A dose titration study on the effect of virginiamycin on gilt/sow and piglet performance.

Virginiamycin (VM), a compound with proven performance-promoting properties in pigs, can also be considered as sow performance enhancer. The present dose titration study investigates the long-term effects of VM on gilt/sow and litter performance. A total of 140 healthy gilts, in 35 sets of 2 + 2 siblings each, were used in this trial; gilts in each set were randomly allocated to the four treatments (35 gilts per each treatment group): VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg, VM40 = virginiamycin 40 mg/kg and VM60 = virginiamycin 60 mg/kg of feed. VM was added to the gilt/sow feed for a period starting from 6 months of age up to conception of the fourth parity, covering three complete breeding cycles (pregnancy, lactation and weaning-to-conception interval). The feed given did not contain any other antibacterial agent or performance enhancer. Piglets were given exactly the same quantity of creep feed from the fifth day onwards; it did not contain any antibacterial agent or performance enhancer. The lactation period was the same in all gilts/sows (21 days). Results indicate that VM supplementation of the feed improved gilt/sow performance by: (i) increasing (P < 0.05) the mean body weight at each farrowing, (ii) decreasing (P < 0.05) the mean weight loss from farrowing to weaning, and (iii) decreasing (P < 0.05) the mean weaning-to-conception intervals. VM supplementation of gilt/sow feed also resulted in improved litter size and litter performance in terms of: (i) a higher (P < 0.05) mean number of piglets born alive at each birth, (ii) a higher (P < 0.05) mean number of piglets weaned, (iii) a higher (P < 0.05) mean piglet body weight at each birth, and (iv) a higher (P < 0.05) mean piglet body weight at each weaning. These beneficial effects of VM were more pronounced in the VM40 group.

The effect of salinomycin on health status and performance of sows and their litters: a dose titration study.

Two hundred and fifty gilts and sows (Dalland parent stock) were divided randomly and allocated into the following five experimental groups: SAL0 = negative controls, SAL20 = 20 mg salinomycin per kg of feed, SAL40 = 40 mg salinomycin per kg of feed, SAL60 = 60 mg salinomycin per kg of feed and SAL80 = 80 mg salinomycin per kg of feed. Each gilt and sow was allocated to one of the five groups after the confirmation of the pregnancy using the ultrasonic method and remained under treatment for two consecutive breeding cycles. Throughout the experimental period several parameters related to sow health status, performance and fertility, as well as to health status and performance of their litters were recorded and calculated. Results indicated that salinomycin improves most of the parameters examined, as it leads to significantly higher (P < 0.05): (i) sow body weight gain during gestation; (ii) number of piglets born alive and weaned; (iii) piglet body weight at birth and at weaning, as well as to significantly lower (P < 0.05): (i) prevalence of thin sow syndrome at weaning; (ii) sow body weight loss during lactation; (iii) weaning-to-oestrus interval; (iv) piglet diarrhoea score during lactation; and (v) preweaning mortality. The best results were obtained at the inclusion levels of 40 and 60 mg salinomycin per kg of feed.

A dose titration study on the effect of virginiamycin on specific blood parameters and milk quality in the sow.

The present study investigates the changes in blood cholesterol and total lipids concentrations, as well as changes in milk fat, protein, lactose and total solids content of sows after the long-term administration of virginiamycin (VM) in the feed. Seventy-two (72) healthy Dalland gilts, in 18 groups of four (2 + 2) siblings were used in total. The gilts of each group of siblings were randomly allocated to one of the following four dietary treatments: VM0 = negative control, virginiamycin 0 mg/kg, VM20 = virginiamycin 20 mg/kg feed, VM40 = virginiamycin 40 mg/kg feed and VM60 = virginiamycin 60 mg/kg of feed. Treatments started at the age of 6 months covering three complete breeding cycles (up to the third weaning). The first eight groups of siblings (eight gilts per treatment/32 gilts in total) were used for blood sampling (blood group), while the remaining 10 groups of siblings (10 gilts per treatment/40 gilts in total) were used for milk sampling (milk group). Feeds given at insemination, pregnancy and lactation did not contain any other antibacterial or performance enhancer. The results indicate that all three levels of VM supplementation of gilt/sow feed influenced certain blood parameters by increasing (P < 0.05) both cholesterol and total lipids concentrations on the 30th and 60th day of each pregnancy, at each farrowing and at each weaning. The effect of dietary VM on these blood parameters remained constant throughout three consecutive parities. Moreover, the results indicate a beneficial effect of dietary VM on the milk quality of the sows during the third lactation by increasing (P < 0.05) (i) the mean fat content, (ii) the mean protein content, (iii) the mean lactose content and (iv) the mean total solids content. The highest (P < 0.05) levels in both blood and milk parameters were noticed at the inclusion level of 40 mg/kg of feed.