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There is evidence that supplementing methionine has positive effects on uterine environment, oocyte quality and embryo development in cattle. Thus, the objective of this study was to evaluate reproductive traits of cows supplemented with rumen-protected methionine (RPM) during early to mid-lactation in comparison with an untreated control group (CON). An additional focus was on the effect of puerperal diseases on reproductive performance parameters in RPM-supplemented group MET and in CON. A total of 1,709 multiparous Holstein-Friesian cows were enrolled in this field trial conducted on a commercial dairy farm in Slovakia. Cows were allocated at approximately 12 days post-partum (dpp) to either CON or MET, the latter supplemented with 25.0 g-27.2 g RPM per cow per day incorporated into the total mixed ration (TMR) until leaving the study pen at approximately 140 dpp. The amount of RPM was calculated based on individual feed ingredients analysis and adjusted during the study period when TMR changed. Cows were monitored during the post-partum period by vaginal examination (day 5 pp), measuring of beta-hydroxybutyrate in blood (3, 5, and 8 dpp) and by vaginal examination, uterine cytology and measuring of back fat thickness by ultrasound (all at 31 ± 3 dpp). Compared with CON, cows supplemented with RPM did not show better reproduction performance parameters (first service submission rate, days to first service, conception risk, days open 140). Results from binary logistic regression model for the risk of conception showed that metritis had a significant effect, but the supplementation of methionine had not. Results of Cox regression analysis for the odds of conception within 140 dpp revealed only metritis and clinical endometritis as significant factors. In conclusion, supplementation of RPM had no beneficial effect on reproductive performance in this study farm compared with an untreated control group.

BackgroundPregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition. Maternal methionine (Met) supply in non-ruminants during pregnancy can affect offspring development and growth. Thus, the objective of this study was to investigate if increasing Met supply during late-pregnancy affects developmental parameters of the calf at birth and if either maternal Met or colostrum from Met-fed cows alters calf growth. Calves born to Holstein cows individually-fed a basal control [CON; 1.47 Mcal/kg dry matter (DM) and 15.3% crude protein] diet with no added Met or CON plus ethylcellulose rumen-protected Met (MET; Mepron (R) at 0.09% of diet DM; Evonik Nutrition & Care GmbH, Germany) during the last 282 d of pregnancy were used. A total of 39 calves were in CON (n=22 bulls, 17 heifers) and 42 in MET (n=20 bulls, 22 heifers). At birth, calves were randomly allocated considering dam treatment and colostrum as follows: 1) calves from CON cows and colostrum from CON cows (n=21); 2) calves from CON cows and colostrum from MET cows (n=18); 3) calves from MET cows and colostrum from MET cows (n=22); and 4) calves from MET cows and colostrum from CON cows (n=20). All calves were housed, managed, and fed individually during the first 9 wk of life.ResultsDespite greater daily DM intake pre-partum in cows fed MET (15.7 vs. 14.4 +/- 0.12kg/d, P<0.05), colostrum quality and quantity were not affected by maternal diet. At birth, MET calves had greater (P0.05) body weight (BW, 44.1 vs. 42.1 +/- 0.70kg), hip height (HH, 81.3 vs. 79.6 +/- 0.53cm) and wither height (WH, 77.8 vs. 75.9 +/- 0.47cm). In contrast, concentrations of His, Lys, and Asn in plasma were lower (P0.05) in MET calves. Regardless of colostrum source, the greater BW, HH, and WH in MET calves at birth persisted through 9 wk of age resulting in average responses of +3.1kg BW, +1.9cm HH, and+1.8cm WH compared with CON. Average daily

Tryptophan is an essential amino acid, required for protein synthesis, and several metabolic processes in laying hens. Although required, the literature is mixed if tryptophan is considered the third or fourth limiting amino acid for laying hens and research on the tryptophan requirement in laying hens has been limited. The purpose of this experiment was to evaluate the tryptophan requirement of first cycle laying hens from 41 to 60 weeks of age. In total, 270 Hy-line W36 laying hens were randomly allocated to 6 treatments with 15 replicates of 3 birds for each experimental unit. Hens were maintained 3 to a cage (72 sq in/bird) in a multi-teared A-frame cage system within an environmentally controlled building. Hens were provided a 16:8 light schedule and 70 to 80 °F temperature program. A tryptophan deficient basal diet was formulated with corn, corn gluten meal and soybean meal with determined tryptophan, lysine and crude protein concentration of 0.096, 0.873, and 15.0%, respectively. Synthesized l-tryptophan was supplemented to the basal diet in 0.020% increments to generate experimental diets containing 0.096, 0.116, 0.136, 0.156, 0.176, and 0.196% tryptophan respectively. Hens were provided a controlled amount of feed daily resulting in approximately 95g/hen/d. The diet containing the lowest concentration of tryptophan resulted in reduced egg production and was halted at 45 weeks due to low performance with all other dietary treatments reaching the conclusion of the experiment at 60 weeks of age. Hen-housed egg production (HHEP) and mortality were monitored daily. Eggs were collected on two continuous days each week for feed conversion ratio (FCR) calculations and egg quality analysis. Single-slope broken line, multi-slope broken line and quadratic regression were used to estimate tryptophan requirement based on HHEP of the remaining five dietary treatments. Based on HHEP, optimum tryptophan requirement was 154.0, 142.8 and 193.7 mg/hen/d (single-slope broken l

Genetic selection has resulted in laying hens that are producing more eggs while consuming reduced amounts of feed over a laying cycle. As so, it is important to reevaluate the amino acid requirements of these new high performing hens. Valine is an essential amino acid required for protein synthesis, however, research on valine requirement has limited in laying hens. The purpose of this experiment was to evaluate the valine requirement in first cycle laying hens from 41 to 60 weeks of age. In total, 270 Hy-line W36 laying hens were randomly allocated to 6 treatments with 15 replicates of 3 birds for each replicate. Hens were maintained 3 to a cage (72 sq in/bird) in a multi-teared A-frame cage system within an environmentally controlled building. Hens were provided a 16:8 lighting schedule and 70 to 80 °F temperature program. A valine deficient basal diet was formulated with corn and peanut meal with determined valine, lysine and crude protein concentration of 0.515, 0.875, 13.4%, respectively. Synthesized l-valine was supplemented to the basal diet in 0.070% increments, resulting in experimental diets containing 0.515%, 0.585%, 0.655%, 0.725%, 0.795% and 0.865% valine, respectively. Hens were provided a controlled amount of feed daily resulting in approximately 95g/hen/d. Hen-housed egg production (HHEP) and mortality were monitored daily. Eggs were collected on two continuous days each week for Feed Conversion Ratio (FCR) calculations and egg quality analysis. Single-slope broken line, multi-slope broken line and quadratic regression were used to estimate valine requirement based on HHEP, egg weight (EW), egg mass (EM), and feed conversion rate (FCR). Based on HHEP, optimum valine requirement was 591.9, 492.0 and 740.8 mg/hen/d (single-slope broken line regression: Y=80.23 + 0.12219(X-591.9), R2=0.83; multi-slope broken line regression: Y=-0.607+0.1593X-0.1264(X-492.02), R2=0.86; quadratic regression: Y=-0.00019944X2+ 0.295507X-28.3124, R2=0.85).

Tryptophan is an essential amino acid, required for protein synthesis, and several metabolic processes in laying hens. Although required, the literature is mixed if tryptophan is considered the third or fourth limiting amino acid for laying hens and research on the tryptophan requirement in laying hens has been limited. The purpose of this experiment was to evaluate the tryptophan requirement of first cycle laying hens from 41 to 60 weeks of age. In total, 270 Hy-line W36 laying hens were randomly allocated to 6 treatments with 15 replicates of 3 birds for each experimental unit. Hens were maintained 3 to a cage (72 sq in/bird) in a multi-teared A-frame cage system within an environmentally controlled building. Hens were provided a 16:8 light schedule and 70 to 80 °F temperature program. A tryptophan deficient basal diet was formulated with corn, corn gluten meal and soybean meal with determined tryptophan, lysine and crude protein concentration of 0.096, 0.873, and 15.0%, respectively. Synthesized l-tryptophan was supplemented to the basal diet in 0.020% increments to generate experimental diets containing 0.096, 0.116, 0.136, 0.156, 0.176, and 0.196% tryptophan respectively. Hens were provided a controlled amount of feed daily resulting in approximately 95g/hen/d. The diet containing the lowest concentration of tryptophan resulted in reduced egg production and was halted at 45 weeks due to low performance with all other dietary treatments reaching the conclusion of the experiment at 60 weeks of age. Hen-housed egg production (HHEP) and mortality were monitored daily. Eggs were collected on two continuous days each week for feed conversion ratio (FCR) calculations and egg quality analysis. Single-slope broken line, multi-slope broken line and quadratic regression were used to estimate tryptophan requirement based on HHEP of the remaining five dietary treatments. Based on HHEP, optimum tryptophan requirement was 154.0, 142.8 and 193.7 mg/hen/d (single-slope broken l

Genetic selection has resulted in laying hens that are producing more eggs while consuming reduced amounts of feed over a laying cycle. As so, it is important to reevaluate the amino acid requirements of these new high performing hens. Valine is an essential amino acid required for protein synthesis, however, research on valine requirement has limited in laying hens. The purpose of this experiment was to evaluate the valine requirement in first cycle laying hens from 41 to 60 weeks of age. In total, 270 Hy-line W36 laying hens were randomly allocated to 6 treatments with 15 replicates of 3 birds for each replicate. Hens were maintained 3 to a cage (72 sq in/bird) in a multi-teared A-frame cage system within an environmentally controlled building. Hens were provided a 16:8 lighting schedule and 70 to 80 °F temperature program. A valine deficient basal diet was formulated with corn and peanut meal with determined valine, lysine and crude protein concentration of 0.515, 0.875, 13.4%, respectively. Synthesized l-valine was supplemented to the basal diet in 0.070% increments, resulting in experimental diets containing 0.515%, 0.585%, 0.655%, 0.725%, 0.795% and 0.865% valine, respectively. Hens were provided a controlled amount of feed daily resulting in approximately 95g/hen/d. Hen-housed egg production (HHEP) and mortality were monitored daily. Eggs were collected on two continuous days each week for Feed Conversion Ratio (FCR) calculations and egg quality analysis. Single-slope broken line, multi-slope broken line and quadratic regression were used to estimate valine requirement based on HHEP, egg weight (EW), egg mass (EM), and feed conversion rate (FCR). Based on HHEP, optimum valine requirement was 591.9, 492.0 and 740.8 mg/hen/d (single-slope broken line regression: Y=80.23 + 0.12219(X-591.9), R2=0.83; multi-slope broken line regression: Y=-0.607+0.1593X-0.1264(X-492.02), R2=0.86; quadratic regression: Y=-0.00019944X2+ 0.295507X-28.3124, R2=0.85).