José Fernando Piva Lobato

Effect of gentle handling on the reactivity of zebu crossed calves to humans

The effects of gentle handling of zebu crossed beef calves by humans were studied. Forty Nelore × European male and female calves, born in spring and reared under free-range conditions, were randomly divided into two groups: treatment (n = 20) and control (n = 20). The treatment animals were individually exposed at 1–2 months of age to one daily session of 90 s of gentle handling in the crush for 10 days, during 3 weeks. A response-to-humans test was conducted in the pound 3 days after the handling sessions. Animals were individually introduced into the pound and their reactions to two stationary experimenters were videorecorded and quantified. Non-handled calves moved more (P < 0.01) and looked less (P < 0.01) at the experimenters than handled ones. More non-handled animals showed aggressive behaviour towards humans (P < 0.05). None of the handled calves attempted to escape, while 30% (n = 6) of the non-handled calves did (P < 0.05), and, in fact, escaped by jumping over the wall or gates of the pound. Although production traits of zebu crossbred cattle are well recognized, most farmers in the south of Brazil complain of the difficulty of handling these animals due to their ‘wild temperament’. Gentler handling methods could improve the ease of handling of these animals, diminishing losses due to injury of animals, as well as labour costs.

Efeito de sistemas de alimentação no ganho de peso e desempenho reprodutivo de novilhas Nelore acasaladas aos 17/18 meses

Using a linear statistical model (GLM/SAS) the reproductive performance and growth of 480 Nellore heifers were evaluated from the age of 7.5 to 17/18 months under four feeding systems during the dry period (96/05 to 96/10): Brachiaria brizantha cv. Marandu pasture (B); Brachiaria brizantha cv. Marandu pasture + Anipro (BA); Pennisetum americanum cv. (L.) Leeke (Pearlmillet) (M) and Brachiaria brizantha cv. Marandu pasture + Sal Ouro (BS). At the end of supplementation all heifers were moved to a paddock of Panicum maximum cv. Mombaca pasture, 1 AU/ha, from 96/10 until the end of the mating season (97/03 to 97/05). Parameters like liveweight (LW), body condition score (BCS), liveweight daily gain (LDG), age at mating (AM), pregnancy rate (PR) and age of the dam (AD) were determined. Besides these variables pregnant and non-pregnant heifers were also evaluated for scores of conformation (Cs), precocity (Ps) and muscularity (Ms). The systems BA and M registered significantly differences with major LW, LDG and BCS values after the dry season compared to systems B and BS. At the beginning of the mating season LW values from B, BA and M were different of BS system. At the end of the mating season no differences could be detected among the four systems regarding LDG, BCS, AM, and AD. No significant effect on the PR averages of the four feeding systems B, BA, M e BS was registered (22,2%, 24,2%, 20,7% e 13,8%). Significant differences (P<0.01) between pregnant and non-pregnant Nellore heifers could be detected for LW, BCS, AM, LDG, Cs, Ps, and Ms.

Data de desmame e desempenho reprodutivo de vacas de corte

The experiment was run at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, located in the district of Eldorado do Sul, Brazil. The objective of the study was to evaluate the effect of the date of early (01/05/99) or conventional (03/26/99) weaning on the reproductive performance of multiparous beef cows during two mating seasons, 98/99, and the subsequent, 99/00. Fifty cows had their calves weaned with an average age of 91 days old and a minimum liveweight of 70 kg (early weaning = EW), and 43 cows had calves weaned with an average age of 170 days old and mean liveweight of 131.2 kg (conventional weaning = CW). The mating periods were from 12/01/98 to 02/26/99 and from 12/06/99 to 02/28/00. Cows of EW had higher daily liveweight gains and better body condition (BC) than CW during the first breeding season (0.828 kg x 0.549 kg; 2.4 x 2.0; P<0.05). The pregnancy rate in 1999 was 40.0% x 11.1% and in 2000 it was 51.4% x 20.0% for EW and CW, respectively. There was no difference in the calving intervals. The pregnancy rate at first mating was lower than the expected, probably due to the low BC at beginning of the mating season and to the low recovery during the mating period. The EW improved cows BC during the first mating, making possible significantly better reproductive rates than the CW.

Fatores determinantes do desempenho reprodutivo de vacas Nelore na região dos Cerrados do Brasil Central

The objective of this trial was to evaluate the effects of calving order (CO) and body condition score (BCS), scale 1(thin) to 5 (fat), on reproductive performance of 468 Nellore cows (391 multiparous and 77 primiparous) grazing Brachiaria decumbens Stapf at Brazilian Central West (Cerrados region) during four breeding seasons (from 11/1 to 1/31 of the following year). Calving order quadratically affected pregnancy rate (PR) in this trial; PR of CO1 cows was 69% while that of cows from CO5 to CO8 was 90% followed by a gradual decline until 80% PR in C012 cows. Body condition score at weaning also affected PR. For instance, CO1 cows with BCS of 2.0 and 3.5 had 52.7 and 82.5% of PR, respectively. Cows from CO4 to CO8 and BCS of 3.5 showed 96% of PR. CO1 cows that calved late in the season had 37.7% of PR but independent of CO, cows that calved earlier in the calving season had PR greater than 80%. CO1 cows calved 350.12 days after the start of the mating season while multiparous cows calved earlier (328.32 days). CO1 had the longest calving interval (CI) averaging 392.10 days whereas that from CO5 to CO9 cows averaged 365 days. Calving interval was affected by year, CO, number of days spent to calve in the calving season, and body weight change in the mating season. In addition, cows body weight (BWW) and BC at weaning (BCW) were both affected by CO and year. Body weight of calves at weaning increased from CO1 to CO4/CO5 averaging 159 kg for calves from CO1 cows and 169 kg when all CO levels were included. High production and reproductive performance are obtained from CO3 to CO8 and BCS above 3.0 and 3.5 for multiparous and primiparous Nellore cows, respectively.

Sistemas de Alimentação Pós-Desmama de Bezerras de Corte para Acasalamento com 14/15 Meses de Idade

The experiment evaluated the performance of beef heifers submitted to three alternatives of autumn-winter feeding systems, during 88 days, and after this period on improved pastures all together until the end of theirs first mating season, with 14-15 months of age. The systems were: Pasture- continuous grazing on cultivated annual ryegrass (L. multiflorum Lam); supplementation- continuous grazing on natural pasture plus energy and protein supplementation; feedlot - feedlot, with sorghum silage plus non- proteic nitrogen (NNP). After this period, all heifers grazed together on improved natural pastures with annual ryegrass, white clover (Trifolium repens) and birdsfoot trefoil (Lotus corniculatus). These data were collected in a farm located in Dom Pedrito, RS, from 395 beef heifers from three genetic groups: Hereford; 3/4 Hereford -1/4 Nellore; 5/8 Hereford- 3/8 Nellore. Live weight (LW), body conditions score (BCS) and live weight daily gains (LDG) were recorded. No differences could be detected among systems for LW and LDG. Feedlot heifers had greater BCS. At the beginning and end of the mating season, heifers from pasture group were heavier and had greater BCS than heifers from feedlot and supplementation.

Desenvolvimento e desempenho reprodutivo de novilhas Nelore criadas a pasto nos cerrados do Centro-Oeste brasileiro

A model fitted to grazing females Nellore during the rearing periods of the Cerrado Region of Central Brazil was simulated and validated in this study. Body weight gain (BWG) was determined during three years as follows: 1) first dry season after weaning on Brachiaria brizantha (Hochst) Stapf., 2) rainfall season and 3) second dry season both on Panicum maximum Jacq. cv. Tanzânia and averaged 0.020, 0.550, and 0.172 kg, respectively. In the second rainfall season during the rearing period heifers grazed Brachiaria decumbens Stapf. At 24.33 months of age the heifers body weight (BW) averaged 299 kg while in the beginning of the mating season their age and BW averaged, respectively, 25.51 ± 0.99 months (CV = 3.50%) and 309.33 ± 19.19 kg (CV = 6.20%). On average, animals calved 326.71 ± 19.98 days (CV = 6.11) after the beginning of the mating season and 36.26 months of age. The mean pregnancy rate was 88.4%. The pregnant heifers were 25.58 ± 9.97 days older and 9.8 ± 7.04 kg heavier than those non-pregnant. The mean BW and body condition in the middle of the mating season were 360 ± 31.00 and 2.94 ± 0.60, before calving 436 ± 30.86 kg and 4.57 ± 0.40, and at weaning 369 ± 33.89 kg and 3.11 ± 0.64, respectively. The mean weaning rate was of 75.6%. Calves mean BW and age at weaning were of 158 ± 20.1 kg and 202 ± 16.6 days, respectively. Nellore heifers grazing Brachiaria decumbens Stapf. and bred at 24/26 months of age showed high production.

Efeitos de carga animal, pastagem melhorada e da idade de desmame no comportamento reprodutivo de vacas primíparas

Ninety two primiparous cows at three years old (46 Braford - 46 Hereford), were assigned to stocking rates (SR) of 240 kg/ha (T1) and 320 kg/ha (T2) on natural pasture, from 09.01.00 to 03.06.01, or 400 kg/ha (T3) on improved pasture of ryegrass (Lolium multiflorum L.) during 80 days postpartum, and after, at same SR of T2 on natural pasture until the conventional weaning (CW; 03.06.01). The breeding season was from 11.23.00 until 02.15.01. Early weaning (EW) was imposed to 46 cows in 01.01.01. Live weights at calving (LWC), beginning (LWB) and at the end of the breeding season (LWE) were not affected by the treatments. Treatments affected significantly the body condition at calving (BCC), beginning (BCI) and at the end of the breeding season (BCE). The Braford cows had higher LWC, LWB and LWE than the Hereford cows. The pregnancy rate (PR), calving interval (CI) and calving-conception interval (CCI) were not affected by EW. PR was not affected by the treatments (T1= 93.8%; T2= 90.6%; T3= 100%), neither by EW (EW= 97.8%; CW= 91.3%). However, at 21 days after the beginning of the breeding season, 15.6 and 17.9% of the cows in T1 and T3, respectively, were pregnant, while none cow (0.0%) in T2 was pregnant. At 42 days after the beginning of the breeding season, 46.9 and 71.4% of the cows in T1 and T3 were pregnant, respectively, and 37.5% of the cows in T2. Cows on T3 had CI (386.8 days) and CCI (101.8 days) shorter than cows on T2 (399.0 and 114.0 days, respectively). Cows on T1 had intermediary CI (390.9 days) and CCI (105.9 days), being similar to T2 and T3.

Efeito do genótipo halotano e de diferentes sistemas de produção na qualidade da carne suína

The effect of halothane genotypes (heterozygous and dominant homozygous) and intensive rearing systems (indoor, wood shavings bedding and outdoor) on pork quality were determinated. Ninety six castrated male pigs were used for the trial. Identification of the halothane genotype was determined in blood samples using the DNA-test, based on the polymerase chain reaction (PCR) amplification of the critical region of the ryanodine receptor and subsequent restricion of the amplifield fragment by the restriction fragment lengh polymorfism (RFLP) technique. The pH at 45 minutes and 24 hours after slaughter was measured on the Longissimus dorsi and Semimembranosus muscles. At the laboratory, the Longissimus dorsi muscle was used for the evaluation of the color, marbling, drip loss, defrosting loss and cooking loss and shear force. The muscle of heterozygous pigs for the halothane gene had lower pH and higher drip loss and the incidence of the PSE condition in this genotype was three times higher. The rearing system did not affect the initial and ultimate pH or water holding capacity. Indoor reared pigs had greater frequency of PSE carcass. The interaction between halothane genotypes and rearing systems had no significant effect on any trait studied.

Recria de bezerras com suplementação no outono e pastagem cultivada no inverno

This trial evaluated the effects of different levels of supplementation on the growth of weaned female beef calves grazing native pasture during the fall. Development of these same animals grazing pastures of black oat (Avena strigosa Schreb) and annual ryegrass (Lolium multiflorum Lam) during the winter were also investigated. One hundred-eighteen female calves averaging seven months of age from three distinct herds: H1 and H2 (Aberdeen Angus animals) and H3 (crossbred Aberdeen Angus animals) were used. Calves grazing the native pasture were supplemented with a commercial concentrate as follows: 0.7, 1.0 or 1.3% of body weight (BW). During the winter, animals were moved to pastures of black oat and annual ryegrass and were all maintained in the same group. The following measurements were taken: BW, body condition (BC), average daily gain (ADG), body condition gain (BCG), and relative growth (RG). No significant supplementation levels ´ herd interactions were detected. Animals grazing native pasture supplemented with 1.3% BW as concentrate had greater ADG (0.405 kg) than those supplemented with 0.7% BW (0.300 kg). The ADG of animals grazing black oat and annual ryegrass did not differ and averaged 0.820 kg. Within the three herds, animals from H3 had greater BW and BC than those from H1 and H2. Calves from H1 with lower initial BW and BC showed compensatory growth and had similar BW and BC compared to H2 calves at the end of the winter period. H1 calves had higher RG (77.1% of BW and 32.4% of BC) than H2 and H3 calves, which averaged 57.1% of BW and 14.7% of BC. Initial BW and BC were highly correlated (r=0.811) but both were not correlated with ADG during rearing. The final BW and BC were affected by initial BW and ADG during rearing. Calves with the greatest BW at weaning were not always the heaviest animals at one year of age.

Efeito da idade de desmame e suplementação no desenvolvimento de novilhas de corte

The experiment was conducted to evaluate the performance of 47 Bos taurus x Bos indicus beef heifers until two years of age. Heifers were early weaned (EW) with average age of 91 days and minimum of 70 kg of liveweight or weaned at conventional age with average of 170 days and average liveweight of 130.3 kg (CW), supplemented (Su) or not (NSu) with concentrate containing 14% crude protein and 75% total digestible nutrients (TDN) during 91 days in the first winter. The early weaning and the no supplemented group were lightier until one year of age. Weaning age did not affect pregnancy rate (77.3% and 72% to EW and CW, respectively). The supplementation during the first winter did not affect the heifers performance until two years of age. Early weaning did not affected the growth and the fertility of heifers until two years of age when compaired with the weaning at the conventional age.