It is widely recognized that subclinical mastitis (SCM) is an extensive problem in the dairy industry worldwide. It is of particular concern in developing countries. The aim of this study was to establish the prevalence of SCM in dairy cattle in the urban and peri-urban areas of Kampala, Uganda and to gain information about pathogens and antibiotic resistance patterns. The study was conducted as a field study in 18 smallholder dairy farms in peri-urban Kampala, Uganda. All cows at the farms were physically examined, and cows with signs of clinical mastitis were excluded. Cows (n = 195) were tested with California Mastitis Test (CMT), and udder quarters with CMT score ≥3 (scale 1–5) were milk sampled for bacteriological analysis. To allow further sub-analysis of the results, the stage of lactation, parity, milk production, production type, udder hygiene, and cow breed were recorded. Results indicate that 86.2 % (n = 168) of the tested cows had SCM in one or more quarters. The most common bacteriological outcome was infection with coagulase-negative staphylococci (54.7 %), followed by negative growth (24.9 %) and streptococci (16.2 %); all of which (n = 34) were sensitive to penicillin. Of the tested staphylococci (n = 17), the majority (58.9 %) were positive for penicillinase production. Factors with significant impact on the prevalence of SCM at cow level were the stage of lactation, parity, and production type. The results suggest that the prevalence of SCM in Uganda is substantially higher than reported in previous studies and in other comparable developing countries. This implies that SCM deserves more attention and that improvement in dairy cow husbandry in terms of hygiene and management is necessary.

BackgroundCoagulase negative staphylococci (CNS) are the most common pathogens leading to subclinical mastitis (SCM) in dairy cattle in Uganda. Coagulase negative staphylococci can vary between bacterial species in how they cause disease. The aim of the study was to characterize CNS, from cows with SCM in Uganda, at the species level.FindingsQuarter milk samples (n = 166) were collected from 78 animals with SCM. Bacteriological analyses were carried out at Makerere University, Kampala, Uganda and at the National Veterinary Institute (SVA), Uppsala, Sweden. The most common pathogens found in milk samples from cows with SCM were CNS (31.7%). Two species of CNS were found, S. epidermidis (85%) and S. haemolyticus (15%). Of the CNS isolates, 16/20 (80%) were positive for β-lactamase production (β+).ConclusionsIn milk samples from cows with SCM caused by CNS, S. epidermidis was most prevalent, followed by S. haemolyticus.

Objectives were to determine if low progesterone and increased basal luteinizing hormone for 3 d after injecting prostaglandin F2 alpha would affect precision of preovulatory surges of luteinizing hormone and onset of estrus in Holstein heifers. In experiments 1 and 2, heifers received progesterone devices for 10 d and prostaglandin F2 alpha on the 7th d after inserting progesterone device. For controls, progesterone devices were removed when prostaglandin F2 alpha was injected, and control devices were installed for 3 d. In experiment 1, jugular blood was sampled every 2 or 4 h from injection of prostaglandin F2 alpha until 108 h after removing progesterone to determine basal and peak secretion of luteinizing hormone. In treatment heifers, basal luteinizing hormone tended to increase, and intervals to peak secretion of luteinizing hormone were shorter and more precise than for controls. In experiment 2, heifers were observed for estrus for 30 min every 4 h for 96 h after removing progesterone devices. Intervals to onset of estrus for experimental heifers were shorter and more precise than for controls. After exogenous prostaglandin F2 alpha, 1 to 2 ng of progesterone per milliliter of serum for 2 to 3 d allows increased basal luteinizing hormone and is associated with increased precision of preovulatory secretion of luteinizing hormone and onset of estrus. This may be an acceptable method to control ovulation precisely for fixed time insemination of cattle.

ContentsThe study investigated the influence of selected husbandry factors on interval to resumption of post-partum cyclicity among dairy cows in urban and peri-urban Kampala. A prospective study of 85 day post-partum period of 59 dairy cows in open (n = 38) and zero grazing (n = 21) systems was conducted on 24 farms. Cows of parity 1–6 were recruited starting 15–30 days post-partum. Progesterone (P4) content in milk taken at 10–12 day intervals was analysed using ELISA. The cow P4 profiles were classified into ‘normal’ (< 56 days), ‘delayed’ (> 56 days), ‘ceased’ or ‘prolonged’ (if started < 56 days but with abnormal P4 displays) resumption of luteal activity and tested for association with husbandry and cow factors. Of the 59 cows, luteal activity in 81.4% resumed normally and in 18.6%, delayed. Only 23.7% maintained regular luteal activity, while the others had ceased (10.2%), prolonged (37.3%) or unclear luteal activity (20.3%). There were no differences between open and zero-grazed cows. Milk production was higher (p < 0.05) in zero than open grazing, in urban than peri-urban and in cows fed on brew waste (p < 0.001) compared with mill products and banana peels. Results suggest that luteal activity resumes normally in a majority of cows, although only a minority experienced continued normal cyclicity once ovulation had occurred, in the two farming systems irrespective of feed supplements or water, and that supplementing with brew waste is beneficial for milk production.

Artificial insemination (AI) is widely used in livestock industries to breed for desirable characteristics and increase yields. The standard practice of storing and transporting bovine semen uses liquid nitrogen (LN), a scarce commodity in many regions of the world. This study explored the feasibility of using dry ice, a more readily available alternative. We developed equipment that dispenses dry ice from widely available liquid carbon dioxide (LCO2) tanks into an easily transportable device. In vivo fertility results with a dry ice cold chain showed no statistical difference to the conventional LN method. In vitro bovine semen analyses also showed that storage under these conditions minimally affects characteristics associated with fertility. A dry ice cold chain system could leverage the global availability of LCO2 to expand the reach of AI and other cold storage applications of biological materials in low-resource settings.