The growth performance of growing pigs during feed restriction and re-alimentation in a humid tropical environment

Thirty two crossbred (large white x landrace) pigs were used in a 56 days restriction and 56 days realimentation study to evaluate the effect of restricting growing pigs at 90, 80 and 70% of the ad libitumfeed intake of the control. The pigs averaged 35.23 ± 0.560 kg at the start of the study. There were four treatments (control, 90, 80 and 70%). Each treatment had eight pigs allotted to 2 replications of fourpigs each. The pigs received a 16% crude protein and 12.08 MJME/kg diet. Results indicated that average daily gains (ADG) of the control pigs were significantly superior to the others during the restriction period. However, at the end of the 56 days re-alimentation, pigs on the 80% and 70% feeding regime had superior ADG than the pigs on the control and 90 percent feeding regime. Data on the body length (BL) and height at shoulders (HS) followed the same trend as observed for ADG. Feed intakes of pigs were significantly affected during the restriction and re-alimentation period. There was a significant (p < 0.05) decrease in feed intake as level of restriction increased. Also, during realimentation pigs on the 70% level had the highest feed intake. Pigs on the 80% level of restriction had the best feed cost/kg gain values at restriction and re-alimentation. It is concluded that restrictinggrowing pigs at 80% of the ad libitum intake of the control yields best performance and economic benefit

Testicular development and relationship between body weight, testis size and sperm output in tropical boars

Ten boars selected from each group of local Nigerian (LNB), Large White (LW) and LNB x LW (F1) crossbred boars were studied to determine the pattern of testicular development by external testicularmeasurements (length and width of testis) and to find out the relationship between external testicular dimensions body weight and sperm output. The results showed that LW boars were superior to bothLNB and LNB x LW (F1) boars in all testicular and body weight measurements, while LNB x LW (F1) boars showed remarkable improvement over the LNB parent in all measurements. Rapid growth of the testis occurred in LNB from 14 – 30 weeks of age and 14 – 32 weeks of age in the crossbreds. Rapid growth of testis occurred from 12 – 32 weeks in the LW boars. These periods coincided with the phaseof rapid gain in body weight in the various groups. Significant (P < 0.05) between genotype differences were observed in body weight and testicular measurements. Sperm output/48h was highest in LW boarsand lowest in LNB boars. Correlations between body weight testicular measurements and sperm output per 48 h were positive and highly significant (P < 0.01) in all groups with r2 value ranging from 0.74 –0.90. Sperm output was highly correlated (P < 0.01) with body weight in all genotypes with r2 values ranging from 0.85 – 0.91. The results generally indicate that measurements of external testis dimensions, body weight and sperm output characteristics can accurately guide the assessment of the reproductive performance of boars