Compensatory feeding during early gestation for sows with a high weight loss after a summer lactation increased piglet birth weight but reduced litter size

Sows mated in summer produce a greater proportion of born-light piglets (<1.1 kg) which contributes to increased carcass fatness in the progeny population. The reasons for the low birth weight of these piglets remain unclear, and there have been few successful mitigation strategies identified. We hypothesized that: 1) the low birth weight of progeny born to sows mated in summer may be associated with weight loss during the previous summer lactation; and 2) increasing early gestation feed allowance for the sows with high lactational weight loss in summer can help weight recovery and improve progeny birth weight. Sows were classified as having either low (av. 1%) or high (av. 7%) lactational weight loss in their summer lactation. All the sows with low lactational weight loss (LLStd) and half of the sows with high lactational weight loss received a standard gestation feeding regime (HLStd) (2.6 kg/d; day 0–30 gestation), whereas the rest of the sows with high lactational weight loss received a compensatory feed allowance (HLComp) (3.5 kg/d; day 0–30 gestation). A comparison of LLStd (n = 75) versus HLStd sows (n = 78) showed that this magnitude of weight loss over summer lactation did not affect the average piglet or litter birth weight, but such results may be influenced by the higher litter size (P = 0.030) observed in LLStd sows. A comparison of HLStd versus HLComp (n = 81) sows showed that the compensatory feeding increased (P = 0.021) weight gain of gestating sows by 6 kg, increased (P = 0.009) average piglet birth weight by 0.12 kg, tended to reduce (P = 0.054) the percentage of born-light piglets from 23.5% to 17.1% but reduced the litter size by 1.4 (P = 0.014). A subgroup of progeny stratified as born-light (0.8–1.1 kg) or -normal (1.3–1.7 kg) from each sow treatment were monitored for growth performance from weaning until 100 kg weight. The growth performance and carcass backfat of progeny were not affected by sow treatments. Born-light progeny had lower feed intake, lower growth rate, higher G:F, and higher carcass backfat than born-normal progeny (all P < 0.05). In summary, compensatory feeding from day 0 to 30 gestation in the sows with high weight loss during summer lactation reduced the percentage of born-light progeny at the cost of a lower litter size, which should improve growth rate and carcass leanness in the progeny population born to sows with high lactational weight loss.     

The incidence, calf morbidity and mortality due to Theileria parva infections in smallholder dairy farms in Murang'a District, Kenya

A prospective observational study was conducted among smallholder dairy farmers in Murang'a District, Kenya, to estimate the incidence of Theileria parva infections, as well as calf morbidity and mortality caused by the infection. The study was conducted between March 1995 and August 1996, in five cohorts of female calves from birth to six months of age from different agro-ecological zones (AEZs) and grazing-system strata shown previously to have varying prevalences of T. parva infection. A total of 188 smallholder dairy farms with 225 female calves were selected purposively by five AEZ-grazing strata. All recruited calves were visited within the first two weeks of life and thereafter at biweekly intervals up to the age of six months. The mean number of cattle in these smallholder farms was 2.6. Both exotic and indigenous breeds of cattle and their crosses were present, with the former predominating. The incidence (27-54%) of sero-conversion to T. parva in an ELISA test was significantly different (p < 0.05) across the five AEZ-grazing strata and increased with lower elevation and unrestricted grazing. Calf morbidity and mortality were also variable across the AEZ-grazing strata. East Coast fever (ECF) was the highest-incidence cause calf morbidity and mortality (relative to other diseases). There are great differences in the epidemiology of ECF within a small area and this implies that there is need to carefully consider different ECF control strategies in different AEZ-grazing strata.     

A class of potent antimalarials and their specific accumulation in infected erythrocytes

During asexual development within erythrocytes, malaria parasites synthesize considerable amounts of membrane. This activity provides an attractive target for chemotherapy because it is absent from mature erythrocytes. We found that compounds that inhibit phosphatidylcholine biosynthesis de novo from choline were potent antimalarial drugs. The lead compound, G25, potently inhibited in vitro growth of the human malaria parasites Plasmodium falciparum and P. vivax and was 1000-fold less toxic to mammalian cell lines. A radioactive derivative specifically accumulated in infected erythrocytes to levels several hundredfold higher than in the surrounding medium, and very low dose G25 therapy completely cured monkeys infected with P. falciparum and P. cynomolgi.     

Feline rabies. ABCD guidelines on prevention and management

OverviewRabies virus belongs to the genus Lyssavirus, together with European bat lyssaviruses 1 and 2. In clinical practice, rabies virus is easily inactivated by detergent-based disinfectants.InfectionRabid animals are the only source of infection. Virus is shed in the saliva some days before the onset of clinical signs and transmitted through a bite or a scratch to the skin or mucous membranes. The average incubation period in cats is 2 months, but may vary from 2 weeks to several months, or even years.Disease signsAny unexplained aggressive behaviour or sudden behavioural change in cats must be considered suspicious. Two disease manifestations have been identified in cats: the furious and the dumb form. Death occurs after a clinical course of 1–10 days.DiagnosisA definitive rabies diagnosis is obtained by post-mortem laboratory investigation. However, serological tests are used for post-vaccinal control, especially in the context of international movements.Disease managementPost-exposure vaccination of cats depends on the national public health regulations, and is forbidden in many countries.Vaccination recommendationsA single rabies vaccination induces a long-lasting immunity. Kittens should be vaccinated at 12–16 weeks of age to avoid interference from maternally derived antibodies and revaccinated 1 year later. Although some vaccines protect against virulent rabies virus challenge for 3 years or more, national or local legislation may call for annual boosters.     

The effects of bimatoprost and unoprostone isopropyl on the intraocular pressure of normal cats

OBJECTIVE: To evaluate the effects on intraocular pressure (IOP), pupillary diameter (PD), blepharospasm score, conjunctival injection score, and aqueous humor flare score when either 0.03% bimatoprost solution is applied once daily or 0.15% unoprostone isopropyl solution is applied twice daily topically to the eyes of normal cats. MATERIALS AND METHODS: The aforementioned parameters were evaluated daily in each of 12 cats throughout the entirety of the study. During an initial 10-day treatment phase a single eye of six of the cats was treated with 0.03% bimatoprost solution while a single eye of the remaining six cats was treated with buffered saline solution (BSS) once daily. During a second 10-day treatment phase a single eye of six of the cats was treated with 0.15% unoprostone isopropyl solution while a single eye of the remaining six cats was treated with BSS twice daily. Contralateral eyes of all cats remained untreated at all time points. RESULTS: Blepharospasm score, conjunctival injection score, and aqueous humor flare score never rose from a value of 0, for any eye of any cat during the study. The mean +/- SD of IOP for eyes treated with 0.03% bimatoprost solution and BSS were 16.55 +/- 3.06 mmHg and 18.02 +/- 3.52 mmHg, respectively. The mean +/- of PD for eyes treated with 0.03% bimatoprost solution and BSS were 5.7 +/- 1.57 mm and 6.39 +/- 1.78 mm, respectively. The mean +/- SD of IOP for eyes treated with 0.15% unoprostone isopropyl solution and BSS were 15.7 +/- 2.91 mmHg and 17.2 +/- 2.9 mmHg, respectively. The mean +/- SD of PD for eyes treated with 0.15% unoprostone isopropyl solution and BSS were 5.8 +/- 1.43 mm and 6.9 +/- 1.37 mm, respectively. There was no significant difference (P > or = 0.05) in IOP or PD between eyes treated with 0.03% bimatoprost solution vs. eyes treated with BSS. Similarly, there was no significant difference (P > or = 0.05) in IOP or PD between eyes treated with 0.15% unoprostone isopropyl solution vs. eyes treated with BSS. CONCLUSION: Neither once daily topical administration of 0.03% bimatoprost solution nor twice daily topical administration of 0.15% unoprostone isopropyl solution significantly affect the IOP of normal cats. Both 0.03% bimatoprost solution and 0.15% unoprostone isopropyl solution induced no significant ocular side effects in normal cats when dosed over a 10-day treatment period.     

Feline calicivirus

Feline calicivirus (FCV) is an important and highly prevalent pathogen of cats. It belongs to the family Caliciviridae which includes other significant pathogens of man and animals. As an RNA virus, high polymerase error rates convey upon FCV a high genome plasticity, and allow the virus to respond rapidly to environmental selection pressures. This makes the virus very adaptable and has important implications for clinical disease and its control. Being genetically diverse, FCV is associated with a range of clinical syndromes from inapparent infections to relatively mild oral and upper respiratory tract disease with or without acute lameness. More recently, highly virulent forms of the virus have emerged associated with a systemic infection that is frequently fatal. A proportion of FCV infected cats that recover from acute disease, remain persistently infected. In such cats, virus evolution is believed to help the virus to evade the host immune response. Such long-term carriers may only represent a minority of the feline population but are likely to be crucial to the epidemiology of the virus. Vaccination against FCV has been available for many years and has effectively reduced the incidence of clinical disease. However, the vaccines do not prevent infection and vaccinated cats can still become persistently infected. In addition, FCV strain variability means that not all strains are protected against equally. Much progress has been made in understanding the biology and pathogenesis of this important feline virus. Challenges for the future will necessarily focus on how to control the variability of this virus particularly in relation to emerging virulent strains and vaccination.