Humans have the ability to replicate the emotional expressions of others even when they undergo different emotions. Such distinct responses of expressions, especially positive expressions, play a central role in everyday social communication of humans and may give the responding individuals important advantages in cooperation and communication. The present work examined laughter in chimpanzees to test whether nonhuman primates also use their expressions in such distinct ways. The approach was first to examine the form and occurrence of laugh replications (laughter after the laughter of others) and spontaneous laughter of chimpanzees during social play and then to test whether their laugh replications represented laugh-elicited laugh responses (laughter triggered by the laughter of others) by using a quantitative method designed to measure responses in natural social settings. The results of this study indicated that chimpanzees produce laugh-elicited laughter that is distinct in form and occurrence from their spontaneous laughter. These findings provide the first empirical evidence that nonhuman primates have the ability to replicate the expressions of others by producing expressions that differ in their underlying emotions and social implications. The data further showed that the laugh-elicited laugh responses of the subjects were closely linked to play maintenance, suggesting that chimpanzees might gain important cooperative and communicative advantages by responding with laughter to the laughter of their social partners. Notably, some chimpanzee groups of this study responded more with laughter than others, an outcome that provides empirical support of a socialization of expressions in great apes similar to that of humans.

Primary growths of perennial ryegrass (Lolium perenne) were cut on 22 May and 12 June and wilted for 24 h prior to ensiling. A 40 : 60 mixture of the two silages was offered ad libitum with two pelleted supplements. Supplement Ba was a mixture of (dry matter (DM) basis) 932 g rolled barley and 68 g fish meal per kg. Supplement SBP/FF consisted of 555 g unmolassed beet pulp, 314 g extracted rice bran, 56 g fat prills and 75 g soya-bean meal per kg. The factorial combination of the two supplements (Ba and SBP/FF) given at two levels, 6 kg DM (L) or 12 kg DM (H), provided the four treatments imposed over weeks 3 to 10 of lactation on 40 British Friesian cows. During weeks 12 to 20 of lactation (post-experiment period) the cows were given an equal mixture of the two concentrates at 9 kg DM per day.Supplement Ba contained less ash (31 v. 94 g/kg), acid-detergent fibre (68 v. 218 g/kg) and fat (29 v. 77 g/kg) but more starch (558 v. 89 g/kg) and digestible organic matter in the dry matter in vitro (DOMD) (781 v. 627 g/kg) than SBP/FF. The concentration of total nitrogen (N) was similar at 25-6 g/kg. Silage had a DOMD of 643 g/kg, a pH of 3-8 and proportionately 0-82 of fermentation acids as lactic acid.Apparent digestibility of gross energy was higher for Ba diets (0-748) than for SBP/FF (0-704). Cows given SBP/FF ate 0-9 kg more silage DM than those given Ba (P < 0-01) but there was no difference in digestible energy intake or in substitution rate (-0-37 kg silage DM per kg additional supplement DM).Increasing the amount of supplement increased milk yield by 3-9 kg/day (P < 0-001). Cows given SBP/FF yielded on average 1-6 kg more milk than those given Ba (P < 0-05). However, this increased output consisted almost entirely of lactose and water as a result of a high concentration of fat in the milk of cows given Ba at the low level (46-3 g/kg). Further, the concentration of protein was less with SBP/FF (28-0 g/kg) than with Ba (29-2 g/kg).The effects of SBP/FF in early lactation were translated into a positive residual effect in mid lactation equivalent to the immediate effect. In contrast, raising yield by increasing the amount of supplement did not result in increased output subsequently.The results show that a supplement of fibre and fat despite having a lower digestibility than barley can produce more milk but a similar yield of fat and protein provided silage is offered ad libitum.

No abstract

No abstract

No abstract

Silages were made from the primary growth of perennial ryegrass (Lolium perenne) or red clover (Trifolium pratense) and were given ad libitum to 52 British Friesian cows, together with 70 kg dry matter per day of a barley/ground maize/soya bean supplement in 2 years. Twenty of the cows were used in both years, providing a total of 72 observations. Three treatments were imposed during weeks 3 t o 20 of lactation: red clover silage, (RC/RC); red clover silage, weeks 3 to 10, grass silage weeks 12 to 20 (RC/PRG); grass silage (PRG/PRG).Apparent digestibility of the gross energy assessed in lactation weeks 14 and 15 was slightly lower for red clover than for perennial ryegrass (0·683, 0·706 and 0·701 for treatments RC/RC, RC/PRG and PRG/PRG respectively). There was no effect of previous treatment on the digestibility of perennial ryegrass diets (RC/PRG v. PRG/PRG). Cows given red clover silage consumed proportionately 1·22 of the dry matter and 1·09 of the digestible energy ingested by those given perennial ryegrass. The intake of perennial ryegrass in mid lactation was similar, irrespective of early lactation treatment.During weeks 3 to 20, cows given red clover yielded 1·9 kg more milk than did those given perennial ryegrass (P < 0·01). However, this milk had a significantly lower concentration of fat (P < 0·01; 37·2 and 41·2 g/kg for treatment RC/RC and PRG/PRG respectively). In mid lactation the cows that had received red clover silage in early lactation (RC/PRG) had the lowest yield of milk, milk fat, protein and lactose and the difference between this treatment and PRG/PRG was significant for milk and milk fat yields (P < 0·05).Red clover silage rather than perennial ryegrass silage of similar digestibility resulted in higher silage intake and higher yields of milk, milk protein and lactose. However, the strategic use of red clover silage to increase yield in early lactation did not induce positive residual effects in mid lactation; rather, there was evidence of a negative effect on milk and milk-fat yield.

No abstract

1.A primary growth of perennial ryegrass was cut on 8 to 11 May (early) or on 12 June (late) for comparison with the primary growth of a tetraploid red clover, which was cut either on 1 or 2 June (early) or on 28 June (late). The crops were ensiled, after wilting for about 4h, with the addition of formic acid at 2-21/t fresh crop. The silages were given ad libitum alone or with rolled barley at 11-5 g dry matter per kg live weight to 40 British Friesian steers initially 3 months old and 108 kg live weight. 2. On average there was no significant difference in digestibility between perennial ryegrass and red clover.However, the rate of decline in digestibility with time was greater with perennial ryegrass than with red clover. 3. Calves given silage of red clover as the sole feed ate more dry matter and grew faster than calves given grass silage (P<0-001) but supplementation with barley reduced the intake of red clover silage to a greater extent than that of perennial ryegrass silage. Barley supplementation increased live-weight gain of calves given perennial ryegrass from 0-32 to 0-83 kg/day and that of calves given red clover from 0-63 to 0-99 kg/day (interaction P<005). The results did not indicate a higher net efficiency of utilization of the legume. Date of cut had no significant effect on dry-matter intake but earlier cutting resulted in an increase in live-weight gain from a mean of 0-61 to 0-77 kg/day (P<0-001). 4. The results show that high rates of live-weight gain (0-74 kg/day) can be achieved by calves given silage of red clover and that earlier cutting of herbage for silage does not always result in higher intakes of dry matter. Supplementation of silages with barley can reduce markedly the difference in intake and live-weight gain apparent when the silages are given as sole feeds.