Conception rate and prolificacy of dairy and crossbred goats under intensive conditions in an arid environment of northern Mexico (26° 06′ 15′′ N; maximum temperature throughout the year 12–42 °C, mean annual precipitation 186 mm, and RH <40% year-round) were examined with respect to season of mating, ambient temperature and rainfall at mating. The database contained 4194 natural services. Conception of goats inseminated with average maximum ambient temperatures >34 °C was significantly higher (P<0·01) than conception of goats inseminated when the average maximum temperature 3 days before breeding was <34 °C. The warmest season favoured conception rate (70% in spring; P<0·01) as compared to cooler seasons (62% and 64% for summer and autumn, respectively). Conception rate of goats bred when rain was present was 14 percentage points lower (P<0·01) compared to mating with no rain. When maximum temperatures on the day of mating were >34 °C, cooler temperatures 1 to 3 days before or after the day of mating were associated with a significant increase in the number of kids born. When the maximum temperature at mating was >36 °C, prolificacy for goats exposed to higher or lower temperatures 1 day before mating was 1·56 and 1·65, respectively (P<0·05). Similarly, when the maximum temperature at mating was 34–36 °C, prolificacy was higher for goats exposed to cooler temperatures as compared to warmer temperatures 1 day (1·64 v. 1·49; P<0·01) or 3 days (1·63 v. 1·48; P<0·01) after mating, with respect to the temperature on the day of mating. Conclusions were that conception rate was not compromised in non-lactating Alpine, Toggenburg, Granadino and Nubian goats subjected to high environmental temperature in an arid region, but the occurrence of rain at mating depressed breeding efficiency of these animals. Additionally, an increment in litter size is expected with cooler temperatures before or after hot days at time of mating.

Hydrogen sulphide (H2S) is a common toxic air pollutant and is emitted from decomposing manure at animal facilities. However, there have been only a few studies of H2S emissions from animal buildings, especially those involving long-term, high-frequency measurements. In the current study, H2S emissions from two, 1000-head pig-finishing buildings in Illinois, USA, were monitored with a high-frequency measurement system for 6 months in 1997 during two, partial, pig-growth cycles. Air sample streams were continuously taken from the pit headspace, and the pit and wall fan exhaust air. Hydrogen sulphide concentration was measured at each location with H2S converters and sulphur dioxide (SO2) analysers during 16 or 24 sampling cycles per day, resulting in 4544 sampling cycles and 219 days of reliable data. Building ventilation rate was the summation of pit fan and wall fan airflow rates. Airflow rates of the underfloor manure pit fans were measured directly with full-size impeller anemometers or calculated from airflow/voltage relationships of the fans. Airflow rates of the wall fans were calculated from fan operation and differential static pressure data and fan performance curves. Mean H2S emission was 0·59 kg/day per building, 0·74 g/day per m2 of pit surface area, or 6·3 g/day per animal unit (AU = 500 kg animal weight). The determination of H2S emission per AU was restricted to 193 days when building occupancy was at least 700 pigs per building. Higher temperatures and building ventilation rates resulted in significantly higher H2S emissions per AU.

Four field experiments were conducted to investigate the effects of seed rate on yield and quality of wheat. Despite some small and inconsistent effects of seed rate on radiation-use efficiency and harvest index, the responses of PAR interception, above-ground biomass and grain yield generally followed similar asymptotic increases as seed rate increased. In one experiment, when nitrogen fertilizer was withheld, biomass and grain yields did not respond to increases in seed rate despite increases in PAR interception. In one experiment, grain yield followed a parabolic response to seed rate with apparent reductions in yield at very high seed rates. Plants compensated for low population densities by increased production and survival of tillers and, to a lesser extent, increased grain numbers per ear. Net tiller production continued until the main stems flowered or later. Effects of seed rate on grain specific weight and thousand grain weight were small and inconsistent. Hagberg falling number increased linearly with seed rate in three experiments, associated with quicker maturation of the crop. Grain protein concentration declined with increase in sowing rate according to linear divided by linear or linear plus exponential models depending on whether the grain yield response was asymptotic or parabolic. Discolouration of the grain with blackpoint increased with seed rate in the most susceptible cultivar, namely Hereward. The economic consequences of these effects on yield and quality are discussed.

Twenty-four multiparous female South African indigenous goats were used. Once a week during the 2nd (weeks 8, 11 and 14) and 3rd (weeks 18, 19 and 20) trimesters, between 08·00 and 15·00 h, four females per treatment were randomly selected and observed every 1 min for time spent grazing, browsing, ruminating and idling. Blood samples were taken once a week during the 2nd (weeks 8, 11 and 14) and 3rd (weeks 18, 19, 20 and 21) trimesters for measurements of some mineral elements and protein metabolites. Goats on natural pasture (NP) grazed 54·8 min (P<0·001) more and browsed 53 min (P<0·001) less than goats on Leucaena leucocephala-grass pasture (LGP) during the 2nd trimester. During the 3rd trimester, goats on NP treatments grazed and idled more (24·7 min, P = 0·004; 15·8 min, P = 0·044, respectively) but ruminated less (−24·1 min, P<0·001) than LGP goats. Time allotted to each field activity by the goats on both treatments within trimester seemed to be dependent on forage species composition while activity between trimesters was possibly influenced by seasons, plant type, herbage quantity, environment and quality, and changes in stage of gestation of the goats. Blood Mg level on NP was higher (P = 0·051) than on LGP during the 2nd trimester while blood Cu and albumin contents on LGP were significantly higher (P = 0·029 and 0·022, respectively) than on NP during the 3rd trimester. Furthermore, blood concentrations of the haematological parameters (except serum protein) on both treatments were within the normal range for goats in the tropics and subtropics and perhaps explain the absence of mineral and nutrient deficiency symptoms. The absence of visible symptoms of mineral deficiency and mimosine toxicity in LGP goats can be attributed to the transfer of DHP-degrading rumen bacteria. The bacteria effectively detoxified mimosine and its metabolites, thereby overcoming chelating tendency of mimosine and its metabolites. Mimosine-susceptible pregnant SAIG can be safely grazed on LGP once their rumen is completely colonized by the DHP-degrading rumen bacteria (Synergistes jonesii).

Three female pigs, one with bilateral and two with unilateral hernia inguinalis, from farms near Río Cuarto, Argentina were studied to assess the hypothesis of intersexuality due to porcine freemartinism. Karyotype analysis of lymphocyte cultures was carried out to look for XX/XY chromosome chimerism. Examination of anatomical and histological characteristics of sexual organs was also performed to describe possible sexual tract abnormalities. The animal with the bilateral hernia inguinalis was shown to be a case of true hermaphroditism. Externally it had female genitalia and inside the abdomen, on the left side, one mature ovary and one testis were located. On the right side of the hernia, a scrotal ovotestis was present. All cytogenetically analysed lymphocytes had the female karyotype. The two animals having unilateral hernia and lymphocyte sexual chromosome chimerism were porcine freemartin.

The study reported examined the physiological changes between two groups of 6 Friesian-cross cows in mid-lactation; one group grazed outdoors without shade, the second group was housed indoors in an open-sided barn and fed cut-and-carry forage from the grazing area. All cows were machine-milked at 05.00 and 15.30 h daily. At 14.00 h dry bulb temperatures averaged 29·5 °C outdoors and 29·0 °C indoors whilst black globe temperatures were 36·2 and 29·5 °C respectively. Relative humidity averaged 76% outdoors and 72% indoors, and the temperature-humidity indices were 79·1 and 78·3, respectively. Cows in the outdoor group had higher rectal temperatures (40·4 v. 39·0 °C; P<0·01), respiratory rates (87·9 v. 62·9 breaths/min; P<0·01) and skin temperatures (41·2 v. 38·2 °C; P<0·01) than those indoors, but lower haematocrit (26·2 v. 34·9%; P<0·01) and haemoglobin levels (10·4 v. 13·2 g/100 ml; P<0·01). Cows in the outdoor group had a higher sweating rate than those indoors (559·7 v. 68·6 g/(m2×h); P<0·01), largely due to a high radiant heat load (as indicated by slightly higher black globe readings). The results of the current study show that the barn used in this study was effective in protecting cows from solar heat. Further field studies to determine the effectiveness of lower cost strategies to reduce heat stress, including showers and shade that can be accessed by grazing cows, are needed.

The objective of the current study was to undertake a preliminary characterization of liveweight components in adult coypus at slaughter. Greenland (14 females, 7 males) and Silver (78 females, 36 males) breeds were grown on a farm south-east of Buenos Aires, Argentina. The animals were slaughtered aged 419±22 days. Liveweight at slaughter was measured and the weights of hot carcass, fur, head, liver, lungs plus heart, digestive tract (with contents) plus reproductive organs and fur length were recorded. The weights of these body components were also expressed as proportion of liveweight, except for the fur length. Data were analysed and the effects of sex, variety, reproductive state within sex and rearing management within sex were included in the model. The age of the animals at the time of slaughter was used as covariate. Breeds differed only in liver weight (P<0·05), where Greenland was 15·9% heavier than Silver; however when comparisons were made as proportion of liveweight, no differences between breeds were found in the variables analysed. Sexual dimorphism was evident in almost all of the characteristics analysed, values for males being higher than for females. Males were 29% heavier at slaughter than females and their carcasses 31·7% heavier. When body components were expressed as proportion of liveweight, male heads were heavier but fur was lighter compared to females. In conclusion, there were differences in body components due to sex but not due to breed. However, most body components when expressed as proportion of liveweight showed no significant differences.