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Whole cottonseed (WCS) has long been a viable supplement in southern beef production systems, but new cultivars and ginning innovations have renewed interest in its use. Ad libitum supplementation of WCS, however, leads to increased fat intake, potentially resulting in reduced fiber digestibility. However, gestating and lactating beef cows have been observed to have adequate or optimum performance under supplementation scenarios as much as 3.6 kg·animal-1·day-1. It has been hypothesized that WCS may pass through the gastrointestinal tract without being digested, thereby not interfering with whole diet digestibility. Thus, our objective was to conduct an observational screening of beef cattle offered near ad libitum levels of WCS for passage dynamics. In this case study, we sampled beef cattle (approximately 1,000 head) at a farm in central Alabama offered an average of 3.6 kg WCS·animal-1·day-1. Cattle were divided by age and stage of production across seven pastures varying in forage base. Fresh manure samples (n = 22) were collected at random from the herd. Fecal samples were sorted by wet sieving to recover undigested seed material. Counts were conducted to determine whole or fractional seed remaining. Data were analyzed using SAS v. 9.4. Across samples, recovered WCS were approximately normally distributed (W = 0.83) with a mean of 3.3 seed per sample and a range of 2 to 76. Fractional WCS recovered were normally distributed (W = 0.92) with a mean of 31.9 parts per sample and a range of 0 to4. On average, WCS recovered accounted for 0.34 g per sample, or 5.0% of the DM recovered. While caution should be used in broad interpretation of these observational results, there is sufficient evidence to suggest that high levels of WCS supplementation may seed to decreased digestive efficiency (evidenced by undigested seed in manure). These observations serve as a basis for further investigation in designed experiments to evaluate WCS digestion and passage dynamics. [ABSTRACT FROM AUTHOR]

Maintenance of pastures for grazing accounts for $132.50/animal in the United States (23% of operating costs), and pasture nutrient input represents the single greatest influence in productivity per unit area. Cultivar differences in the forage offered to cattle have the potential to manifest differences in digestive efficiency, resulting in different nutrient excretion profiles. The objective of this study was to assess the growth potential and incorporation of N, P, and K into forage material from manure from cattle fed one of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars. Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal, Russell, Tifton 44, or Tifton 85) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 23, total fecal collections were subsampled from each heifer. As a hierarchical addition, a controlled greenhouse experiment was conducted for each period [15 pots per period; 5 manure treatments (four bermudagrass diets plus a negative control) × 3 replications]. Manure was added to 4.58 L pots based on stocking rate estimates for Central Alabama (1,110 kg/ha). The pots were seeded with bermudagrass (cv. Giant) as an indicator for forage nutrient uptake. At harvest (d 70), herbage, root, and soil samples were collected. Herbage and root samples were assayed for CP. Soil samples were assayed for pH, N, P, K, Mg, and Ca. Data were analyzed using SAS v. 9.4. There was no effect of manure treatment on herbage (P = 0.88) or root DM yield (P =.00;.54 and.73 g/pot, respectively). Similarly, there was no effect of manure treatment on soil pH (P = 0.18; 5.5), P (P = 0.78; 24.2 kg/ha), or K (P = 0.42;56.7 kg/ha). Results are interpreted to mean that, regardless of the cultivar effects on ruminal digestive dynamics, there is little to no effect of the resulting manure on subsequent forage production and nutrient uptake. [ABSTRACT FROM AUTHOR]