More efficient and economical production systems are needed to improve the sustainability of dairy farms. One concept to consider is using perennial cows. Perennial cows are those that maintain a relatively high milk production for >or=2 yr without going through the typical dry period followed by calving. Farm records show that some cows have produced over 20 kg/d after 4 yr of continuous lacta...

Milk yield per cow has more than doubled in the previous 40 years and many cows now produce more than 20,000 kg of milk per lactation. The increase in production should be viewed with concern because: i) the increase in milk yield has been accompanied by declining fertility, increasing leg and metabolic problems and declining longevity; ii) there are unfavourable genetic correlations between mi...

In the present study a deterministic bio-economic model was used to estimate economic values for reproduction traits (conception rate, twining rate and litter size), production traits (body weight of kid sold at 6.5 months, annual cashmere weight, body weight of doe and annual milk yield) and longevity (survival of doe, survival of kid until weaning and survival of kid until sale age at 6.5 mon...

This animal simulation model, named e-Cow, represents a single dairy cow at grazing. The model integrates algorithms from three previously published models: a model that predicts herbage dry matter (DM) intake by grazing dairy cows, a mammary gland model that predicts potential milk yield and a body lipid model that predicts genetically driven live weight (LW) and body condition score (BCS). Bo...

In a 2-yr study, we evaluated the effect of different forage allocations on the performance of lactating beef cows and their calves grazing stockpiled tall fescue. Allocations of stockpiled tall fescue at 2.25, 3.00, 3.75, and 4.50% of cow-calf pair BW/d were set as experimental treatments. Conventional hay-feeding was also evaluated as a comparison to grazing stockpiled tall fescue. The experi...

Replicated cow herds of 15 Angus x Hereford (AH) and 15 Brahman x Hereford (BH) F1 cows each were placed on native rangeland (NR) or native rangeland-complementary forage (NRCF) systems. The NR was 8.1 ha of sagebrush-mixed prairie per cow-calf unit and the NRCF used the same mixed prairie complemented by .4 ha of double-cropped winter wheat and summer annual forage replacing about 30% of the m...

A model to calculate the economic losses of mastitis on an average Dutch dairy farm was developed and used as base for a tool for farmers and advisors to calculate farm-specific economic losses of mastitis. The economic losses of a clinical case in a default situation were calculated as euro210, varying from euro164 to euro235 depending on the month of lactation. The total economic losses of ma...

The objective of this trial was to measure performance of paired pens of lactating Jersey and Jersey-Holstein crossbred (JX) vs. Holstein (H) cows over a year in a Wisconsin confinement dairy herd. Average daily milk yield of JX was 5.5 kg/ cow less than H, whereas average milk fat and true protein percentages were 0.61 (4.26 vs. 3.65%) and 0.19 (3.05 vs. 2.86%) percentage units, respectively, ...

Twoand 3-year-old beef bulls were exposed to 25 or 40 beef cows on pasture during a 90-day breeding period. Reproductive performance of bulls by age of bull and size of cow group was evaluated in terms of percentage calf crop. Results indicated that reproductive performance of 2-year-old bulls was higher, but not significantly different (P>.05), than that of 3-year-old bulls. The percentage cal...