Papers by Rebeca Rojas-Ronquillo
Journal of Agricultural Science and Technology A, 2016
The aim of this study was to evaluate the feed consumption and weight gain in calves fed with a n... more The aim of this study was to evaluate the feed consumption and weight gain in calves fed with a nutritional block made of white mulberry (Morus alba) for a 90-day-period, involving dry season months (March-May) in Tuxpan, Veracruz, Mexico. A total of 45 growing Zebu × Swiss calves with an average weight of 200 kg were assigned randomly in three groups of 15 animals, and the following treatments of nutritional block were offered to each group: grazing animals (T 0), grazing animals plus nutritious block with white mulberry (T 1), and grazing animals plus nutritious block without white mulberry (T 2). A consumption of 0.545 kg/d from block in treatment T 1 was observed, significantly improving calves growing and showing a weight gain of 0.933 kg/d. Use of white mulberry in nutritional blocks is a good alternative for growing calves, as a feeding strategy given the seasonality of pasture production in the tropics.
Revista Brasileira de Zootecnia, 2016
The objective of the study was to determine the effect of routine intramuscular injection of oxyt... more The objective of the study was to determine the effect of routine intramuscular injection of oxytocin to induce milk ejection on behavior assessed in terms of stress and rectal temperature in crossbred cows (Bos indicus × Bos taurus) in the tropics of Veracruz, México. Immediately after calving, cows were milked twice a day (n = 210) and randomly assigned to receive at each milking: 10 IU (0.5 mL) of oxytocin intramuscularly (n = 70); 0.5 mL of saline solution intramuscularly (n = 70); or no injection (n = 70). The following behavioral indicators of stress were observed: trampling, kicking, tail movement, failure to eat, jumping to avoid injection, vocalization, urination, and defecation. After milking, rectal temperature (RT) was measured. Statistical analysis was performed using ANOVA and chi-square. There were no differences in terms of behavioral stress indicators or rectal temperature in cows injected with oxytocin or saline solution, but both groups had greater behavioral indicators of stress and RT compared with non-injected cows. Cows injected with oxytocin or saline solution manifested a higher percentage of animals that trampled (96.8%), kicked (32%), ceased eating (61.2%), moved the tail (81.2%), jumped (20.9%) and avoided the injection (78.2%), compared with non-injected cows. Cows injected with oxytocin and saline solution had higher rectal temperature (39.13±0.08 ºC) compared with non-injected cows (38.96±0.12 ºC). All injected cows had higher behavioral indicators of stress measurements and rectal temperature regardless of the solution, suggesting that cows injected routinely and intramuscularly do not become habituated to this, even though some cows were injected more than 600 times throughout lactation.
International Dairy Journal, 2012
Journal of Agricultural Science and Technology A, 2015
The objective of the study was to determine the effects of different doses of recombinant bovine ... more The objective of the study was to determine the effects of different doses of recombinant bovine somatotropin (rBST) in milk production and body weight changes in crossbred Bos indicus x Bos taurus cows under tropical conditions of northern Veracruz. Nine multiparous cows at 57 ± 7 days postpartum were assigned randomly to receive rBST every 14 days, and 4 applications of the following treatments: 1) 500 mg zinc as an excipient (L500), 2) 325 mg zinc as an excipient (L325), and 3) 500 mg Vitamin E as excipient (B500). The milk production was measured daily for 70 days, starting 14 days before treatments to use as their own controls. Waikatos® weighers were used to measure the milk. Cows were maintained in a system of intensive rotational grazing of Brachiaria brizantha and Cynodon plectostachyus. Cows were milked twice a day and at milking cows were given commercial feed (18 % crude protein) at 1 kg of feed per 3 liters of milk produced. Statistical analysis was performed using ANOV...
The aim of this study was to evaluate the effect of oatmeal on weight gain and carcass yield, und... more The aim of this study was to evaluate the effect of oatmeal on weight gain and carcass yield, under a housing system. 30 Swiss × Zebu steers were used, with an approximate weight of 353 kg, which were assigned under a completely randomized design in three treatments. T1 (control) without concentrate oatmeal; T2 concentrate + 30% poultry meal and T3 concentrate + 35% poultry meal. The composition of the concentrate was based on ground sorghum, maize grain, wheat bran, ground mineral salt bale with 18% crude protein and 70% TDN. A significant effect (p 0.05) on the percentage of carcass weight of 53.0 was observed; 59.5 and 58.8% for T1, T2 and T3, respectively. The results indicate that supplementation based oatmeal 35% promoted greater yield in feedlot steers.
The aim of the study was to determine the effect of breeding program and breed in the percentage ... more The aim of the study was to determine the effect of breeding program and breed in the percentage of pregnancies of housed hair sheep in tropical conditions of northern Veracruz. The study was conducted on a commercial farm using hair sheep housed by breed (29 ewes and one ram per pen) and all ewes had lambed recently. The following breeds were used: Black Belly (BB, n=110), Dorper (D, n=270) and Katahdin (K, n=131). The ewes were randomly assigned into 2 breeding programs: 1) Continuous breeding (CB), where the rams were introduced with the ewes of their breed immediately after lambing and remained with the ewes all the time (BB, n=55; D, n=107 and K, n=103), and 2) Breeding 45 days after lambing (B45) where the rams were introduced with the ewes of their breed 45 days after lambing (BB, n=55; D, n=163; K, n=28) and rams remained with the ewes for 60 days. Pregnancy diagnosis was performed simultaneously in the CB and B45 by ultrasound 30 days after retired rams from the B45. Statis...
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Papers by Rebeca Rojas-Ronquillo