Influence of Routing Treatments on Cows' Visits to an Automatic Milking System,their Time Budget and Other Behaviour

Four cow routing treatments related to fully automatic milking were compared consecutively in one group of 24 Holstein Friesian cows. The objective of the experiment was to investigate how cow traffic towards the automatic milking system (AMS) should be routed and whether a preselection or a waiting area in front of the AMS should be used. The treatments were (1) free routing with selection of cows in the AMS (FREE); (2) free routing with a preselection system in front of the AMS (FREE_SS); (3) free routing with a preselection system and a waiting area in front of the AMS (FREE_WA); and (4) one-way gates resulting in forced routing with preselection and a waiting area in front of the AMS (FORCED_WA). Evaluation of the treatments revealed that FREE may be questionable with regard to the cows' visiting frequency to the AMS and that the use of a waiting area in combination with free routing (FREE_WA) may slow down the passing through the AMS. FORCED_WA may be the best option in relation to the cows' use of the AMS, but this traffic system seems to postpone or even thwart the feeding. The treatment that appears to give the best results is FREE_SS. The type of AMS visit appeared to have a marked influence on the cows' subsequent behaviour. Cows returned to the AMS sooner after non-milking visits and failed attachments (P<0.01). This increases the occupation rate of the AMS and may induce some extra unrest in the herd.     

Measurement of enteric methane from ruminants using a hand-held laser methane detector

Abstract

This study investigated the effectiveness of the proprietary laser methane detector (LMD) in enteric methane monitoring from individual dairy cows and sheep. Three experiments were carried out. First, the relationship between LMD and indirect open-circuit respiration calorimetric chamber measurements was tested. Sensitivity and specificity for cows were 95.4% and 96.5%. For sheep, sensitivity was 93.8% and specificity was 78.7%. Second, the effect of cow's activity on enteric methane emissions was investigated. During drinking and feeding, cows produced significantly more (p<0.001) methane emissions than when idle. Third, effect of different micrometeorological factors on LMD measurements under outdoor grazing conditions was investigated. Wind speed, relative humidity, pressure and wind direction relative to methane point-source had significant effect on methane measurements (p<0.001) under outdoor conditions. With further validation, the LMD has potential to provide reliable estimates from ruminants and hence provide a useful technique for on-farm monitoring and decision support for greenhouse gas mitigation strategies.     

Towards the development of a bioeconomic stocking model for the semi‐arid savanna of KwaZulu‐Natal

Abstract

Rainfall variability is a major determinant of system dynamics and profitability of livestock enterprises in arid and semi‐arid environments. Range managers consequently require detailed information on the financial and ecological implications of various stocking strategies in order to formulate viable management systems. Data collected over seven seasons (1986–1993), from a series of extensive grazing trials in the semi‐arid savanna of KwaZulu‐Natal with cattle stocked at three rates (0.17, 0.23 and 0.30 LSU ha^?1) were used to develop a bioeconomic stocking model (LOWBEEF). The model comprised two biological sub‐models (BEEF and GRASS), and an integrated economic component. The BEEF sub‐model related seasonal live mass gain to stocking rate and rainfall. The GRASS sub‐model related residual herbage at the end of summer to summer stocking intensity, range condition (indexed as the sum of proportions of three key forage species, Themeda triandra, Panicum maximum and P. coloratum) and rainfall. The period over which supplementary feeding would be required to maintain cattle mass was related to residual summer herbage mass. The biological sub‐models were linked to an economic component model (ECON) to reflect the influence of various environmental and economic parameters on profitability.     

Streptococcus equi subsp. zooepidemicus isolates from equine infectious endometritis belong to a distinct genetic group

Streptococcus equi subsp. zooepidemicus is the pathogen most commonly isolated from the uterus of mares. S. zooepidemicus is an opportunistic pathogen and part of the resident flora in the caudal reproductive tract. The aim of this study was to investigate whether a genotypically distinct subpopulation of S. zooepidemicus is associated with endometritis in the mare, by genotyping and comparing uterine S. zooepidemicus strains with isolates from the vagina and clitoral fossa. Mares with (n = 18) or without (n = 11) clinical symptoms of endometritis were included. Uterine samples were obtained using a guarded endometrial biopsy punch, whereas a swab was used to recover samples from the cranial vagina and the clitoral fossa. If S. zooepidemicus was present, up to three colonies were selected from each anatomical location (max. 9 isolates per mare). Bacterial isolates were characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). S. zooepidemicus was isolated from the endometrium of 12 mares. A total of 88 isolates were analyzed by PFGE: 31 from the endometrium, 26 from the cranial vagina and 31 isolates from the clitoral fossa. For MLST 21 isolates were chosen. Results demonstrated a higher genetic similarity of the isolates obtained from infectious endometritis compared to isolates obtained from the caudal reproductive tract. In conclusion, we demonstrate for the first time that a genetically distinct group of S. zooepidemicus is associated with infectious endometritis in the mare.     

The Bolivian “Altiplano” and “Valle” sheep are two different peripatric breeds

Forty-nine sheep belonged to the Andean Altiplano region (“Altiplano”) and 30 in the lowland regions of Bolivia (“Valle”), aged 1 to 4 years, were wool sampled to determine the extent of difference between these local breeds. Fibre length and the percentage of each type of fibre (long-thick, short-thin and kemp), yield and fibre diameter were measured. There was a highly significant difference between the two sheep populations that were not clearly separated in the first two principal component of a principal components analysis (PC); the first PC explained 67.1 % and the second PC explained 26.6 % of the total variation. The variables that contributed most to the separation of the sheep populations were the percentage of long-thick and short-thin fibres in the first PC and yield in the second PC. A discriminant analysis, which was used to classify individuals with respect to their breeding, achieved an accurate classification rate of 84.2 %. Thus, the Altiplano and Valle sheep must be viewed as two closely peripatric breeds rather than different “ecotypes”, as more than 80 % could be correctly assigned to one of the breeds; however, the differences are based on composition of long-thick and short-thin fibres and yield after alcohol scouring.     

Use of a staphylococcal vaccine to reduce prevalence of mastitis and lower somatic cell counts in a registered Saanen dairy goat herd

This investigation evaluated the efficacy of a bacterin in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a dairy goat herd. Does were vaccinated or left as controls, and the levels of mastitis and SCC monitored over 18 months. Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI). The infection rate was 1.64 IMI/doe among vaccinates, which tended to be lower (P < 0.12) than controls (2.67 IMI/doe). The spontaneous cure rate of IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than controls (0.6 cures/doe; P < 0.043). Average SCC of milk samples from vaccinates tended to be lower than that of controls (1274 × 10³/ml vs. 1529 × 10³/ml, respectively) (P < 0.10). Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.     

Influence of varying dietary electrolyte balance on broiler performance under tropical summer conditions

A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na⁺+K⁺–Cl^?) mEq/kg of diet were prepared by adding NaHCO₃ and/or NH₄Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO₂ and HCO₃ concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO₃. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers.