterations in neurohypophyseal hormone secretion and that these phenomena are altered by the imposition of differing environments on the parturient pig.

Previous work has suggested that an acute behavioural confinement in mid-partum can inhibit oxytocin secretion and prolong delivery in the pig, an effect that is opioid mediated. The present experiment investigated the effect of longer-term (chronic) behavioural confinement, that has previously been shown to elevate total plasma cortisol, on speed of delivery and on plasma oxytocin and lysine vasopressin concentrations during the peri-parturient period in primiparous pigs (gilts). Five days before their expected parturition (farrowing) date, gilts with preplaced jugular catheters were either confined to farrowing crates that severely restricted maternal behaviour, or housed in pens that permitted free movement and maternal behaviour (e.g. nest building). Blood samples were taken continuously from 24 h before the birth of the first piglet (BFP) to 6 h post-BFP, and for oxytocin on Days 1, 2, and 7 following parturition (Days P1, P2, P7). Both oxytocin and vasopressin were strongly influenced by parturition (P