SummaryExogenous amylase, sucrose, or a combination was used in diets with reduced starch content. The trial was performed in 48 lactating Holstein cows, and milk yield, milk composition, and dry matter intake were measured. Treatments did not affect production traits, but with slightly decreased feed intake and slightly greater milk production in amylase-fed cows, the calculated value of amylase in this study was $0.37/cow per day.

Chromium (Cr) feeding in early lactation increased milk production in some studies, but responses to dietary Cr during peak lactation have not been evaluated. Furthermore, interactions of essential amino acids (AA) and Cr have not been explored. Our objective was to evaluate responses to CrPr (KemTRACE chromium propionate 0.04%, Kemin Industries Inc., Des Moines, IA) and rumen-protected Lys (LysiPEARL, Kemin Industries Inc.) and Met (MetiPEARL, Kemin Industries Inc.) and their interaction in peak-lactation cows. Forty-eight individually fed Holstein cows (21 primiparous, 27 multiparous, 38 ± 15 d in milk) were stratified by calving date in 12 blocks and randomly assigned to 1 of 4 treatments within block. Treatments were control, CrPr (8 mg/d of Cr), RPLM (10 g/d of Lys and 5 g/d of Met, intestinally available), or CrPr plus RPLM. Treatments were premixed with ground corn and top-dressed at 200 g/d for 35 d. Diets consisted of corn silage, alfalfa hay, and concentrates, providing approximately 17% crude protein, 31% neutral detergent fiber, and 40% nonfiber carbohydrates. Dry matter intake (DMI) significantly increased with the inclusion of CrPr (22.2 vs. 20.8 ± 0.67 kg/d), and energy-corrected milk (ECM) yield tended to increase. In addition, CrPr increased milk protein yield and tended to increase DMI in primiparous cows but not in multiparous cows. A CrPr×week interaction was detected for milk lactose content, which was increased by CrPr during wk 1 only (4.99 vs. 4.88 ± 0.036%). As a proportion of plasma AA, lysine increased and methionine tended to increase in response to RPLM, but the inclusion of RPLM decreased N efficiency (milk protein N:N intake). Digestible energy intake, gross energy digestibility, and energy balance were not affected by treatments. We observed no treatment effects on feed efficiency or changes in body weight or body condition score. In summary, feeding CrPr increased DMI and tended to increase ECM in cows fed for 5 wk near peak lactation, with primiparous cows showing greater responses in DMI and milk protein yield than multiparous cows.

Previous research has shown that replacing up to 5% [of dietary dry matter (DM)] corn with cane molasses can partially alleviate milk fat depression when cows are fed high-concentrate, low-fiber rations containing dried distillers grains with solubles. The primary objective of this study was to determine whether dietary molasses alters milk fatty acid (FA) profile or improves solids-corrected milk yield in the context of a more typical lactation diet. A secondary objective was to assess production responses to increasing rumen-degradable protein supply when molasses was fed. Twelve primiparous and 28 multiparous Holstein cows (196 ± 39 d in milk) were blocked by parity and assigned to 4 pens. Pens were randomly allocated to treatment sequence in a 4 × 4 Latin square design, balanced for carryover effects. Treatment periods were 21 d, with 17 d for diet adaptation and 4 d for sample and data collection. Treatments were a control diet, providing 20% dried distillers grains with solubles (DM basis), 35% neutral detergent fiber, 30% starch, and 5% ether extract; a diet with 4.4% cane molasses replacing a portion of the corn grain; a diet with 2.9% molasses supplement containing 32% crude protein on a DM basis; and a diet with 5.8% (DM basis) molasses supplement. Animal-level data were analyzed using mixed models, including the fixed effect of treatment and the random effects of period, pen, period × pen interaction, and cow within pen to recognize pen as the experimental unit. Diets did not alter DM intake, milk production, milk component concentration or yield, feed efficiency (DM intake/milk yield), body weight change, or milk somatic cell count. Milk stearic acid content was increased by the diet containing 5.8% molasses supplement compared with the control diet and the diet containing 2.9% molasses supplement, but the magnitude of the effect was small (12.27, 11.75, and 11.69 ± 0.29 g/100g of FA). Production data revealed a dramatic effect of period on milk fat content and yield. Milk fat content decreased during the course of the experiment (least squares means = 3.16, 2.81, 2.93, and 2.64 ± 0.09% for periods 1 to 4, respectively), as did milk fat yield (1.20, 1.03, 0.98, and 0.79 ± 0.05 kg/d). Exchanging molasses-based products for corn at 2.9 to 5.8% of dietary DM did not influence productivity and had minute effects on milk FA profile. The limited responses in this study may have been influenced by dietary unsaturated FA content or the advancing stage of lactation of cows in the study.

bromatologic variation of the milk produced by lamancha goats fed with different forages. The objective of this experiment was to determine the effect of three forages: black sorghum (Sorghum almum), mulberry (Morus alba), and african star grass (Cynodom nlemfuensis), on the quantity and quality of goat milk. The experiment was carry out at the alfredo Volio mata experiment station of the University of costa rica located at 1542 masl, during the last trimester of 2007 on three groups of Lamancha goats. a repeated Latin square model was used. The highest milk yield was obtained when animals consumed african star grass (1.06 kg of milk/animal/day) (p<0.01) followed by mulberry (0.89 kg of milk/animal/day) and Black sorghum (0.73 kg of milk/animal/day); nevertheless, fat percentage, protein, casein, total solids and non fatty solids were improved when goats were fed with mulberry (p<0.01), and the lowest parameters were obtained with african star grass.

The objective of this study was to evaluate effects of chromium propionate (CrPr), rumen-protected lysine and methionine (RPLM), or both on metabolism, neutrophil function, and adipocyte size in lactating dairy cows (38 ± 15 d in milk). Forty-eight individually fed Holstein cows (21 primiparous, 27 multiparous) were stratified by calving date in 12 blocks and randomly assigned to 1 of 4 treatments within block. Treatments were control, CrPr (8 mg/d of Cr, KemTRACE brand chromium propionate 0.04%, Kemin Industries Inc., Des Moines, IA), RPLM (10 g/d lysine and 5 g/d methionine intestinally available, from LysiPEARL and MetiPEARL, Kemin Industries Inc.), or CrPr plus RPLM. Treatments were fed for 35 d; blood plasma samples were collected ond 21 and 35 of treatment, and blood neutrophils were isolated from 24 cows for analysis of tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β) transcript abundance in the basal state and after 12h of lipopolysaccharide (LPS) activation. Tailhead subcutaneous adipose tissue samples were collected ond 35 for measurement of adipocyte size. Plasma glucose, nonesterified fatty acids, and glucagon concentrations were unaffected by treatments, whereas plasma insulin concentration was increased by RPLM. Basal TNFα transcript abundance in neutrophils was not affected by treatment, but basal IL-1β transcript abundance was decreased by RPLM and tended to be increased by CrPr. After LPS activation, CrPr increased neutrophil TNFα transcript abundance. In addition, RPLM×parity interactions were detected for both TNFα and IL-1β abundance after LPS activation, reflecting enhanced responses in primiparous cows and attenuated responses in multiparous cows supplemented with RPLM. Adipocyte size was not affected by treatment. Supplemental CrPr and RPLM had minimal effects on metabolism when fed for 35 d near peak lactation but may modulate innate immune function in lactating dairy cows.

Consumo y calidad del forraje Trypsacum laxum de un año de edad en cabras. el experimento se ejecutó en la estación experimental alfredo Volio mata de la Universidad de costa rica ubicada a 1.542 msnm, durante el último trimestre del 2007, con el objetivo de determinar el consumo y la calidad del pasto Trypsacum laxum de un año de edad, suministrado sin ningún proceso de picado en tres tratamientos (7,5 %, 10 % y 12,5 % del peso corporal), a cabras lecheras. el mayor consumo en kg/día se presentó con el tratamiento 1 (2.200 kg/día) (p<0,01), pero la composición nutricional entre tratamientos no mostró diferencias significativas (p>0,05), manteniendo niveles de proteína cruda aceptables (8,45 a 8,87 %) para un material de tal grado de madurez.

Consumo de Pennisetum purpureum cv. king grass a tres edades de cosecha en caprinos. el objetivo de este trabajo fue determinar la edad del pasto Pennisetum purpureum cv. king grass, a la cual los caprinos presentan un mayor consumo y aprovechamiento de nutrientes. el experimento se llevó a cabo durante el segundo semestre del 2007 en la estación experimental alfredo Volio mata de la Universidad de costa rica, ubicada a 1542 msnm. se obtuvo la cantidad de pasto Pennisetum purpureum cv. king grass producida a los 60, 75 y 90 días de rebrote, consumida por caprinos (peso promedio 45 kg) de las razas saanen Lamancha y Toggenburg, distribuidas en un cuadrado latino con tres repeticiones. el mayor consumo de materia verde se obtuvo cuando el forraje fue cosechado a 60 días (p<0,01) (1810 g/animal/ día); en base seca no se mostraron diferencias significativas entre tratamientos (p>0,05). se observó una disminución gradual en el consumo de materia seca y proteína cruda conforme aumentó la edad de cosecha y la proporción de tallos en el forraje; mientras que la fibra neutro detergente y la fibra ácido detergente se comportaron de manera contraria. a menor edad del material y mayor relación hoja:tallo, las cabras aumentaron el consumo de forraje y el aprovechamiento de los nutrientes del mismo.

Digestibility and quality of Pennisetum purpureum cv. king grass at three different ages. The study was carried out at the alfredo Volio mata experimental station of the University of costa rica located at 1542 masl, from July to october 2007. The main objective was to evaluate nutritional aspects and digestibility of Pennisetum purpureum cv. king grass forage harvested at three different cutting ages (60, 75 and 90 days). a randomized complete block design was implemented; the assigned treatments were the three different forage ages evaluated in three periods with three repetitions each one. The results showed a better quality of forage harvested after 60 days of growth. The quality of king grass was affected more when materials were cut at an age of 90 days. moreover, the king grass composition was affected by the proportion of leaves and the harvest time.