The potential for using different crops and pastures to complement perennial ryegrass for dairy production was investigated in non-irrigated dairy systems in Victoria, Australia. Systems modelling indicated that complementary forages could increase profitability (measured as return on assets) to 15%, compared to 9.4% for well-managed perennial ryegrass. This paper describes a farmlet systems experiment designed to test this proposition.

In pasture-based dairy systems increasing forage harvested per hectare supports productivity gains. A 20% increase in forage harvested was achieved on a farmlet consisting of perennial ryegrass plus complementary forages compared to a farmlet with perennial ryegrass only. There are opportunities to increase forage harvest using complementary species but perennial ryegrass remains a key component of the forage base in southern Australia.

Forage options for dairy systems should produce sufficient quantity and quality of forage to support high levels of milk production. Similar milk production per cow was measured on two farmlets consisting of perennial ryegrass plus complementary forages and perennial ryegrass only. Consumption of forage from the double crop implemented was lower than expected, leading to a re-consideration of how to integrate cropping into dryland pasture-based dairy systems.

The profitability of dairy farm systems in southern Australia is closely related to the amount of pasture grown and consumed on-farm by dairy cows. A farmlet experiment was conducted in Victoria, comparing forages complementary to perennial ryegrass with a perennial ryegrass pasture. There was a very small gain in profit from complementary forages but it was associated with higher risks, making it difficult to endorse a change from traditional perennial ryegrass pastures.

This study investigated the effects of increasing the substitution of chopped lucerne hay for 10, 20 or 30% of maize silage on feed intake, rumen pH and fermentation, digestibility, milk production, and feed efficiency of dairy cows in a long term period. We hypothesised that the cow responses would vary with differing ratios of lucerne hay to maize silage in the dairy cow diet. Results indicated that increasing lucerne hay in the place of maize silage did not alter chewing and rumen fermentation, but negatively impacted feed intake and milk production.

Although there has been research on cow–calf interactions, there has been very little work done on the changes in social interactions between cows as they calve. The present study determined whether cows with calves (maternal cows) and pregnant cows had different social preferences. The results showed that maternal cows associated more than non-maternal cows. Quantifying and understanding the group social associations of maternal cows has implications for deriving better knowledge of conditions that lead to improved calf survival.

The conservation and improvement of characteristics through reproduction of native cattle breeds such as Mexican Criollo is of great importance. Differences exist between reproductive functions of Criollo females and those of other cattle breeds. Specific techniques of reproductive management, such as artificial insemination procedures, may be applied to Criollo females in genetic improvement programs.

Summer heat stress lowers fertility in cattle in hot environments by influencing oocyte quality, follicular activity and progesterone (P4) level in blood plasma. However, the mechanisms by which elevated temperature influences corpus luteum function remain unclear. The results of this study suggest that elevated temperature does not negatively affect luteal function, and that the low fertility observed during summer is not due to a direct effect of elevated temperature on luteal cells.

Livestock activities in Mexico have changed over the past 40 years because of increased demand for milk. The aim of this work was to estimate and compare GHG emissions from Mexican dairy cows during 1970–2010. Although GHG emissions in absolute terms increased in the past 40 years, emission intensity decreased due to higher level of production.

The essential oils of some plants can alter rumen fermentation, which in turn enhances the efficiency of nutrient utilisation for ruminants. In this study, the effect of different doses of essential oils extracted from two medicinal plants on rumen fermentation was evaluated. Each essence had a different mode of action in altering the rumen fermentation.

For the treatment of flystrike, the use of a threshold method where a certain percentage of the flock are struck before treatment occurs was compared with the use of a fixed application date. Modelling showed that using a threshold method could improve savings for regions with a longer strike period, and indicate whether to treat or not in regions of low strike risk

Insulin secretion is associated with the type of feeding regime and this may influence body composition. This study investigated the effect of ad libiutm or twice daily feeding on the growth performance, efficiency and body composition in grower-finisher pigs. Feeding pigs twice daily aligned insulin secretion to feeding and may improve feed efficiency and reduce carcass fat.

Dietary fatty acids have profound physiological effects on the in utero development and post-partum performance of animals. This study investigated the effect of feeding one of three types of fatty acids (saturated, n-3 or n-6 polyunsaturated) on the growth and performance of gilt progeny. Modifying the type of fat fed to gilts and their progeny may have significant effects on the growth and performance of pigs.

This feeding study is the third of a series where grain sorghum was hammer-milled through differing screen sizes prior to its incorporation into steam-pelleted broiler diets. The influence of sorghum particle size, as dictated by hammer-mill screen size, on growth performance and nutrient utilisation of broiler chickens offered pelleted diets was more profound than anticipated. Therefore, more attention should be paid to sorghum particle size in practice.

A sustainable novel protein source obtained from larvae of insects to convert waste from food factories was tested in broiler feeds. It was found that this protein source can be used in conjunction and instead of fishmeal and/or soya. No ill effects were observed in the birds and production results were similar or better than those for fishmeal and better than for soya in all instances.

Artificial insemination in goats is a technique that has not been fully transferred in rustic goat farms under extensive management systems. The present study was conducted to clarify the effect of different factors on fertility after insemination in goats reared under commercial conditions. Farm, age, group size, transcervical insemination, number of previous kidding and milk production presented a significant effect on fertility, so that it is difficult to control all the critical aspects of artificial insemination at a farm level.